mexiletine (Rx)

Brand and Other Names:

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

capsule

  • 150mg
  • 200mg
  • 250mg

Ventricular Arrhythmias (Life-Threatening)

Initial: 200 mg PO q8hr; may load with 400 mg followed by 200 mg PO q8hr if necessary for rapid control of ventricular arrhythmia

Dose range: 200-300 mg PO q8hr

May increase to 400 mg q8hr; not to exceed 1200 mg/day

Take with food or antacid

Therapeutic range: 0.5-2 mg/L

Organ Transplant Rejection (Orphan)

Prevention of acute and chronic rejection in patients who have received solid organ transplants

Orphan indication sponsor

  • James W Williams, MD; Rush-Presbyterian-St. Luke's Medical Ctr, Dept o, 1653 West Congress Parkway; Chicago, IL 60612-3833

Myotonia (Orphan)

Treatment of nondystrophic myotonia

Orphan indication sponsor

  • University of Rochester Medical Center; 1351 Mt. Hope Ave, Suite 203; Rochester, NY 14620

Renal Impairment

CrCl<10 mL/min: 50-75% of normal dose

Hepatic Impairment

Liver impairment or CHF: 25-30% of normal dose

Not FDA approved

Usual dose for arrhythmias: 2.5-5 mg/kg PO q8hr

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Interactions

Interaction Checker

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            Contraindicated (2)

            • dofetilide

              mexiletine, dofetilide. Either increases effects of the other by pharmacodynamic synergism. Contraindicated. Additive cardiac effects.

            • fezolinetant

              mexiletine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

            Serious - Use Alternative (16)

            • alosetron

              mexiletine will increase the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

            • artemether/lumefantrine

              artemether/lumefantrine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • duloxetine

              mexiletine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

            • fluoxetine

              fluoxetine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • fluvoxamine

              fluvoxamine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

            • givosiran

              givosiran will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP1A2 substrates with givosiran. If unavoidable, decrease the CYP1A2 substrate dosage in accordance with approved product labeling.

            • leniolisib

              leniolisib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid leniolisib with CYP1A2 substrates that have a narrow therapeutic index

            • lumefantrine

              lumefantrine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • melatonin

              mexiletine will increase the level or effect of melatonin by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of melatonin with strong CYP1A2 inhibitors

            • paroxetine

              paroxetine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • pefloxacin

              pefloxacin will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

            • pimozide

              mexiletine, pimozide. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of prolonged QTc interval.

            • pirfenidone

              mexiletine will increase the level or effect of pirfenidone by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Use of strong CYP1A2 inhibitors should be discontinued before initiating pirfenidone and avoided during treatment; if strong CYP1A2 inhibitors are the only drug of choice, dosage reductions are recommended

            • pomalidomide

              mexiletine increases levels of pomalidomide by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

            • quinidine

              quinidine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • tizanidine

              mexiletine will increase the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

            Monitor Closely (100)

            • abiraterone

              abiraterone increases levels of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

            • acetazolamide

              acetazolamide will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • aluminum hydroxide

              aluminum hydroxide will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • amiodarone

              amiodarone will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • amobarbital

              amobarbital will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • armodafinil

              armodafinil will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • asenapine

              asenapine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • bendamustine

              mexiletine increases levels of bendamustine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Decreased conversion of bendamustine to active metabolites. Concentration of active metabolites of bendamustine may be decreased.

            • bupropion

              bupropion will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • butabarbital

              butabarbital will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • butalbital

              butalbital will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • calcium carbonate

              calcium carbonate will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • cannabidiol

              cannabidiol, mexiletine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP1A2 induction and inhibition with the coadministration of CYP1A2 substrates and cannabidiol, consider reducing dosage adjustment of CYP1A2 substrates as clinically appropriate.

            • carbamazepine

              carbamazepine will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • celecoxib

              celecoxib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • chloroquine

              chloroquine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • cigarette smoking

              cigarette smoking will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • cimetidine

              cimetidine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

              cimetidine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • ciprofloxacin

              ciprofloxacin will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Mexiletine concentrations may be elevated and may produce an increase in therapeutic and adverse reactions.

            • clobazam

              clobazam will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.

            • clomipramine

              mexiletine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • clozapine

              mexiletine will increase the level or effect of clozapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • cobicistat

              cobicistat will increase the level or effect of mexiletine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clinical monitoring is recommended upon coadministration with antiarrhythmics.

            • darifenacin

              darifenacin will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • darunavir

              darunavir will increase the level or effect of mexiletine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clinical monitoring is recommended upon coadministration with antiarrhythmics.

