Dosing & Uses
Dosage Forms & Strengths
tablet
- 200mg (as sulfate)
- 300mg (as sulfate)
tablet, extended-release
- 300mg (as sulfate)
- 324mg (as gluconate)
injectable solution
- 80mg/mL (as gluconate) - discontinued from U.S. market
Arrhythmias
Quinidine Sulfate
- Test Dose: 200 mg PO quinidine sulfate several hr before full dosage
- Atrial fibrillation: 300-400 mg PO q6hr
- PSVT: 400-600 mg PO q2-3hr until paroxysm terminated
- Atrial/Ventricular Premature Contractions: 200-300 mg PO q6-8hr
- Maint: 200-400 mg PO q6-8hr or 600 mg of SR PO q8-12hr
- No more than 3-4 g/day
Quinidine Gluconate
- 324-660 mg PO q8-12hr
- Maintenance: 648 mg PO q12hr OR 324-660 mg PO q8hr
- PSVT: 400 - 600 mg PO q2-3hr until paroxysm is terminated
- IV: Usual <5 mg/kg (but may need up to 10 mg/kg) at 0.25 mg/kg/min
Malaria
Quinidine gluconate for injection is no longer available in the U.S.
Quinidine Gluconate
- Regimen I
- Load: 24 mg/kg diluted in 250 mL NS IV infusion over 4 hours
- Maintenance: Follow by 12 mg/kg IV infusion over 4 hours q8hr beginning 8 hr after initiation of loading dose except in patients able to swallow the same doses of quinidine are administered using 300 mg quinidine sulfate tablets
- Regimen II
- Load: 10 mg/kg diluted in 5 mL/kg NS IV over 1-2 hr
- Maintenance: Follow by 0.02 mg/kg/min continuous IV infusion; in patients able to swallow oral quinine is administered every 8 hr to give as much quinine as patient received in quinidine q8hr
- PO regimen: 300 mg quinidine or 650 mg quinine PO q8hr for 3 days (Africa and South America) or 7 days (Southeast Asia) or until parasitemia is reduced to 1%
Dosage Modifications
Hepatic impairment: Not studied
Renal impairment
- CrCl <10 mL/min: Administer 75% of normal dose
- CrCl ≥10 L/min: Dose adjustment not necessary
Pseudobulbar Affect (Off-Label)
Excessive laughing or crying, or involuntary emotional expression affects 20-50% of patients with ALS
30 mg PO bid (administer with dextromethorphan)
Dosage Forms & Strengths
tablet
- 200mg (as sulfate)
- 300mg (as sulfate)
tablet, controlled-release
- 300mg (as sulfate)
- 324mg (as gluconate)
injectable solution
- 80mg/mL
Arrhythmias
Quinidine sulfate: 30 mg/kg/day or 900 mg/m²/day PO given in 5 divided doses OR 15-60 mg/kg/day divided q6hr PO
Test dose: 2 mg/kg PO quinidine sulfate; test dose not to exceed 200 mg
Malaria
Quinidine gluconate for injection is no longer available in the U.S.
Load: 10 mg/kg diluted in 5 mL/kg NS IV over 1-2 hr
Maintenance: Follow by 0.02 mg/kg/min continuous IV infusion; in patients able to swallow oral quinine is administered every 8 hr to give as much quinine as patient received in quinidine q8hr
PO regimen: 650 mg quinine PO q8hr for 3 days (Africa and South America) or 7 days (Southeast Asia) or until parasitemia is reduced to 1%
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (74)
- amitriptyline
quinidine and amitriptyline both increase QTc interval. Contraindicated.
- amoxapine
quinidine and amoxapine both increase QTc interval. Contraindicated.
- artemether/lumefantrine
quinidine and artemether/lumefantrine both increase QTc interval. Contraindicated.
- chloroquine
quinidine will increase the level or effect of chloroquine by Other (see comment). Contraindicated. Quinidine is contraindicated in patients receiving drugs that both prolong the QT interval and are metabolized by CYP2D6, such as chloroquine
- chlorpromazine
chlorpromazine and quinidine both increase QTc interval. Contraindicated.
- clarithromycin
quinidine and clarithromycin both increase QTc interval. Contraindicated.
- clomipramine
quinidine and clomipramine both increase QTc interval. Contraindicated.
- cobimetinib
quinidine will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with strong CYP3A4 inhibitors with (increases cobimetinib systemic exposure by 6.7-fold).
- conivaptan
quinidine will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of conivaptan with strong CYP3A4 inhibitors is contraindicated.
- desipramine
quinidine and desipramine both increase QTc interval. Contraindicated.
- dihydroergotamine
quinidine increases levels of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- dihydroergotamine intranasal
quinidine increases levels of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- disopyramide
quinidine and disopyramide both increase QTc interval. Contraindicated.
- dofetilide
quinidine and dofetilide both increase QTc interval. Contraindicated.
quinidine, dofetilide. Either increases effects of the other by pharmacodynamic synergism. Contraindicated. Additive cardiac effects. - dosulepin
quinidine and dosulepin both increase QTc interval. Contraindicated.
- doxepin
quinidine and doxepin both increase QTc interval. Contraindicated.
- dronedarone
quinidine and dronedarone both increase QTc interval. Contraindicated.
- droperidol
quinidine and droperidol both increase QTc interval. Contraindicated.
- eliglustat
quinidine will increase the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors are contraindicated with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors
quinidine increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.
eliglustat and quinidine both increase QTc interval. Contraindicated. - epinephrine
epinephrine and quinidine both increase QTc interval. Contraindicated.
- epinephrine racemic
epinephrine racemic and quinidine both increase QTc interval. Contraindicated.
- erythromycin base
quinidine and erythromycin base both increase QTc interval. Contraindicated.
- erythromycin ethylsuccinate
quinidine and erythromycin ethylsuccinate both increase QTc interval. Contraindicated.
- erythromycin lactobionate
quinidine and erythromycin lactobionate both increase QTc interval. Contraindicated.
- erythromycin stearate
quinidine and erythromycin stearate both increase QTc interval. Contraindicated.
- fingolimod
fingolimod increases effects of quinidine by pharmacodynamic synergism. Contraindicated. Due to increased risk of bradycardia, AV block, and torsade de pointes, concomitant use is contraindicated.
fingolimod and quinidine both increase QTc interval. Contraindicated. - flibanserin
quinidine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.
- fluconazole
fluconazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
quinidine and fluconazole both increase QTc interval. Contraindicated. - fluphenazine
fluphenazine and quinidine both increase QTc interval. Contraindicated.
- gemifloxacin
gemifloxacin and quinidine both increase QTc interval. Contraindicated.
- goserelin
goserelin increases toxicity of quinidine by QTc interval. Contraindicated. Increases risk of torsades de pointes.
- haloperidol
quinidine and haloperidol both increase QTc interval. Contraindicated.
- ibutilide
quinidine and ibutilide both increase QTc interval. Contraindicated.
- imipramine
quinidine and imipramine both increase QTc interval. Contraindicated.
- indapamide
quinidine and indapamide both increase QTc interval. Contraindicated.
- itraconazole
itraconazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Both drugs will increase QT interval. Coadministration of quinidine and itraconazole is contraindicated during and 2 weeks after itraconazole treatment.
quinidine will increase the level or effect of itraconazole by P-glycoprotein (MDR1) efflux transporter. Contraindicated. Both drugs will increase QT interval
quinidine and itraconazole both increase QTc interval. Contraindicated. - ivabradine
quinidine will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of ivabradine with strong CYP3A4 inhibitors is contraindicated.
- ketoconazole
ketoconazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
quinidine and ketoconazole both increase QTc interval. Contraindicated. - lefamulin
lefamulin will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.
- leuprolide
leuprolide increases toxicity of quinidine by QTc interval. Contraindicated. Increases risk of torsades de pointes.
- levoketoconazole
levoketoconazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
quinidine and levoketoconazole both increase QTc interval. Contraindicated. - lofepramine
quinidine and lofepramine both increase QTc interval. Contraindicated.
- lomitapide
quinidine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.
- lovastatin
quinidine will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase systemic statin exposure and risk of myopathy, including rhabdomyolysis
- lumefantrine
quinidine and lumefantrine both increase QTc interval. Contraindicated.
- maprotiline
quinidine and maprotiline both increase QTc interval. Contraindicated.
- mifepristone
mifepristone increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated with CYP3A substrates that have a narrow therapeutic index; combination may prolong QT interval .
- moxifloxacin
quinidine and moxifloxacin both increase QTc interval. Contraindicated.
- naloxegol
quinidine will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of naloxegol with strong CYP3A4 inhibitors can significantly increase naloxegol systemic exposure which may precipitate opioid withdrawal symptoms
- nilotinib
quinidine and nilotinib both increase QTc interval. Contraindicated.
- nirmatrelvir
nirmatrelvir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Nirmatrelvir/ritonavir is contraindicated with drugs that are highly dependent on CYP3A for clearance and for which elevated concentrations are associated with serious and/or life-threatening reactions.
- nirmatrelvir/ritonavir
nirmatrelvir/ritonavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Nirmatrelvir/ritonavir is contraindicated with drugs that are highly dependent on CYP3A for clearance and for which elevated concentrations are associated with serious and/or life-threatening reactions.
- nortriptyline
quinidine and nortriptyline both increase QTc interval. Contraindicated.
- octreotide
quinidine and octreotide both increase QTc interval. Contraindicated.
- octreotide (Antidote)
quinidine and octreotide (Antidote) both increase QTc interval. Contraindicated.
- pentamidine
quinidine and pentamidine both increase QTc interval. Contraindicated.
- perphenazine
perphenazine and quinidine both increase QTc interval. Contraindicated.
