trimethoprim (Rx)

Brand and Other Names:Primsol, Proloprim, more...TMP

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

oral solution

  • 50mg/5mL

tablet

  • 100mg

Susceptible Infections

100 mg PO q12hr

Dosing Modifications

Renal impairment

  • CrCl 15-30 mL/min: 50 mg q12hr
  • CrCl <15 mL/min: 100 mg q24hr or avoid use

Other Information

See also combo with sulfamethoxazole (Cotrim/Bactrim/Septra/Sulfatrim)

Other Indications and Uses

UTI caused by E. coli, Enterobacter spp., K. pneumoniae, P. mirabilis, coagulase-neg Staphylococcus spp.

<12 years old: safety and efficacy not established

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Interactions

Interaction Checker

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              • abametapir

                abametapir will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

              • amiodarone

                amiodarone and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • apalutamide

                apalutamide will decrease the level or effect of trimethoprim 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.

              • BCG vaccine live

                trimethoprim decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

              • cholera vaccine

                trimethoprim, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.

              • disopyramide

                disopyramide and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • erdafitinib

                trimethoprim will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

              • fexinidazole

                fexinidazole will increase the level or effect of trimethoprim 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.

              • ibutilide

                ibutilide and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • idelalisib

                idelalisib will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

              • indapamide

                indapamide and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • ivosidenib

                ivosidenib will decrease the level or effect of trimethoprim 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.

                ivosidenib will decrease the level or effect of trimethoprim by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2C9 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

              • leucovorin

                leucovorin decreases effects of trimethoprim by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Monitor for trimethoprim treatment failure or decreased efficacy when coadministered with leucovorin, especially when used with sulfamethoxazole for Pneumocystis jiroveci pneumonia in patients who are HIV positive .

              • levoleucovorin

                levoleucovorin decreases effects of trimethoprim by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Monitor for trimethoprim treatment failure or decreased efficacy when coadministered with levoleucovorin, especially when used with sulfamethoxazole for Pneumocystis jiroveci pneumonia in patients who are HIV positive .

              • lonafarnib

                lonafarnib will increase the level or effect of trimethoprim 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.

              • lopinavir

                lopinavir will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

              • mefloquine

                mefloquine increases toxicity of trimethoprim by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.

              • methotrexate

                trimethoprim, methotrexate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Due to an additive antifolate effect, trimethoprim has been shown to rarely increase bone marrow suppression in patients receiving methotrexate.

              • microbiota oral

                trimethoprim decreases effects of microbiota oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Microbiota oral contains bacterial spores. Antibacterial agents may decrease efficacy if coadministered. Complete antibiotic regimens 2-4 days before initiating microbiota oral. .

              • pentamidine

                pentamidine and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • pimozide

                pimozide and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • procainamide

                procainamide and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • quinidine

                quinidine and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • siponimod

                trimethoprim will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.

              • sotalol

                sotalol and trimethoprim both increase QTc interval. Avoid or Use Alternate Drug.

              • tafenoquine

                tafenoquine will increase the level or effect of trimethoprim by Other (see comment). Avoid or Use Alternate Drug. Tafenoquine inhibits organic cation transporter-2 (OCT2) and multidrug and toxin extrusion (MATE) transporters in vitro. Avoid coadministration with OCT2 or MATE substrates. If coadministration cannot be avoided, monitor for substrate-related toxicities and consider dosage reduction if needed based on product labeling of the coadministered drug.

              • trilaciclib

                trilaciclib will decrease the level or effect of trimethoprim by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of trilaciclib (OCT2, MATE1, and MATE-2K inhibitor) with substrates where minimal increased concentration in kidney or blood may lead to serious or life-threatening toxicities.

              • tucatinib

                trimethoprim will increase the level or effect of tucatinib by Other (see comment). Avoid or Use Alternate Drug. Coadministration of tucatinib (a CYP2C8 substrate) with a strong or moderate CYP2C8 inhibitors increases tucatinib plasma concentrations and risk of toxicities.

                tucatinib will increase the level or effect of trimethoprim 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.

              • typhoid vaccine live

                trimethoprim decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

              • voxelotor

                voxelotor will increase the level or effect of trimethoprim 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 (140)

              • aliskiren

                trimethoprim and aliskiren both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • alpelisib

                alpelisib will decrease the level or effect of trimethoprim by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

              • amantadine

                trimethoprim increases levels of amantadine by decreasing elimination. Use Caution/Monitor. Coadministration may impair renal clearance of amantadine, resulting in higher plasma concentrations.

              • amiloride

                trimethoprim and amiloride both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • amiodarone

                amiodarone will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • amitriptyline

                amitriptyline and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • amoxapine

                amoxapine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • apalutamide

                apalutamide will decrease the level or effect of trimethoprim by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Coadministration of apalutamide, a weak CYP2C9 inducer, with drugs that are CYP2C9 substrates can result in lower exposure to these medications. Evaluate for loss of therapeutic effect if medication must be coadministered.

              • artemether/lumefantrine

                artemether/lumefantrine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • bazedoxifene/conjugated estrogens

                trimethoprim will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • benazepril

                trimethoprim and benazepril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • canagliflozin

                trimethoprim and canagliflozin both increase serum potassium. Use Caution/Monitor.

              • candesartan

                trimethoprim and candesartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • cannabidiol

                cannabidiol will increase the level or effect of trimethoprim by decreasing metabolism. Modify Therapy/Monitor Closely. Cannabidiol may potentially inhibit CYP2C9 activity. Consider reducing the dose when concomitantly using CYP2C9 substrates.