            • deferasirox

              deferasirox will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • desvenlafaxine

              desvenlafaxine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg

            • diphenhydramine

              diphenhydramine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • dronedarone

              dronedarone will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • duloxetine

              duloxetine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • elranatamab

              elranatamab will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 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.

            • eltrombopag

              mexiletine will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • eluxadoline

              mexiletine increases levels of eluxadoline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP1A2 inhibitors.

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

            • epcoritamab

              epcoritamab, mexiletine. affecting hepatic enzyme CYP1A2 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. .

            • erythromycin base

              erythromycin base will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • erythromycin ethylsuccinate

              erythromycin ethylsuccinate will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • erythromycin lactobionate

              erythromycin lactobionate will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • erythromycin stearate

              erythromycin stearate will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • ethinylestradiol

              ethinylestradiol will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • ethotoin

              ethotoin decreases levels of mexiletine by increasing metabolism. Use Caution/Monitor.

            • fexinidazole

              fexinidazole will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • fosphenytoin

              fosphenytoin decreases levels of mexiletine by increasing metabolism. Use Caution/Monitor.

            • glofitamab

              glofitamab, mexiletine. affecting hepatic enzyme CYP1A2 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. .

            • green tea

              mexiletine increases levels of green tea by decreasing elimination. Use Caution/Monitor. (Caffeine). Combination may increase caffeine levels. Caution should be taken in patients with cardiac arrhythmias. Avoid or limit intake of caffeine.

            • haloperidol

              haloperidol will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised

              haloperidol and mexiletine both increase QTc interval. Use Caution/Monitor.

            • hawthorn

              hawthorn increases effects of mexiletine by pharmacodynamic synergism. Use Caution/Monitor.

            • imatinib

              imatinib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • imipramine

              mexiletine will increase the level or effect of imipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • isoniazid

              isoniazid will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • lidocaine

              mexiletine will increase the level or effect of lidocaine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • lonapegsomatropin

              lonapegsomatropin will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates

            • maraviroc

              maraviroc will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • marijuana

              marijuana will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • modafinil

              modafinil will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • nilotinib

              nilotinib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • olanzapine

              mexiletine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

              ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) will increase the level or effect of mexiletine by decreasing metabolism. Modify Therapy/Monitor Closely. Caution is warranted and therapeutic concentration monitoring (if available) is recommended for antiarrhythmics when coadministered with Viekira Pak

            • parecoxib

              parecoxib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • peginterferon alfa 2a

              peginterferon alfa 2a will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • peginterferon alfa 2b

              peginterferon alfa 2b, mexiletine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.

            • pentobarbital

              pentobarbital will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • pentoxifylline

              mexiletine will increase the level or effect of pentoxifylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • perphenazine

              perphenazine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • phenobarbital

              phenobarbital will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • phenytoin

              phenytoin decreases levels of mexiletine by increasing metabolism. Use Caution/Monitor.

            • pipemidic acid

              pipemidic acid will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • primidone

              primidone will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • propafenone

              propafenone will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • quinacrine

              quinacrine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • ramelteon

              mexiletine will increase the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • ranolazine

              ranolazine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • rasagiline

              mexiletine will increase the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Recommended dose of rasagiline is 0.5mg daily in combination with CYP1A2 inhibitors.

            • rifampin

              rifampin will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • ritlecitinib

              ritlecitinib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Ritlecitinib inhibits CYP1A2 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 CYP1A2 substrates.

            • ritonavir

              ritonavir will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Monitor patients for signs and symptoms of mexiletine toxicity (nausea, dizziness, cardiac arrhythmias). Therapeutic concentration monitoring is recommended for mexiletine, if available. Reduce doses of mexiletine as required.

            • ropinirole

              mexiletine will increase the level or effect of ropinirole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • rucaparib

              rucaparib will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP1A2 substrates, if clinically indicated.

            • secobarbital

              secobarbital will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • sevelamer

              sevelamer decreases levels of mexiletine by increasing elimination. Use Caution/Monitor.

            • smoking

              smoking will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • sodium bicarbonate

              sodium bicarbonate will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • sodium citrate/citric acid

              sodium citrate/citric acid will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • sodium lactate

              sodium lactate will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • somapacitan

              somapacitan will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 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 mexiletine by affecting hepatic enzyme CYP1A2 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 mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates

            • stiripentol

              stiripentol, mexiletine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP1A2 inhibitor and inducer. Monitor CYP1A2 substrates coadministered with stiripentol for increased or decreased effects. CYP1A2 substrates may require dosage adjustment.