- pimozide
quinidine and pimozide both increase QTc interval. Contraindicated.
- procainamide
quinidine and procainamide both increase QTc interval. Contraindicated.
- prochlorperazine
prochlorperazine and quinidine both increase QTc interval. Contraindicated.
- promazine
promazine and quinidine both increase QTc interval. Contraindicated.
- promethazine
promethazine and quinidine both increase QTc interval. Contraindicated.
- protriptyline
quinidine and protriptyline both increase QTc interval. Contraindicated.
- regorafenib
quinidine, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase regorafenib levels and decrease exposure of the active metabolites M-2 and M-5.
- saquinavir
saquinavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- sotalol
quinidine and sotalol both increase QTc interval. Contraindicated.
- tetrabenazine
tetrabenazine and quinidine both increase QTc interval. Contraindicated.
- thioridazine
thioridazine and quinidine both increase QTc interval. Contraindicated.
- tipranavir
tipranavir increases levels of quinidine by decreasing metabolism. Contraindicated.
tipranavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. - trazodone
quinidine and trazodone both increase QTc interval. Contraindicated.
- trifluoperazine
trifluoperazine and quinidine both increase QTc interval. Contraindicated.
- trimipramine
quinidine and trimipramine both increase QTc interval. Contraindicated.
- voriconazole
voriconazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Elevated and toxic levels of quinidine may occur potentiating the risk for QT prolongation and cardiac arrhythmias.
quinidine and voriconazole both increase QTc interval. Contraindicated. - ziprasidone
quinidine and ziprasidone both increase QTc interval. Contraindicated.
Serious - Use Alternative (230)
- adagrasib
adagrasib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of adagrasib, a CYP3A4 inhibitor, with sensitive CYP3A substrates unless otherwise recommended in the prescribing information for these substrates.
adagrasib, quinidine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients. - ado-trastuzumab emtansine
quinidine increases levels of ado-trastuzumab emtansine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. DM1, the cytotoxic component, is metabolized mainly by CYP3A4; strong CYP3A4 inhibitors may increase DM1 exposure and toxicity.
- afatinib
quinidine increases levels of afatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Reduce afatinib daily dose by 10 mg if not tolerated when coadministered with P-gp inhibitors.
- alfuzosin
alfuzosin and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- amikacin
quinidine will increase the level or effect of amikacin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- amiodarone
quinidine will increase the level or effect of amiodarone by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug.
quinidine and amiodarone both increase QTc interval. Avoid or Use Alternate Drug. - amisulpride
quinidine and amisulpride both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.
- amitriptyline
quinidine will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- anagrelide
anagrelide and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- apalutamide
apalutamide will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
- apixaban
quinidine will increase the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If taking apixaban dose >2.5 mg BID, decrease dose by 50% if coadministered with strong dual inhibitors of CYP3A4 and P-gp; if currently taking apixaban 2.5 mg PO BID, avoid coadministration with strong dual inhibitors of CYP3A4 and P-gp
- apomorphine
apomorphine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- aripiprazole
aripiprazole and quinidine both increase QTc interval. Contraindicated.
- arsenic trioxide
quinidine and arsenic trioxide both increase QTc interval. Avoid or Use Alternate Drug.
- asenapine
asenapine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- asenapine transdermal
asenapine transdermal and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- atomoxetine
atomoxetine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- atorvastatin
quinidine will increase the level or effect of atorvastatin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- axitinib
quinidine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, reduce axitinib dose by 50%.
- bazedoxifene/conjugated estrogens
quinidine will increase the level or effect of bazedoxifene/conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- bedaquiline
quinidine will increase the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inhibitors for >14 consecutive days, unless the benefit of treatment outweighs the risk
- bosutinib
quinidine increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors increases bosutinib plasma concentration ~5-fold.
quinidine increases levels of bosutinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. - bremelanotide
bremelanotide will decrease the level or effect of quinidine by Other (see comment). Avoid or Use Alternate Drug. Bremelanotide may slow gastric emptying and potentially reduces the rate and extent of absorption of concomitantly administered oral medications. Avoid use when taking any oral drug that is dependent on threshold concentrations for efficacy. Interactions listed are representative examples and do not include all possible clinical examples.
- brigatinib
brigatinib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Brigatinib induces CYP3A4 in vitro. Coadministration with CYP3A4 substrates, particularly those with a narrow therapeutic index, can result in decreased concentrations and loss of efficacy. If unable to avoid coadministration, monitor CYP3A4 substrate levels and adjust dose as needed.
- budesonide
quinidine will increase the level or effect of budesonide by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- buprenorphine
buprenorphine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine buccal
buprenorphine buccal and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine subdermal implant
buprenorphine subdermal implant and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine transdermal
buprenorphine transdermal and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine, long-acting injection
buprenorphine, long-acting injection and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- cabozantinib
quinidine will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor is required, decrease cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inhibitor discontinued.
- carbamazepine
carbamazepine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- carvedilol
quinidine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- ceritinib
quinidine increases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid if possible; if concomitant use is unavoidable, reduce ceritinib dose by ~33%; after discontinuation of strong CYP3A inhibitor, resume at previous dose.
ceritinib increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concurrent use of CYP3A substrates known to have narrow therapeutic indices or substrates primarily metabolized by CYP3A during treatment with ceritinib; if use of these medications is unavoidable, consider dose.
ceritinib and quinidine both increase QTc interval. Avoid or Use Alternate Drug. - chloroquine
chloroquine increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug.
- chlorpromazine
quinidine, chlorpromazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- cimetidine
cimetidine will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
quinidine will increase the level or effect of cimetidine by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug. - clarithromycin
clarithromycin will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- clomipramine
quinidine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- clozapine
clozapine and quinidine both increase QTc interval. Contraindicated.
- colchicine
quinidine will increase the level or effect of colchicine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid use of colchicine with P-gp inhibitors. If coadministration is necessary, decrease colchicine dose or frequency as recommended in prescribing information. Use of any colchicine product in conjunction with P-gp inhibitors is contraindicated in patients with renal or hepatic impairment.
- conjugated estrogens
quinidine will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- conjugated estrogens, vaginal
quinidine will increase the level or effect of conjugated estrogens, vaginal by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- cortisone
quinidine will increase the level or effect of cortisone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- crizotinib
crizotinib increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of crizotinib with CYP3A substrates with narrow therapeutic indices should be avoided. ECG monitoring is recommended, along with drugs that may prolong the QT interval.
crizotinib and quinidine both increase QTc interval. Avoid or Use Alternate Drug. - dabrafenib
quinidine increases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- dapsone topical
quinidine, dapsone topical. unspecified interaction mechanism. Avoid or Use Alternate Drug. Avoid coadministration of dapsone topical with oral dapsone or antimalarial medications because of the potential for hemolytic reactions.
- dasatinib
quinidine and dasatinib both increase QTc interval. Avoid or Use Alternate Drug.
- deflazacort
quinidine will increase the level or effect of deflazacort by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- desipramine
quinidine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- dexamethasone
quinidine will increase the level or effect of dexamethasone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- digoxin
quinidine will increase the level or effect of digoxin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
quinidine will increase the level or effect of digoxin by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug. - diphenhydramine
quinidine, diphenhydramine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of prolonged QTc interval.
- docetaxel
quinidine will increase the level or effect of docetaxel by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- dofetilide
quinidine will increase the level or effect of dofetilide by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug.
dofetilide increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug. - dolasetron
quinidine and dolasetron both increase QTc interval. Avoid or Use Alternate Drug.
- donepezil
donepezil and quinidine both increase QTc interval. Contraindicated.
- doxepin
quinidine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Both agents increase QTc interval.
- duloxetine
quinidine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- edoxaban
quinidine will increase the level or effect of edoxaban by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Dose adjustment may be required with strong P-gp inhibitors. DVT/PE treatment: Decrease dose to 30 mg PO once daily. NVAF: No dose reduction recommended
- efavirenz
efavirenz and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- encorafenib
encorafenib and quinidine both increase QTc interval. Avoid or Use Alternate Drug. Encorafenib is associated with dose-dependent QTc interval prolongation. Avoid with drugs known to prolong QT interval.
- entrectinib
quinidine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.
- erdafitinib
erdafitinib, quinidine. Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid coadministration during initial dosing adjustment period (ie, first 21 days). Increases in serum phosphate levels are a pharmacodynamic effect of FGFR inhibition. Serum phosphate binders may obscure decisions regarding initial dosage increase.
erdafitinib, quinidine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with erdafitinib and sensitive CYP3A4 substrates with narrow therapeutic indices. Erdafitinib may altered plasma concentrations of CYP3A4 substrates, leading to either loss of activity or increased toxicity of the substrate.
erdafitinib will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index. - eribulin
eribulin and quinidine both increase QTc interval. Avoid or Use Alternate Drug. Potential for enhanced QTc-prolonging effects; if concurrent use is necessary then ECG monitoring is recommended.
- erlotinib
quinidine will increase the level or effect of erlotinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- erythromycin base
erythromycin base will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin ethylsuccinate
erythromycin ethylsuccinate will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin lactobionate
erythromycin lactobionate will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin stearate
erythromycin stearate will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- escitalopram
escitalopram increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug.
- estradiol
quinidine will increase the level or effect of estradiol by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- estrogens conjugated synthetic
quinidine will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- estropipate
quinidine will increase the level or effect of estropipate by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- ethinylestradiol
quinidine will increase the level or effect of ethinylestradiol by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- everolimus
quinidine will increase the level or effect of everolimus by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- fentanyl
quinidine will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
- fentanyl intranasal
quinidine will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
- fentanyl transdermal
quinidine will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
- fentanyl transmucosal
quinidine will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
- fexinidazole
fexinidazole and quinidine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels and/or prolong QT interval.
fexinidazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates. - flecainide
quinidine will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
quinidine and flecainide both increase QTc interval. Avoid or Use Alternate Drug. - fludrocortisone
quinidine will increase the level or effect of fludrocortisone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- fluoxetine
quinidine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
quinidine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. - fluphenazine
quinidine, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- fluticasone intranasal
quinidine will increase the level or effect of fluticasone intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase systemic corticosteroid adverse effects; monitor for signs/symptoms of high corticosteroid concentrations including Cushing type signs/symptoms.
- fluvoxamine
fluvoxamine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- formoterol
quinidine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.
- fosamprenavir
fosamprenavir increases levels of quinidine by unspecified interaction mechanism. Avoid or Use Alternate Drug.
- foscarnet
quinidine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- gadobenate
gadobenate and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- gentamicin
quinidine will increase the level or effect of gentamicin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- gilteritinib
gilteritinib and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- glasdegib
quinidine and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.
- granisetron
granisetron and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- haloperidol
quinidine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- histrelin
histrelin increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.
- hydrocortisone
quinidine will increase the level or effect of hydrocortisone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- hydromorphone
quinidine will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- hydroxychloroquine sulfate
hydroxychloroquine sulfate and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- hydroxyzine
hydroxyzine increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.
- ibrutinib
quinidine increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.
- idelalisib
quinidine will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur
idelalisib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates - iloperidone
quinidine will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
quinidine and iloperidone both increase QTc interval. Avoid or Use Alternate Drug. - imatinib
quinidine will increase the level or effect of imatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- imipramine
quinidine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- indinavir
quinidine will increase the level or effect of indinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- inotuzumab
inotuzumab and quinidine both increase QTc interval. Avoid or Use Alternate Drug. If unable to avoid concomitant use, obtain ECGs and electrolytes before and after initiation of any drug known to prolong QTc, and periodically monitor as clinically indicated during treatment.
- ivermectin
quinidine will increase the level or effect of ivermectin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- ivosidenib
ivosidenib and quinidine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.
ivosidenib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs. - lapatinib
quinidine will increase the level or effect of lapatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
quinidine and lapatinib both increase QTc interval. Avoid or Use Alternate Drug. - lasmiditan
lasmiditan increases levels of quinidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- levofloxacin
quinidine and levofloxacin both increase QTc interval. Avoid or Use Alternate Drug.
- lithium
lithium and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- lofepramine
quinidine will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- lonafarnib
lonafarnib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.
quinidine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown. - loperamide
quinidine will increase the level or effect of loperamide by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- lopinavir
lopinavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- lorlatinib
lorlatinib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid use of lorlatinib with CYP3A substrates, where minimal concentration changes may lead to serious therapeutic failures of the substrate. If concomitant use is unavoidable, increase CYP3A substrate dosage in accordance with approved product labeling.
- lovastatin
quinidine will increase the level or effect of lovastatin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- lumacaftor/ivacaftor
lumacaftor/ivacaftor will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Lumacaftor is a strong inducer of CYP3A. Avoid coadministration with sensitive CYP3A substrates or CYP3A substrates with a narrow therapeutic index.
- lurasidone
lurasidone increases toxicity of quinidine by Other (see comment). Avoid or Use Alternate Drug. Comment: Interaction applies only in setting of acute lurasidone overdose. Lurasidone may enhance QTc prolonging effects of quinidine in overdose setting.
- macimorelin
macimorelin and quinidine both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.
- macitentan
quinidine will increase the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inhibitors
- maraviroc
quinidine will increase the level or effect of maraviroc by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- mefloquine
quinidine, mefloquine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of ECG abnormalities, cardiac arrest.
mefloquine increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents. - mestranol
quinidine will increase the level or effect of mestranol by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- methadone
quinidine and methadone both increase QTc interval. Avoid or Use Alternate Drug.
- methamphetamine
quinidine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- methylprednisolone
quinidine will increase the level or effect of methylprednisolone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- metoclopramide intranasal
quinidine will increase the level or effect of metoclopramide intranasal by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Concurrent use of metoclopramide intranasal and strong CYP2D6 inhibitors is not recommended since the metoclopramide intranasal dose cannot be adjusted.
- metoprolol
quinidine will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. If concurrent therapy required, monitor cardiac function carefully (blood pressure, heart rate). A dosage adjustment may be required for both drugs.
- mexiletine
quinidine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- mirtazapine
mirtazapine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- mobocertinib
mobocertinib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use is unavoidable, increase CYP3A4 substrate dosage in accordance with its prescribing information.
mobocertinib and quinidine both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently. - morphine
quinidine will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- nebivolol
quinidine will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Monitor blood pressure. Reduced doses of nebivolol may be necessary.
- nefazodone
nefazodone will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nelfinavir
quinidine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
nelfinavir increases levels of quinidine by decreasing metabolism. Contraindicated. - neomycin PO
quinidine will increase the level or effect of neomycin PO by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- nilotinib
nilotinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Additive QT prolongation may occur during coadministration of nilotinib and quinidine. Coadministration of nilotinib and a drug that prolongs the QT interval such as dronedarone is not advised
quinidine will increase the level or effect of nilotinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. - nortriptyline
quinidine will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- ofloxacin
quinidine and ofloxacin both increase QTc interval. Avoid or Use Alternate Drug.
- olanzapine
olanzapine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- olaparib
quinidine will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A inhibitors cannot be avoided, reduce olaparib dose to 150 mg (capsule) or 100 mg (tablet) PO BID. Do not substitute tablets with capsules.
- olutasidenib
olutasidenib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of olutasidenib (a CYP3A4 inducer) with sensitive CYP3A substrates unless otherwise instructed in substrates prescribing information. If unavoidable, monitor for loss of therapeutic effect of sensitive CYP3A4 substrates.
- ondansetron
quinidine and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.
- oxaliplatin
oxaliplatin and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- oxycodone
quinidine will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
quinidine increases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Oxycodone dose reduction may be warranted when coadministered with strong CYP3A4 inhibitors. - oxymorphone
quinidine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- paclitaxel
quinidine will increase the level or effect of paclitaxel by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- paclitaxel protein bound
quinidine will increase the level or effect of paclitaxel protein bound by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- pacritinib
pacritinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- palbociclib
quinidine will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of palbociclib with strong CYP3A inhibitors. If unable to avoid, reduce palbociclib dose to 75 mg/day.
- paliperidone
quinidine will increase the level or effect of paliperidone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
quinidine and paliperidone both increase QTc interval. Avoid or Use Alternate Drug. - panobinostat
quinidine and panobinostat both increase QTc interval. Avoid or Use Alternate Drug. Panobinostat is known to significantly prolong QT interval. Panobinostat prescribing information states use with drugs known to prolong QTc is not recommended.
- paromomycin
quinidine will increase the level or effect of paromomycin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- paroxetine
quinidine and paroxetine both increase QTc interval. Avoid or Use Alternate Drug.
- perphenazine
quinidine, perphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- pexidartinib
quinidine and pexidartinib both increase inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.
pexidartinib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of pexidartinib (a CYP3A4 inducer) with sensitive CYP3A substrates may lead to serious therapeutic failures. If concomitant use is unavoidable, increase the CYP3A substrate dosage in accordance with approved product labeling. - pimavanserin
pimavanserin and quinidine both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.
- pitolisant
quinidine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.
- pomalidomide
quinidine increases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
quinidine increases levels of pomalidomide by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. - ponatinib
quinidine increases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease ponatinib starting dose to 30 mg qDay if coadministration with strong CYP3A4 inhibitors cannot be avoided.
- ponesimod
ponesimod, quinidine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Consult cardiologist if considering treatment. Generally, should not be initiated in patients who are concurrently taking QT prolonging drugs with known arrhythmogenic properties, such as HR-lowering calcium channel blockers (eg, verapamil, diltiazem).
- posaconazole
posaconazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of posaconazole in combination with drugs that both prolong the QT interval and are substrates for CYP3A4 is contraindicated
quinidine will increase the level or effect of posaconazole by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
quinidine and posaconazole both increase QTc interval. Avoid or Use Alternate Drug. - prednisolone
quinidine will increase the level or effect of prednisolone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- prednisone
quinidine will increase the level or effect of prednisone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- pretomanid
quinidine, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
- primaquine
primaquine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- procainamide
quinidine will increase the level or effect of procainamide by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug.
- prochlorperazine
quinidine, prochlorperazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- promazine
quinidine, promazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- promethazine
quinidine, promethazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- propafenone
quinidine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- propranolol
quinidine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Monitor patients for hypotension, bradycardia, arrhythmias and heart failure.
- ranolazine
quinidine and ranolazine both increase QTc interval. Avoid or Use Alternate Drug.