            • talquetamab

              talquetamab will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 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.

            • tasimelteon

              mexiletine will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Avoid coadministration; potentially large increase in tasimelteon exposure and greater risk of adverse reactions with strong CYP1A2 inhibitors

            • terbinafine

              mexiletine will increase the level or effect of terbinafine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • teriflunomide

              teriflunomide decreases levels of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • theophylline

              mexiletine will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • thioridazine

              thioridazine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • tipranavir

              tipranavir will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • tobacco use

              tobacco use will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • venlafaxine

              venlafaxine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • verapamil

              verapamil will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • warfarin

              mexiletine will increase the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inhibitors of these isoenzymes and adjust warfarin dose if needed.

            • zileuton

              zileuton will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            Minor (9)

            • antipyrine

              mexiletine will increase the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • asenapine

              mexiletine will increase the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • caffeine

              mexiletine will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • frovatriptan

              mexiletine will increase the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • lily of the valley

              mexiletine, lily of the valley. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown.

            • omeprazole

              omeprazole will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • ondansetron

              mexiletine will increase the level or effect of ondansetron by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • riluzole

              mexiletine will increase the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • sertraline

              sertraline will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

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            Adverse Effects

            >10%

            Nausea (40%)

            Vomiting (40%)

            Heartburn (40%)

            Ataxia (20%)

            Dizziness (20-25%)

            Lightheadedness (11-25%)

            Tremor (13%)

            1-10%

            Coordination difficulties (10%)

            Palpitation (4-7%)

            Hypotension (4-8%)

            Angina (2%)

            Headache (5-7%)

            Depression (2%)

            Xerostomia (3%)

            Proarrhythmia (10-15%)

            Rash (4%)

            Insomnia (5-7%)

            Confusion (5-7%)

            Chest pain (3-8%)

            Abdominal pain (1%)

            Dyspnea (3%)

            Constipation or diarrhea (4-5%)

            Premature ventricular contractions (1-2%)

            Blurred vision (5-7%)

            Nystagmus (6%)

            Frequency Not Defined

            Edema

            Exacerbation of CHF

            Pulmonary fibrosis

            Proarrhythmia

            Convulsions

            Mouth sores

            Tinnitus

            Systemic lupus erythematosus

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            Warnings

            Black Box Warnings

            National Heart, Lung, and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST): Excessive mortality or nonfatal cardiac arrest (7.7%) shown with encainide or flecainide compared with placebo (3%)

            CAST was a long-term, multicenter, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction (MI) >6 days but <2 yr previously

            Average duration of treatment w/ encainide or flecainide in CAST was 10 months

            Applicability of CAST results to other populations (eg, patients without recent MI) is uncertain

            Reserve use of Class IC antiarrhythmics for life-threatening ventricular arrhythmias: Considering the known proarrhythmic properties of mexiletine & lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, mexiletine use, as well as other antiarrhythmic agents, should be reserved for patients with life-threatening ventricular arrhythmias

            Contraindications

            Hypersensitivity to mexiletine

            Cardiogenic shock, preexisting 2°/3° AV block without pacemaker

            Cautions

            Use caution in CHF, hypotension, history of seizures

            Monitor and adjust dose to prevent QTc prolongation

            Patients with second or third-degree heart block may be treated if continuously monitored; use caution when used in such patients or in patients with pre-existing sinus node dysfunction or intraventricular conduction abnormalities

            Use in less severe arrhythmias not recommended; avoid in treatment of asymptomatic ventricular premature contractions or conduction disturbances

            Some abnormal liver function tests reported in first few weeks of therapy; most have been observed in setting of congestive heart failure or ischemia; patients with liver disease should be followed carefully while receiving therapy; caution should also be observed in patients with hepatic dysfunction secondary to congestive heart failure

            Rare instances of severe liver injury, including hepatic necrosis, reported in association with treatment; recommended that patients in whom an abnormal liver test has occurred, or who have signs or symptoms suggesting liver dysfunction, be carefully evaluated; if persistent or worsening elevation of hepatic enzymes is detected, consider discontinuing therapy

            Prior to use electrolyte imbalances (especially hypokalemia or hypomagnesemia) must be corrected

            Avoid concurrent drug therapy or dietary regimens which may markedly alter urinary pH during therapy; the minor fluctuations in urinary pH associated with normal diet do not affect excretion of drug

            Marked leukopenia, agranulocytosis and mild depressions of leukocytes and thrombocytopenia reported (rare); If significant hematologic changes observed, patient should be carefully evaluated, and, if warranted, therapy should be discontinued; blood counts usually return to normal within one month of discontinuation

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            Pregnancy & Lactation

            Pregnancy Category: C

            Lactation: enters breast milk at concs comparable to maternal plasma (AAP Committee states compatible w/ 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.