- red yeast rice
quinidine will increase the level or effect of red yeast rice by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. May increase creatine kinase levels and increase risk of myopathy or rhabdomyolysis; red yeast rice contains monocolin K (reportedly identical to lovastatin)
- repotrectinib
quinidine will increase the level or effect of repotrectinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
repotrectinib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Repotrectinib is a CYP3A4 inducer. Avoid coadministration with CYP3A substrates where minimal concentration changes can cause reduced efficacy, unless otherwise recommended their prescribing information. - ribociclib
ribociclib and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- rifabutin
rifabutin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- rifampin
rifampin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- rimegepant
quinidine will increase the level or effect of rimegepant by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- riociguat
quinidine will increase the level or effect of riociguat by decreasing metabolism. Avoid or Use Alternate Drug. Coadministration of riociguat (substrate of CYP isoenzymes 1A1, 2C8, 3A, 2J2) with strong CYP inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed
quinidine will increase the level or effect of riociguat by Other (see comment). Avoid or Use Alternate Drug. Coadministration of riociguat (an ABCG2 [BCRP] substrate) with strong ABCG2 inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed - risperidone
quinidine will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
quinidine and risperidone both increase QTc interval. Avoid or Use Alternate Drug. - ritonavir
quinidine will increase the level or effect of ritonavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
ritonavir increases levels of quinidine by decreasing metabolism. Contraindicated. - romidepsin
quinidine will increase the level or effect of romidepsin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
quinidine and romidepsin both increase QTc interval. Avoid or Use Alternate Drug. - ruxolitinib
quinidine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L
- ruxolitinib topical
quinidine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L
- saquinavir
quinidine will increase the level or effect of saquinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- silodosin
quinidine will increase the level or effect of silodosin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- siponimod
siponimod, quinidine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Because of the potential additive effects on heart rate, siponimod should generally not be initiated in patients taking QT prolonging drugs with known arrhythmogenic properties, heart rate lowering calcium channel blockers, or other drugs that may decrease heart rate. If treatment considered, obtain cardiology consult regarding switching to non-heart-rate lowering drugs or appropriate monitoring for treatment initiation.
- sirolimus
quinidine will increase the level or effect of sirolimus by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- sonidegib
quinidine will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong CYP3A4 inhibitors.
- sotorasib
sotorasib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the CYP3A4 substrate for dosage modifications
sotorasib will decrease the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications. - squill
quinidine increases toxicity of squill by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- St John's Wort
St John's Wort will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- streptomycin
quinidine will increase the level or effect of streptomycin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- sulfamethoxazole
quinidine and sulfamethoxazole both increase QTc interval. Avoid or Use Alternate Drug.
- sunitinib
sunitinib and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- suvorexant
quinidine increases levels of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Suvorexant not recommended with use of strong CYP3A4 inhibitors.
- tacrolimus
quinidine will increase the level or effect of tacrolimus by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
tacrolimus and quinidine both increase QTc interval. Avoid or Use Alternate Drug. - tamsulosin
quinidine increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- telavancin
quinidine and telavancin both increase QTc interval. Avoid or Use Alternate Drug.
- tepotinib
tepotinib will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.
- thioridazine
quinidine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
quinidine, thioridazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects. - timolol
quinidine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- tobramycin
quinidine will increase the level or effect of tobramycin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- tofacitinib
quinidine increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce tofacitinib dose to 5 mg qDay when coadministered with potent CYP3A4 inhibitors.
- tolvaptan
quinidine will increase the level or effect of tolvaptan by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- topotecan
quinidine will increase the level or effect of topotecan by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Product labeling for PO topotecan recommends avoiding concomitant use of P-gp inhibitors; the interaction with IV topotecan may be less severe but is still likely of clinical significance
- toremifene
quinidine and toremifene both increase QTc interval. Avoid or Use Alternate Drug. Concurrent use of toremifene with agents causing QT prolongation should be avoided. If concomitant use is required it's recommended that toremifene be interrupted. If interruption not possible, patients requiring therapy with a drug that prolongs QT should be closely monitored. ECGs should be obtained for high risk patients.
- trifluoperazine
quinidine, trifluoperazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.
- trimethoprim
quinidine and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.
- triptorelin
triptorelin increases toxicity of quinidine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.
- tropisetron
quinidine and tropisetron both increase QTc interval. Avoid or Use Alternate Drug.
- tucatinib
tucatinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.
- umeclidinium bromide/vilanterol inhaled
quinidine increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.
- vandetanib
quinidine, vandetanib. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. Avoid coadministration with drugs known to prolong QT interval; if a drug known to prolong QT interval must be used, more frequent ECG monitoring is recommended.
- venetoclax
quinidine will increase the level or effect of venetoclax by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If a P-gp inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.
- venlafaxine
quinidine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.
- vilanterol/fluticasone furoate inhaled
quinidine increases toxicity of vilanterol/fluticasone furoate inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.
- vilazodone
quinidine increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase vilazodone plasma levels by 50% - Reduce daily dose to 20 mg.
- vinblastine
quinidine will increase the level or effect of vinblastine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- vincristine
quinidine will increase the level or effect of vincristine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- vincristine liposomal
quinidine will increase the level or effect of vincristine liposomal by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- vorapaxar
quinidine increases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- vorinostat
vorinostat and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- vortioxetine
quinidine increases levels of vortioxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Decrease vortioxetine dose by 50% when coadministered with strong CYP2D6 inhibitors.
- voxelotor
voxelotor will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.
Monitor Closely (272)
- acetazolamide
acetazolamide will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- albuterol
albuterol and quinidine both increase QTc interval. Use Caution/Monitor.
- alfuzosin
quinidine and alfuzosin both increase QTc interval. Use Caution/Monitor.
- aliskiren
quinidine will increase the level or effect of aliskiren by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- aluminum hydroxide
aluminum hydroxide will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- alvimopan
quinidine will increase the level or effect of alvimopan by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- amantadine
quinidine will increase the level or effect of amantadine by decreasing renal clearance. Use Caution/Monitor. Coadministration of quinine or quinidine with amantadine was shown to reduce the renal clearance of amantadine by ~30%.
- amiloride
amiloride, quinidine. Mechanism: unspecified interaction mechanism. Use Caution/Monitor. Increased risk of arrhythmias in pts. with ventricular tachycardia.
- amobarbital
amobarbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- aprepitant
aprepitant will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- arformoterol
arformoterol and quinidine both increase QTc interval. Use Caution/Monitor.
- aripiprazole
quinidine will increase the level or effect of aripiprazole by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- armodafinil
armodafinil will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
quinidine will increase the level or effect of armodafinil by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. - artemether
artemether and quinidine both increase QTc interval. Use Caution/Monitor.
- artemether/lumefantrine
artemether/lumefantrine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atazanavir
atazanavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atogepant
quinidine will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atomoxetine
quinidine will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Reduced initial doses of atomoxetine are recommended with strong CYP2D6 inhibitors.
- avapritinib
quinidine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- azithromycin
quinidine and azithromycin both increase QTc interval. Modify Therapy/Monitor Closely.
- bedaquiline
quinidine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely
- benzhydrocodone/acetaminophen
quinidine will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone [benzhydrocodone is prodrug of hydrocodone]) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.
- berotralstat
quinidine increases levels of berotralstat by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Reduced berotralstat dose to 110 mg/day when coadministered with P-gp inhibitors.
berotralstat will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.
berotralstat will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor or titrate substrate dose when berotralstat is coadministered with narrow therapeutic index drugs that are CYP3A substrates. - betrixaban
quinidine increases levels of betrixaban by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Decrease betrixaban dose to 80 mg PO once, then 40 mg PO qDay if coadministered with a P-gp inhibitor.
- blinatumomab
blinatumomab increases levels of quinidine by decreasing metabolism. Modify Therapy/Monitor Closely. Treatment initiation causes transient release of cytokines that may suppress CYP450 enzymes; highest drug-drug interaction risk is during the first 9 days of the first cycle and the first 2 days of the 2nd cycle in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index.
- bosentan
bosentan will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bosutinib
bosutinib increases levels of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
bosutinib and quinidine both increase QTc interval. Use Caution/Monitor. - brexpiprazole
quinidine will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP2D6 inhibitors. If also administered with a strong/moderate CYP3A4 inhibitor, administer a quarter of brexpiprazole dose. NOTE: In MDD clinical trials, brexpiprazole dosage was not adjusted for strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine); thus, CYP considerations are already factored into general dosing recommendations and brexpiprazole may be administered without dosage adjustment in patients with MDD.
quinidine will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP3A4 inhibitors. If also administered with a strong/moderate CYP2D6 inhibitor, administer a quarter of brexpiprazole dose. - brodalumab
brodalumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, brodalumab could normalize the formation of CYP450 enzymes. Upon initiation or discontinuation of brodalumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- budesonide
budesonide will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bupivacaine implant
quinidine, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.
- butabarbital
butabarbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- butalbital
butalbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- calcium carbonate
calcium carbonate will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Elevated quinidine plasma levels, possibly with cardiac conduction disturbances and arrhythmias, may occur.
- capecitabine
capecitabine and quinidine both increase QTc interval. Use Caution/Monitor.
- cariprazine
quinidine will increase the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors requires cariprazine dose reduction. See Dosage Modification section in drug monograph.
- cenobamate
cenobamate will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
- ceritinib
quinidine increases levels of ceritinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- chlorpromazine
quinidine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- ciprofloxacin
ciprofloxacin and quinidine both increase QTc interval. Use Caution/Monitor. Ciprofloxacin elicits minimal effects on QT interval. Caution if used in combination with other drugs known to affect QT interval or in patients with other risk factors.
- citalopram
quinidine and citalopram both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended, along with drugs that may prolong the QT interval.
- cobicistat
cobicistat will increase the level or effect of quinidine by Other (see comment). Modify Therapy/Monitor Closely. Quinidine is a substrate of CYP3A4 and P-gp, and inhibits CYP2D6 and P-gp; cobicistat is a substrate and inhibitor of both isoenzymes and a P-gp inhibitor
cobicistat will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - codeine
quinidine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
- conivaptan
conivaptan will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cortisone
cortisone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- crofelemer
crofelemer increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.
- cyclosporine
quinidine will increase the level or effect of cyclosporine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
cyclosporine will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. - dabigatran
quinidine will increase the level or effect of dabigatran by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Atrial fibrillation: Avoid coadministering dabigatran with P-gp inhibitors if CrCl <30 mL/min. DVT/PE treatment: Avoid coadministering dabigatran with P-gp inhibitors if CrCl <50 mL/min
- dabrafenib
dabrafenib will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- darifenacin
darifenacin will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- darunavir
darunavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dasatinib
dasatinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- daunorubicin
quinidine will increase the level or effect of daunorubicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- deferasirox
deferasirox will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- degarelix
degarelix and quinidine both increase QTc interval. Use Caution/Monitor.
- desflurane
desflurane and quinidine both increase QTc interval. Use Caution/Monitor.
- deutetrabenazine
quinidine will increase the level or effect of deutetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Strong CYP2D6 inhibitors increase the systemic exposure to the active dihydro-metabolites of deutetrabenazine by approximately 3-fold. Do not exceed 18 mg/dose and 36 mg/day of deutetrabenazine if coadministered with strong CYP2D6 inhibitors.
quinidine and deutetrabenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation). - dexamethasone
dexamethasone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dexfenfluramine
quinidine will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- dextroamphetamine
quinidine will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- dextroamphetamine transdermal
quinidine will increase the level or effect of dextroamphetamine transdermal by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome, particularly during dextroamphetamine initiation and after a dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and CYP2D6 inhibitor.
- dextromethorphan
quinidine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- DHEA, herbal
DHEA, herbal will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dienogest/estradiol valerate
quinidine will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.
- diltiazem
diltiazem will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
quinidine will increase the level or effect of diltiazem by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor. - donepezil
quinidine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- donepezil transdermal
quinidine, donepezil transdermal. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.
- doxorubicin
quinidine will increase the level or effect of doxorubicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- doxorubicin liposomal
quinidine will increase the level or effect of doxorubicin liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- dronedarone
dronedarone will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dulaglutide
dulaglutide, quinidine. Other (see comment). Use Caution/Monitor. Comment: Dulaglutide slows gastric emptying and may impact absorption of concomitantly administered oral medications; be particularly cautious when coadministered with drugs that have a narrow therapeutic index.
- dupilumab
dupilumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, dupilumab could normalize the formation of CYP450 enzymes. Upon initiation or discontinuation of dupilumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- duvelisib
duvelisib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.
quinidine will increase the level or effect of duvelisib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. - efavirenz
efavirenz will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- elagolix
elagolix will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
elagolix decreases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed. - eliglustat
eliglustat increases levels of quinidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.
- elranatamab
elranatamab will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elranatamab causes cytokine release syndrome (CRS) that may suppress activity of CYP enzymes, resulting in increased exposure of CYP substrates. This is more likely to occur from initiation of elranatamab step-up dosing up to 14 days after the first treatment dose and during and after CRS.
- eluxadoline
quinidine increases levels of eluxadoline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2D6 inhibitors.
eluxadoline increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution when CYP3A substrates that have a narrow therapeutic index are coadministered with eluxadoline. - elvitegravir
quinidine increases levels of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elvitegravir is a CYP3A4 substrate; if coadministered with strong CYP3A4 inhibitors may increase levels.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
- encainide
quinidine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- encorafenib
encorafenib, quinidine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.
- enzalutamide
enzalutamide will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- epcoritamab
epcoritamab, quinidine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Epcoritamab causes release of cytokines that may suppress activity of CYP enzymes, resulting in increased exposure of CYP substrates. For certain CYP substrates, minimal changes in their concentration may lead to serious adverse reactions. If needed, modify therapy as recommended in the substrate's prescribing information. .
- eslicarbazepine acetate
eslicarbazepine acetate will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- estrogens esterified
quinidine will increase the level or effect of estrogens esterified by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely.
- ethotoin
ethotoin decreases levels of quinidine by increasing metabolism. Use Caution/Monitor.
- etoposide
quinidine will increase the level or effect of etoposide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- etrasimod
etrasimod, quinidine. Either increases effects of the other by QTc interval. Modify Therapy/Monitor Closely. Transient decrease in heart rate and AV conduction delays may occur when initiating etrasimod. Owing to potential of additive effect on heart rate, etrasimod may increase risk of QT prolongation and Torsades de Pointes when coadministered with Class Ia or Class III antiarrhythmic drugs, or other drugs that prolong the QT interval. .
- etravirine
etravirine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ezogabine
ezogabine, quinidine. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.
- fedratinib
fedratinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
- ferric maltol
ferric maltol, quinidine. Either increases levels of the other by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Coadministration of ferric maltol with certain oral medications may decrease the bioavailability of either ferric maltol and some oral drugs. For oral drugs where reductions in bioavailability may cause clinically significant effects on its safety or efficacy, separate administration of ferric maltol from these drugs. Duration of separation may depend on the absorption of the medication concomitantly administered (eg, time to peak concentration, whether the drug is an immediate or extended release product).
- fesoterodine
quinidine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- fexofenadine
quinidine will increase the level or effect of fexofenadine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- finerenone
quinidine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.
- floxuridine
floxuridine and quinidine both increase QTc interval. Use Caution/Monitor.
- fludrocortisone
fludrocortisone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fluphenazine
quinidine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- fluticasone furoate
quinidine will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure
- fluticasone inhaled
quinidine will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure
- fluvoxamine
quinidine will increase the level or effect of fluvoxamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- fosamprenavir
fosamprenavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fosaprepitant
fosaprepitant will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fosphenytoin
fosphenytoin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
fosphenytoin decreases levels of quinidine by increasing metabolism. Use Caution/Monitor. - fostamatinib
fostamatinib will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.
- fostemsavir
quinidine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.
- galantamine
quinidine will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- gefitinib
quinidine increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.
- gemtuzumab
quinidine and gemtuzumab both increase QTc interval. Use Caution/Monitor.
- gepirone
gepirone and quinidine both increase QTc interval. Modify Therapy/Monitor Closely.
- glecaprevir/pibrentasvir
quinidine will increase the level or effect of glecaprevir/pibrentasvir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
glecaprevir/pibrentasvir will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. - glofitamab
glofitamab, quinidine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Glofitamab causes release of cytokines that may suppress activity of CYP enzymes, resulting in increased exposure of CYP substrates. For certain CYP substrates, minimal changes in their concentration may lead to serious adverse reactions. If needed, modify therapy as recommended in the substrate's prescribing information. .
- glycerol phenylbutyrate
glycerol phenylbutyrate will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Glycerol phenylbutyrate is a weak inducer of CYP3A4. Monitor for decreased efficacy of CYP3A4 substrates that have a narrow therapeutic index.
- grapefruit
grapefruit will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- griseofulvin
griseofulvin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- guselkumab
guselkumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, normalizing the formation of CYP450 enzymes. Upon initiation or discontinuation of guselkumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- hawthorn
hawthorn increases effects of quinidine by pharmacodynamic synergism. Use Caution/Monitor.
- henbane
henbane, quinidine. unspecified interaction mechanism. Use Caution/Monitor. Combination not recommended by British Herbal Medicine Association.
- hydrochlorothiazide
quinidine will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- hydrocodone
quinidine will increase the level or effect of hydrocodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.
- hydrocortisone
hydrocortisone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- iloperidone
iloperidone increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.
- incobotulinumtoxinA
quinidine, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.
- indacaterol, inhaled
indacaterol, inhaled, quinidine. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.
- indinavir
indinavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isavuconazonium sulfate
quinidine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
isavuconazonium sulfate will increase the level or effect of quinidine by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. - isoflurane
isoflurane and quinidine both increase QTc interval. Use Caution/Monitor.
- isoniazid
isoniazid will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- istradefylline
istradefylline will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.
istradefylline will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates. - ivacaftor
ivacaftor increases levels of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Ivacaftor and its M1 metabolite has the potential to inhibit P-gp; may significantly increase systemic exposure to sensitive P-gp substrates with a narrow therapeutic index.
- ixekizumab
ixekizumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, ixekizumab could normalize the formation of CYP450 enzymes. Upon initiation or discontinuation of ixekizumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- lacosamide
quinidine, lacosamide. Either increases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP3A4 inhibitors.
- lapatinib
lapatinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lemborexant
quinidine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.
- lenvatinib
quinidine and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.
- letermovir
letermovir increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levomilnacipran
quinidine will increase the level or effect of levomilnacipran by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed 80 mg/day of levomilnacipran when coadministered with strong CYP3A4 inhibitors
- lofexidine
quinidine will increase the level or effect of lofexidine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Concomitant use of lofexidine with strong CYP2D6 inhibitors may increase lofexidine plasma levels. Monitor for symptoms of orthostasis and bradycardia if coadministered with a CYP2D6 inhibitor. Consider lofexidine dose reduction.
quinidine and lofexidine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended. - lomitapide
lomitapide increases levels of quinidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.
- lonafarnib
lonafarnib will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Lonafarnib is a weak P-gp inhibitor. Monitor for adverse reactions if coadministered with P-gp substrates where minimal concentration changes may lead to serious or life-threatening toxicities. Reduce P-gp substrate dose if needed.
- lonapegsomatropin
lonapegsomatropin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates
- loratadine
quinidine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
quinidine will increase the level or effect of loratadine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. - lumacaftor/ivacaftor
quinidine increases levels of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A inhibitors do not impact lumacaftor exposure, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg q12hr (the approved dose of ivacaftor monotherapy). Therefore, no dose adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking lumacaftor/ivacaftor. However, when initiating lumacaftor/ivacaftor in patients taking strong CYP3A inhibitors, reduce the dose to 1 tablet daily (lumacaftor 200 mg/ivacaftor 125 mg total daily dose) for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose. No dose adjustment is required for moderate or weak CYP3A4 inhibitors.
- lumefantrine
lumefantrine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- maraviroc
quinidine will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decrease maraviroc dose to 150 mg BID when coadministered with strong CYP3A4 inhibitors
- marijuana
marijuana will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- medroxyprogesterone
quinidine will increase the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternative if available.