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            Pharmacology

            Mechanism of Action

            Class 1B antidysrhythmic; combines with fast Na channels & thereby inhibits recovery after repolarization resulting in decreasing myocardial excitability & conduction velocity

            Pharmacokinetics

            Bioavailability: 80-90%

            Protein Bound: 50-60%

            Half-Life: 10-14 hr (adults)

            Peak Plasma Time: 2-3 hr (PO)

            Therapeutic range: 0.5-2 mcg/mL

            Toxicity range: >2 mcg/mL

            Vd: 5-7 L/kg

            Metabolism: in liver to form parahydroxymexiletine & 2-hydroxymexiletine mainly by hepatic P450 enzyme CYP2D6 & partially by CYP1A2

            Metabolites: parahydroxymexiletine & 2-hydroxymexiletine (inactive)

            Excretion: urine 10-15%

            Dialyzable: HD: No; PD: No

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            mexiletine oral
            -
            150 mg capsule
            mexiletine oral
            -
            250 mg capsule
            mexiletine oral
            -
            200 mg capsule
            mexiletine oral
            -
            250 mg capsule
            mexiletine oral
            -
            200 mg capsule
            mexiletine oral
            -
            150 mg capsule
            mexiletine oral
            -
            250 mg capsule
            mexiletine oral
            -
            200 mg capsule
            mexiletine oral
            -
            150 mg capsule
            mexiletine oral
            -
            250 mg capsule
            mexiletine oral
            -
            200 mg capsule
            mexiletine oral
            -
            150 mg capsule
            mexiletine oral
            -
            200 mg capsule
            mexiletine oral
            -
            150 mg capsule

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

            Patient Education
            mexiletine oral

            MEXILETINE - ORAL

            (mex-IL-e-teen)

            COMMON BRAND NAME(S): Mexitil

            WARNING: Though this medication often gives great benefits to people with irregular heartbeat, it may rarely cause a serious new irregular heartbeat. When starting treatment with this drug, your doctor may recommend that you stay in the hospital for proper monitoring. Talk with your doctor about the benefits and risks of taking this medication for your condition.

            USES: This medication is used to treat certain types of serious (possibly fatal) irregular heartbeat (such as sustained ventricular tachycardia). It is used to restore normal heart rhythm and maintain a regular, steady heartbeat. Mexiletine is known as an anti-arrhythmic drug. It works by blocking certain electrical signals in the heart that can cause an irregular heartbeat. Treating an irregular heartbeat can decrease the risk for blood clots, and this effect can reduce your risk of heart attack or stroke.

            HOW TO USE: Take this medication by mouth with a full glass of water (8 ounces/240 milliliters and food or an antacid, usually 2 to 3 times daily or exactly as directed by your doctor. Taking this medication with food or an antacid helps to decrease certain side effects (nausea, heartburn). Ask your pharmacist if you have questions about which antacids to use with this medication.Dosage is based on your age, liver function, medical condition, and response to treatment.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.Tell your doctor if your condition does not improve or if it worsens.

            SIDE EFFECTS: See also Warning section.Nausea, vomiting, heartburn, dizziness, lightheadedness, vision problems (such as blurred vision), headache, shaking, nervousness, or problems with muscle control (coordination difficulties) 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: worsening symptoms of heart failure (such as shortness of breath, swelling ankles/feet, unusual tiredness, unusual/sudden weight gain), signs of liver problems (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine).Get medical help right away if you have any very serious side effects, including: chest pain, seizure.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: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.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 mexiletine, tell your doctor or pharmacist if you are allergic to it; 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: other heart problems (such as heart failure, slow heartbeat, previous heart attack), liver problems, seizure disorder.This drug may make you dizzy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).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. However, this drug is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: 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 are: caffeine, fezolinetant, theophylline, drugs that may affect the acid level of urine (such as sodium bicarbonate, large doses of vitamin C).Other medications can affect the removal of mexiletine from your body, which may affect how mexiletine works. Examples include cimetidine, fluvoxamine, propafenone, anti-seizure drugs (such as phenytoin, phenobarbital), among others.

            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: drowsiness, confusion, fainting, seizures.

            NOTES: Do not share this medication with others.Lab and/or medical tests (such as EKG, blood pressure) 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 May 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.

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            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.