- memantine
quinidine will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- metformin
quinidine will increase the level or effect of metformin by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- methyclothiazide
quinidine will increase the level or effect of methyclothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- methylprednisolone
methylprednisolone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- metronidazole
metronidazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- miconazole vaginal
miconazole vaginal will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- midazolam intranasal
quinidine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.
- midodrine
quinidine will increase the level or effect of midodrine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- mitotane
mitotane decreases toxicity of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.
- nafcillin
nafcillin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- naldemedine
quinidine increases levels of naldemedine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with P-gp inhibitors.
- nelfinavir
nelfinavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- netupitant/palonosetron
quinidine will increase the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Netupitant is mainly metabolized by CYP3A4; no dosage adjustment is required
- nevirapine
nevirapine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nifedipine
nifedipine will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
nifedipine decreases levels of quinidine by increasing elimination. Use Caution/Monitor.
quinidine increases levels of nifedipine by decreasing metabolism. Use Caution/Monitor. - nintedanib
quinidine increases levels of nintedanib by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. If nintedanib adverse effects occur, management may require interruption, dose reduction, or discontinuation of therapy .
- ofloxacin
quinidine will increase the level or effect of ofloxacin by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- oliceridine
quinidine will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
- olodaterol inhaled
quinidine and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. Drugs that prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmias
- omaveloxolone
omaveloxolone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Omaveloxolone may reduce systemic exposure of sensitive CYP3A4 substrates. Check prescribing information of substrate if dosage modification is needed.
- ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)
ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution is warranted and therapeutic concentration monitoring (if available) is recommended for antiarrhythmics when coadministered with Viekira Pak
- oritavancin
oritavancin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Oritavancin is a weak CYP3A4 inducer; caution if coadministered with CYP3A4 substrates that have a narrow therapeutic index
- osilodrostat
osilodrostat and quinidine both increase QTc interval. Use Caution/Monitor.
- osimertinib
osimertinib and quinidine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.
- ospemifene
quinidine increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- oxaliplatin
oxaliplatin will increase the level or effect of quinidine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.
- oxcarbazepine
oxcarbazepine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- oxycodone
quinidine decreases effects of oxycodone by decreasing metabolism. Use Caution/Monitor. Decreased conversion of hydrocodone to active metabolite morphine.
- ozanimod
ozanimod and quinidine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.
- palbociclib
palbociclib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The dose of sensitive CYP3A substrates with a narrow therapeutic index may need to be reduced if coadministered with palbociclib
- panobinostat
quinidine increases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce panobinostat starting dose to 10 mg if coadministered with strong CYP3A4 inhibitors.
- paroxetine
quinidine will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Monitor patients for signs of paroxetine toxicity. Paroxetine doses may need to be reduced.
- pasireotide
quinidine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.
- patiromer
patiromer will decrease the level or effect of quinidine by cation binding in GI tract. Modify Therapy/Monitor Closely. Separate administration by at least 3 hr from patiromer
- pazopanib
quinidine and pazopanib both increase QTc interval. Modify Therapy/Monitor Closely.
- pentobarbital
pentobarbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- perhexiline
quinidine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- perphenazine
quinidine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- phenobarbital
phenobarbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- phenytoin
phenytoin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
phenytoin decreases levels of quinidine by increasing metabolism. Use Caution/Monitor. - pirtobrutinib
pirtobrutinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Pirtobrutinib (a CYP3A4 inhibitor) may increase plasma concentrations of sensitive CYP3A4 substrate which may increase the risk of adverse reactions related to these substrates.
- pitolisant
quinidine will increase the level or effect of pitolisant by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If coadministered with strong CYP2D6 inhibitors, initiate pitolisant at 8.9 mg/day and increase after 7 days to maximum of 17.8 mg/day. For patients currently taking pitolisant, reduce pitolisant dose by half upon initiating strong CYP2D6 inhibitors.
pitolisant will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Pitolisant is a borderline/weak inducer of CYP3A4. Monitor sensitive CYP3A4 substrates for reduced effectiveness if coadministered. - ponatinib
ponatinib increases levels of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- pramipexole
quinidine will increase the level or effect of pramipexole by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- prednisone
prednisone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- primidone
primidone will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- prochlorperazine
quinidine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- promazine
quinidine will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- promethazine
quinidine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- quetiapine
quetiapine, quinidine. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.
- quinine
quinidine will increase the level or effect of quinine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
quinidine and quinine both increase QTc interval. Use Caution/Monitor. - quinupristin/dalfopristin
quinupristin/dalfopristin will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- quizartinib
quizartinib, quinidine. Either increases effects of the other by QTc interval. Modify Therapy/Monitor Closely. Monitor patients more frequently with ECG if coadministered with QT prolonging drugs.
- ribociclib
ribociclib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution if ribociclib is coadministered with sensitive CYP3A4 substrates that have a narrow therapeutic index. Dose reduction for sensitive CYP3A4 substrates may be needed.
- rifapentine
rifapentine will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rifaximin
quinidine increases levels of rifaximin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- rilpivirine
rilpivirine increases toxicity of quinidine by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsade de Pointes.
- rimabotulinumtoxinB
quinidine, rimabotulinumtoxinB. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.
- risperidone
quinidine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- ritlecitinib
ritlecitinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Ritlecitinib inhibits CYP3A4 substrates; coadministration increases AUC and peak plasma concentration sensitive substrates, which may increase risk of adverse reactions. Additional monitoring and dosage adjustment may be needed in accordance with product labeling of CYP3A substrates.
- ritonavir
ritonavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rivaroxaban
quinidine increases levels of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Patients with renal impairment receiving rivaroxaban with drugs that are combined P-gp and weak or moderate CYP3A4 inhibitors may have significant increases in exposure compared with patients with normal renal function and no inhibitor use, since both pathways of rivaroxaban elimination are affected. Since these increases may increase bleeding risk, use rivaroxaban in this situation only if the potential benefit justifies the potential risk.
- ropeginterferon alfa 2b
ropeginterferon alfa 2b will increase the level or effect of quinidine by Other (see comment). Use Caution/Monitor. Certain proinflammatory cytokines, including interferons, can suppress CYP450 enzymes resulting in increased exposures of some CYP substrates. Therefore, monitor patients who are receiving concomitant drugs that are CYP450 substrates with a narrow therapeutic index from toxicities to such drugs.
- rucaparib
rucaparib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.
- rufinamide
rufinamide will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- sarecycline
sarecycline will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.
- sarilumab
sarilumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.
- saxagliptin
quinidine will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit saxagliptin dose to 2.5 mg/day when coadministered with strong CYP3A4 inhibitors
- schisandra
schisandra will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- secobarbital
secobarbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- secukinumab
secukinumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, secukinumab could normalize the formation of CYP450 enzymes. Upon initiation or discontinuation of secukinumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- selpercatinib
selpercatinib increases toxicity of quinidine by QTc interval. Use Caution/Monitor.
- sevelamer
sevelamer decreases levels of quinidine by increasing elimination. Use Caution/Monitor.
- sevoflurane
sevoflurane and quinidine both increase QTc interval. Use Caution/Monitor.
- siltuximab
siltuximab, quinidine. Other (see comment). Use Caution/Monitor. Comment: CYP450 activity in the liver is down regulated by infection and inflammation stimuli including cytokines (eg, IL-6); inhibition of IL-6 by siltuximab may restore CYP450 enzymatic activity; caution if coadministered with CYP substrates that have a narrow therapeutic index.
- sodium bicarbonate
sodium bicarbonate will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Elevated quinidine plasma levels, possibly with cardiac conduction disturbances and arrhythmias, may occur.
- sodium citrate/citric acid
sodium citrate/citric acid will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Elevated quinidine plasma levels, possibly with cardiac conduction disturbances and arrhythmias, may occur.
- sodium lactate
sodium lactate will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- sodium sulfate/?magnesium sulfate/potassium chloride
sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of quinidine by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .
- sodium sulfate/potassium sulfate/magnesium sulfate
sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of quinidine by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .
- sofosbuvir/velpatasvir
sofosbuvir/velpatasvir increases levels of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Velpatasvir inhibits CYP3A4. Caution if coadministered with drugs with narrow therapeutics indexes.
- solifenacin
solifenacin and quinidine both increase QTc interval. Use Caution/Monitor.
- somapacitan
somapacitan will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates
- somatrogon
somatrogon will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates
- somatropin
somatropin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates
- sorafenib
sorafenib and quinidine both increase QTc interval. Use Caution/Monitor.
- stiripentol
stiripentol, quinidine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
stiripentol will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol. - sulfamethoxazole
quinidine will increase the level or effect of sulfamethoxazole by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- talazoparib
quinidine will increase the level or effect of talazoparib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Talazoparib is a P-glycoprotein (P-gp) substrate; coadministration with P-gp inhibitors may increase talazoparib systemic exposure.
- talquetamab
talquetamab will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Talquetamab causes cytokine release syndrome (CRS) that may suppress activity of CYP enzymes, resulting in increased exposure of CYP substrates. This is more likely to occur from initiation of talquetamab step-up dosing up to 14 days after the first treatment dose and during and after CRS.
- tamoxifen
quinidine decreases effects of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.
- tamsulosin
quinidine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- tasimelteon
quinidine will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tazemetostat
tazemetostat will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
quinidine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - teclistamab
teclistamab will increase the level or effect of quinidine by altering metabolism. Use Caution/Monitor. Teclistamab causes release of cytokines that may suppress activity of CYP450 enzymes, resulting in increased exposure of CYP substrates. Monitor for increased concentrations or toxicities of sensitive CYP substrates. Adjust dose of CYP substrate drug as needed.
- tecovirimat
tecovirimat will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.
- teduglutide
teduglutide increases levels of quinidine by Other (see comment). Use Caution/Monitor. Comment: Teduglutide may increase absorption of concomitant PO medications; caution with with drugs requiring titration or those with a narrow therapeutic index; dose adjustment may be necessary.
- telotristat ethyl
telotristat ethyl will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Telotristat ethyl induces CYP3A4 and may reduce systemic exposure of sensitive CYP3A4 substrates. Monitor for suboptimal efficacy and consider increasing the dose of the CYP3A4 substrate.
- teniposide
quinidine will increase the level or effect of teniposide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- tenofovir DF
tenofovir DF, quinidine. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.
- tetrabenazine
quinidine increases effects of tetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Decrease tetrabenazine dose by 50% when coadministered with strong CYP2D6 inhibitors.
- tinidazole
quinidine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tobramycin inhaled
tobramycin inhaled and quinidine both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity
- tolterodine
quinidine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- topiramate
topiramate will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tramadol
quinidine decreases effects of tramadol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Decreased conversion of tramadol to active metabolite.
quinidine decreases effects of tramadol by decreasing metabolism. Use Caution/Monitor. Decreased conversion of tramadol to active metabolite. - triamterene
quinidine will increase the level or effect of triamterene by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- triclabendazole
triclabendazole and quinidine both increase QTc interval. Use Caution/Monitor.
- trifluoperazine
quinidine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- trimethoprim
quinidine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
- trofinetide
trofinetide will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor CYP3A4 substrates for which a small increase in plasma concentration may lead to serious toxicities if coadministered with trofinetide (a weak CYP3A4 inhibitor).
- tropisetron
quinidine will increase the level or effect of tropisetron by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- tucatinib
tucatinib will increase the level or effect of quinidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.
- turmeric
turmeric will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- umeclidinium bromide/vilanterol inhaled
quinidine will increase the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vilanterol is a CYP3A4 substrate; coadministration with potent CYP3A4 inhibitors may increase systemic exposure
- ustekinumab
ustekinumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, normalizing the formation of CYP450 enzymes. Upon initiation or discontinuation of ustekinumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- valbenazine
quinidine will increase the level or effect of valbenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Consider reducing valbenazine dose based on tolerability if coadministered with a strong CYP2D6 inhibitor.
- vemurafenib
vemurafenib and quinidine both increase QTc interval. Modify Therapy/Monitor Closely. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended. Quinidine may also increase vemurafenib levels.
- verapamil
verapamil will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
quinidine will increase the level or effect of verapamil by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor. - vilanterol/fluticasone furoate inhaled
quinidine will increase the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Fluticasone furoate and vilanterol are both CYP3A4 substrates; coadministration with potent CYP3A4 inhibitors may increase systemic exposure
- voclosporin
voclosporin, quinidine. Either increases effects of the other by QTc interval. Use Caution/Monitor.
- vonoprazan
vonoprazan will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Vonoprazan is weak CYP3A inhibitor. Caution with sensitive CYP3A substrates.
- warfarin
quinidine will increase the level or effect of warfarin by decreasing metabolism. Use Caution/Monitor. Cinchona alkaloids, including quinine and quinidine, may increase anticoagulant effect of vitamin K antagonists by inhibiting hepatic synthesis of vitamin K-dependent coagulation proteins.
- zafirlukast
zafirlukast will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
Minor (25)
- acetazolamide
acetazolamide will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ambrisentan
quinidine will increase the level or effect of ambrisentan by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.
- anastrozole
anastrozole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- antithrombin alfa
quinidine increases effects of antithrombin alfa by decreasing metabolism. Minor/Significance Unknown.
- antithrombin III
quinidine increases effects of antithrombin III by decreasing metabolism. Minor/Significance Unknown.
- argatroban
quinidine increases effects of argatroban by decreasing metabolism. Minor/Significance Unknown.
- atracurium
quinidine increases effects of atracurium by pharmacodynamic synergism. Minor/Significance Unknown.
- bemiparin
quinidine increases effects of bemiparin by decreasing metabolism. Minor/Significance Unknown.
- bivalirudin
quinidine increases effects of bivalirudin by decreasing metabolism. Minor/Significance Unknown.
- cisatracurium
quinidine increases effects of cisatracurium by pharmacodynamic synergism. Minor/Significance Unknown.
- cyclophosphamide
cyclophosphamide will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- dalteparin
quinidine increases effects of dalteparin by decreasing metabolism. Minor/Significance Unknown.
- enoxaparin
quinidine increases effects of enoxaparin by decreasing metabolism. Minor/Significance Unknown.
- fondaparinux
quinidine increases effects of fondaparinux by decreasing metabolism. Minor/Significance Unknown.
- heparin
quinidine increases effects of heparin by decreasing metabolism. Minor/Significance Unknown.
- larotrectinib
larotrectinib will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- lily of the valley
quinidine, lily of the valley. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown.
- onabotulinumtoxinA
quinidine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Minor/Significance Unknown.
- pancuronium
quinidine increases effects of pancuronium by pharmacodynamic synergism. Minor/Significance Unknown.
- phenindione
quinidine increases effects of phenindione by decreasing metabolism. Minor/Significance Unknown.
- protamine
quinidine increases effects of protamine by decreasing metabolism. Minor/Significance Unknown.
- rapacuronium
quinidine increases effects of rapacuronium by pharmacodynamic synergism. Minor/Significance Unknown.
- rocuronium
quinidine increases effects of rocuronium by pharmacodynamic synergism. Minor/Significance Unknown.
- succinylcholine
quinidine increases effects of succinylcholine by pharmacodynamic synergism. Minor/Significance Unknown.
- vecuronium
quinidine increases effects of vecuronium by pharmacodynamic synergism. Minor/Significance Unknown.
Adverse Effects
>10%
Diarrhea (35%)
Stomach cramping (22%)
Lightheadedness (15%)
QTc prolongation (modest prolongation common; excessive prolongation rare & indicates toxicity) (>10%)
Anorexia (>10%)
Bitter taste (>10%)
Diarrhea (>10%)
Upper GI distress (>10%)
Nausea (>10%)
Vomiting (>10%)
1-10%
Syncope (1-8%)
Palpitation (7%), new or worsened arrhythmias (proarrhythmic effect),
Headache (7%)
Fatigue (7%)
Angina (6%)
Rash (5%)
Weakness (5%)
Sleep disturbance (3%)
Nervousness (2%)
Tremor (2%)
Incoordination (1%)
Blurred vision
Tinnitus
Wheezing
Frequency Not defined
Hypotension
Hepatotoxicity
Arthralgia
Diplopia
Night blindness
Hypersensitivity reactions (eg, fever, hemolytic/aplastic anemia, respiratory arrest, agranulocytosis)
Systemic lupus erythematosus may occur if taking quinidine for prolonged period of time
Warnings
Black Box Warnings
In patients with various non-life-threatening ventricular arrhythmias, mortality associated with use of quinidine reported to be consistently greater than that associated with use of any of a variety of alternative antiarrhythmic; mortality risk increases with structural heart disease.
In the case of quinidine used to prevent or defer recurrence of atrial flutter/fibrillation, the drug may increase mortality
Contraindications
Hypersensitivity to quinidine or cinchona alkaloids
Myasthenia gravis, thrombocytopenia or developed thrombocytopenic purpura during prior therapy with quinidine or quinine
Heart block >1st degree
Idioventricular conduction delays, including patients in complete atrioventricular block (except when artificial pacemaker present)
Patients adversely affected by anticholinergic activity
Drugs or conditions that prolong QT interval
Cautions
Use caution in acute rheumatic fever, acute thyrotoxicosis, CHF, subacute bacterial endocarditis, syncope
Electrolyte imbalances due to severe N/V, diarrhea, eating disorders may occur; use caution
IV administration requires continuous cardiac & blood pressure monitoring
Dose should be adjusted within range to achieve desired therapeutic effects within therapeutic plasma concentration and in absence of toxic SE
Avoid grapefruit juice
Very high dosages may induce abortion in pregnant women due to oxytocic effect
Extended-release not recommended in children
When quinidine is administered to patients with atrial flutter/fibrillation, the desired pharmacologic reversion to sinus rhythm may (rarely) be preceded by a slowing of atrial rate with a consequent increase in rate of beats conducted to ventricles; the resulting ventricular rate may be very high (greater than 200 beats per minute) and poorly tolerated; this hazard may be decreased if partial atrioventricular block is achieved prior to initiation of quinidine therapy, using conduction-reducing drugs such as digitalis, verapamil, diltiazem, or a β-receptor blocking agent
In patients with sick sinus syndrome, quinidine has been associated with marked sinus node depression and bradycardia
Renal or hepatic dysfunction causes the elimination of quinidine to be slowed, while congestive heart failure causes a reduction in quinidine's apparent volume of distribution. Any of these conditions can lead to quinidine toxicity if dosage is not appropriately reduced
Because quinidine opposes atrial and A-V nodal effects of vagal stimulation, physical or pharmacological vagal maneuvers undertaken to terminate paroxysmal supraventricular tachycardia may be ineffective in patients receiving quinidine
In patients without implanted pacemakers who are at high risk of complete atrioventricular block(eg, those with digitalis intoxication, second-degree atrioventricular block, or severe intraventricular conduction defects), quinidine should be used only with caution
Proarrhythmic effects
- As with other drugs (including all other Class Ia antiarrhythmics), quinidine prolongs QT interval, and can lead to torsades de pointes, a life-threatening ventricular arrhythmia; the risk of torsades is increased by bradycardia, hypokalemia, hypomagnesemia, or high serum levels of quinidine, but may appear in absence of any of these risk factors
- The best predictor of this arrhythmia appears to be the length of QTc interval; quinidine should be used with extreme care in patients who have preexisting long-QT syndromes, who have histories of torsades de pointes of any cause, or who have previously responded to quinidine (or other drugs that prolong ventricular repolarization) with marked lengthening of the QT c interval
Thrombocytopenia
- Quinidine-induced thrombocytopenia is an immune-mediated disorder characterized by a drug-dependent antibody that is itself nonreactive, but when soluble drug is present at pharmacologic concentrations, binds tightly to specific platelet membrane glycoproteins, causing platelet destruction
- Serologic testing for quinidine-specific antibody is commercially available and may be useful for identifying specific cause of thrombocytopenia in individual cases; testing is important because a patient with quinidine-dependent antibodies should not be re-exposed to quinidine
- Typically, a patient with immune thrombocytopenia will have taken drug for about 1 week or intermittently over a longer period of time (possibly years) before presenting with petechiae or bruising
- Systemic symptoms, such as lightheadedness, chills, fever, nausea, and vomiting, often may precede bleeding events; thrombocytopenia may be severe; patients should have risk/benefit reevaluated in order to continue treatment with quinidine; if drug is stopped, symptoms usually resolve within 1 or 2 days and platelet count returns to normal in less than 1 week
- If quinidine is not stopped, there is a risk of fatal hemorrhage; the onset of thrombocytopenia may be more rapid upon re-exposure
Drug interaction overview
- Interactions with coadministered drugs can alter serum concentration and activity of quinidine, leading either to toxicity or to lack of efficacy if dose of quinidine is not appropriately modified
- Diltiazem significantly decreases clearance and increases t1/2 of quinidine, but quinidine does not alter the kinetics of diltiazem
- Drugs that alkalinize urine (carbonic-anhydrase inhibitors, sodium bicarbonate, thiazide diuretics) reduce renal elimination of quinidine
- By pharmacokinetic mechanisms not well understood, quinidine levels are increased by coadministration of amiodarone or cimetidine
- Very rarely, and again by mechanisms, not understood, quinidine levels are decreased by coadministration of nifedipine
- Hepatic elimination of quinidine may be accelerated by coadministration of drugs ( phenobarbital, phenytoin, rifampin) that induce production of cytochrome P450 IIIA4; perhaps because of competition for P450 IIIA4 metabolic pathway, quinidine levels rise when ketoconazole is coadministered
- Coadministration of propranolol usually does not affect quinidine pharmacokinetics, but in some studies, the β-blocker appeared to cause increases in peak serum levels of quinidine, decreases in quinidine's volume of distribution, and decreases in total quinidine clearance
- The effects (if any) of coadministration of other beta-blockers on quinidine pharmacokinetics have not been adequately studied; hepatic clearance of quinidine is significantly reduced during coadministration of verapamil, with corresponding increases in serum levels and half-life
- The rate and extent of quinidine absorption may be affected by changes in dietary salt intake; a decrease in dietary salt intake may lead to an increase in plasma quinidine concentrations
Pregnancy & Lactation
Pregnancy
There are no adequate and well-controlled studies in pregnant women
Animal reproductive studies have not been conducted
Lactation
Lactation: crosses into breast milk, use extreme caution (AAP Committee states compatible with nursing)
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Class IA (membrane stabilizing) antiarrhythmic agent; inhibits recovery after repolarization resulting in decreasing myocardial excitability & conduction velocity
Direct membrane depressant that decreases conduction velocity, prolongs refractoriness, decreases automaticity and reduces repolarization abnormalities
Absorption
Bioavailability: Sulfate 70%; gluconate 70-80%
Peak Plasma Time: 2 hr (sulfate); 3-6 hr (gluconate)
Onset: PO: 1-3 hr
Duration: 6-8 hr
Distribution
Vd: 2-3 L/kg (adults); 0.5 L/kg (heart failure)
Protein Bound: 80-88% (adults); 50-70% (newborns)
Metabolism
Metabolism: Liver via hepatic P450 enzyme CYP3A4
Metabolites: 3-hydroxyquinidine and 2-quinidinone (some have antiarrhythmic effects)
Enzymes inhibited: CYP2D6
Elimination
Half-Life: 6-8 hr (adults); 3-4hr (children)
Clearance: 3-5 mL/min/kg (adults); 1-2.5 mL/min/kg (children)
Excretion: Urine (15-25%); feces (5%)
Dialyzable: HD: Yes; PD: No
Administration
Oral Administration
May take with or without food
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
quinidine gluconate oral - | 324 mg tablet | ![]() |
Copyright © 2010 First DataBank, Inc.
Patient Handout
quinidine gluconate oral
QUINIDINE - ORAL
(KWIN-i-deen)
COMMON BRAND NAME(S): Quinidex
WARNING: Before taking this drug for treatment of an irregular heartbeat, you should discuss your risks and benefits of treatment with your doctor or pharmacist. This drug should be used only in carefully selected patients. Many heart drugs like quinidine (antiarrhythmics) are very effective, but they can rarely cause new serious (possibly fatal) irregular heartbeats.
USES: This medication is used to treat or prevent many types of irregular heartbeats (heart arrhythmias such as atrial fibrillation). Quinidine can greatly improve your ability to perform normal activities by decreasing the number of irregular heartbeats you have. However, it may not stop all your irregular heartbeats completely. It works by blocking abnormal heartbeat signals.Before and while you are using quinidine, your doctor may prescribe other medications (such as "blood thinners"/anticoagulants such as warfarin, beta blockers such as metoprolol) to shrink any blood clots in the heart and to slow your pulse.
HOW TO USE: Before starting this drug, the manufacturer recommends that you take a test dose (usually a smaller amount than your regular dose) to determine whether you are allergic to it. Consult your doctor or pharmacist for details.Take this medication by mouth with or without food with a full glass of liquid (8 ounces/240 milliliters) as directed by your doctor. This medication is best taken on an empty stomach, but taking it with food may help decrease stomach upset. Do not lie down for at least 10 minutes after taking this medication.Do not crush or chew extended-release tablets. Doing so can release all of the drug at once, increasing the risk of side effects. Swallow the tablets whole.There are different brands and forms of this medication available. Not all have identical effects. Do not change quinidine products without talking to your doctor or pharmacist.Dosage is based on your medical condition and response to treatment. If you are taking regular-release quinidine for an irregular heartbeat, the manufacturer recommends that you take no more than 4 grams daily.Avoid eating grapefruit or drinking grapefruit juice while using this medication unless your doctor or pharmacist says you may do so safely. Grapefruit can increase the chance of side effects with this medicine. Ask your doctor or pharmacist for more details.Avoid large changes in your dietary salt intake while being treated with this medication unless your doctor instructs you otherwise. The amount of salt in your diet may affect the amount of quinidine absorbed by your system. Consult your doctor or pharmacist for more details.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.Tell your doctor if your condition does not improve or if it worsens.
SIDE EFFECTS: Diarrhea, nausea, vomiting, loss of appetite, stomach pain/cramps, or a burning feeling in throat or chest (such as heartburn) may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: nausea/vomiting that doesn't stop, vision changes, eye pain, muscle pain, signs of low blood sugar (such as unusual sweating, shakiness), signs of infection (such as sore throat that doesn't go away, fever, chills), easy bruising/bleeding, extreme tiredness, dark urine, yellowing eyes/skin, aching/swollen joints.Get medical help right away if you have any very serious side effects, including: severe dizziness, fainting, sudden change in heartbeat (faster/slower/more irregular).A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.One type of reaction (cinchonism) can occur after even a single dose of this drug. Contact your doctor of pharmacist promptly if you notice symptoms such as ringing in the ears, sudden hearing problems, headache, blurred vision, confusion. Your dosage may need to be adjusted.Certain long-acting brands of quinidine may appear as a whole tablet in the stool. This is the empty shell left after the medicine has been absorbed by the body. It is harmless.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking quinidine, tell your doctor or pharmacist if you are allergic to it; or to quinine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: certain types of heart disease (such as incomplete or complete heart block without an artificial pacemaker, torsades-type irregular heartbeats, digitalis toxicity), very low blood pressure, history of easy bruising/bleeding (thrombocytopenic purpura) with use of quinine or quinidine, severe muscle weakness (myasthenia gravis), kidney disease, liver disease, a certain blood disorder (G6PD deficiency), asthma, current infection with fever.Quinidine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that require immediate medical attention right away.The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using quinidine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using quinidine safely.This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor that you are using this medication.Older adults may be more sensitive to the side effects of this drug, especially dizziness and QT prolongation (see above).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This medication passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: See also the How to Use section.Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: large amounts of antacids (such as sodium bicarbonate), arbutamine, aripiprazole, atomoxetine, etravirine, fingolimod, fosamprenavir, loperamide, certain macrolide antibiotics (such as erythromycin, clarithromycin), phenytoin, propafenone, quinupristin/dalfopristin, rifamycins (such as rifampin, rifabutin).Other medications can affect the removal of quinidine from your body, which may affect how quinidine works. Examples include cobicistat, mifepristone, ritonavir, certain azole antifungals (including fluconazole, itraconazole, ketoconazole, posaconazole, voriconazole), certain protease inhibitors (such as nelfinavir, tipranavir), among others.This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include aliskiren, codeine, digoxin, mefloquine, tricyclic antidepressants (such as desipramine, imipramine), among others.Many drugs besides quinidine may affect the heart rhythm (QT prolongation), including artemether/lumefantrine, ranolazine, toremifene, antiarrhythmic drugs (such as amiodarone, disopyramide, dofetilide, dronedarone, ibutilide, procainamide, sotalol), antipsychotics (such as pimozide, thioridazine, ziprasidone), certain quinolone antibiotics (grepafloxacin, sparfloxacin), among others.Quinidine is very similar to quinine. Do not use medications containing quinine while using quinidine.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe dizziness/fainting, hallucinations, seizures.
NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, liver/kidney function, quinidine blood levels, EKG) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.
MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).
Information last revised April 2023. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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