              • captopril

                trimethoprim and captopril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • chlorpromazine

                chlorpromazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • cimetidine

                cimetidine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • clarithromycin

                clarithromycin and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • clomipramine

                clomipramine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • conjugated estrogens

                trimethoprim will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • crofelemer

                crofelemer increases levels of trimethoprim 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

                trimethoprim and cyclosporine both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • dabrafenib

                dabrafenib will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

              • dapsone topical

                trimethoprim increases toxicity of dapsone topical by decreasing metabolism. Modify Therapy/Monitor Closely. Coadministration increases systemic exposure of dapsone and its metabolites (N-acetyl-dapsone, dapsone hydroxylamine). May induce methemoglobinemia.

              • desipramine

                desipramine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • digoxin

                trimethoprim will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.

                digoxin will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • dofetilide

                dofetilide will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

                dofetilide and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • dolasetron

                dolasetron and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • doxepin

                doxepin and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • dronedarone

                dronedarone and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • droperidol

                droperidol and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • elagolix

                elagolix decreases levels of trimethoprim 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.

              • elvitegravir/cobicistat/emtricitabine/tenofovir DF

                elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of trimethoprim 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.

                elvitegravir/cobicistat/emtricitabine/tenofovir DF decreases levels of trimethoprim by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Elvitegravir is a moderate CYP2C9 inducer.

              • enalapril

                trimethoprim and enalapril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • encorafenib

                encorafenib, trimethoprim. 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.

              • epinephrine

                epinephrine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • epinephrine racemic

                epinephrine racemic and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • eplerenone

                trimethoprim and eplerenone both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • eprosartan

                trimethoprim and eprosartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • erdafitinib

                erdafitinib increases levels of trimethoprim by decreasing renal clearance. Modify Therapy/Monitor Closely. Consider alternatives that are not OCT2 substrates or consider reducing the dose of OCT2 substrates based on tolerability.

              • erythromycin base

                erythromycin base and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin ethylsuccinate

                erythromycin ethylsuccinate and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin lactobionate

                erythromycin lactobionate and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin stearate

                erythromycin stearate and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • estradiol

                trimethoprim will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • estrogens conjugated synthetic

                trimethoprim will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • estropipate

                trimethoprim will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • ethinylestradiol

                trimethoprim will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • fedratinib

                fedratinib will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

              • finerenone

                trimethoprim and finerenone both increase serum potassium. Modify Therapy/Monitor Closely. Finerenone dose adjustment based on current serum potassium concentration. Monitor serum potassium and adjust finerenone dose as described in the prescribing information as necessary.

              • flecainide

                flecainide and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • fluconazole

                fluconazole and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • fluoxetine

                fluoxetine and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • fluphenazine

                fluphenazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • fluvoxamine

                fluvoxamine and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • formoterol

                formoterol and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • foscarnet

                foscarnet and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • fosinopril

                trimethoprim and fosinopril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • fosphenytoin

                fosphenytoin will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • glucarpidase

                glucarpidase will decrease the level or effect of trimethoprim by increasing metabolism. Modify Therapy/Monitor Closely. Leucorvorin, reduced folates, and folate antimetabolites are substrates for glucarpidase (hydrolyzes glutamate residue from folic acid and antifolates)

              • haloperidol

                haloperidol and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • iloperidone

                iloperidone and trimethoprim both increase QTc interval. Use Caution/Monitor.

                iloperidone increases levels of trimethoprim 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.

              • imipramine

                imipramine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • indinavir

                indinavir will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • irbesartan

                trimethoprim and irbesartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • istradefylline

                istradefylline will increase the level or effect of trimethoprim 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.

              • itraconazole

                itraconazole and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • ketoconazole

                ketoconazole and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • L-methylfolate

                trimethoprim decreases effects of L-methylfolate by Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Folic acid antagonists may interfere with folic acid utilization.

              • lamivudine

                trimethoprim increases effects of lamivudine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor. Potential for increased toxicity.

              • lenacapavir

                lenacapavir will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.

              • levofloxacin

                levofloxacin and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • levoketoconazole

                levoketoconazole and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

                trimethoprim will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.

              • lisinopril

                trimethoprim and lisinopril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • lofepramine

                lofepramine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • losartan

                trimethoprim and losartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • lumacaftor/ivacaftor

                lumacaftor/ivacaftor, trimethoprim. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C9 substrates. .

              • lumefantrine

                lumefantrine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • maprotiline

                maprotiline and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • mestranol

                trimethoprim will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • metformin

                trimethoprim increases levels of metformin by Other (see comment). Use Caution/Monitor. Comment: Trimethoprim may inhibit active renal tubular secretion of metformin (eg, via OCT2, MATE1); dose adjustments may be necessary.

              • methadone

                methadone and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • methotrexate

                trimethoprim increases toxicity of methotrexate by Other (see comment). Use Caution/Monitor. Comment: Trimethoprim may increase risk of methotrexate-induced bone marrow suppression and megaloblastic anemia. If this drug combination cannot be avoided, closely monitor for signs of hematologic toxicity.

              • mitotane

                mitotane decreases levels of trimethoprim 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.

              • moexipril

                trimethoprim and moexipril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • moxifloxacin

                moxifloxacin and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • nitisinone

                nitisinone will increase the level or effect of trimethoprim by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Nitisinone inhibits CYP2C9. Caution if CYP2C9 substrate coadministered, particularly those with a narrow therapeutic index.

              • nortriptyline

                nortriptyline and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • octreotide

                octreotide and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • octreotide (Antidote)

                octreotide (Antidote) and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • ofloxacin

                ofloxacin and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • olmesartan

                trimethoprim and olmesartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • paclitaxel

                trimethoprim will increase the level or effect of paclitaxel by Other (see comment). Use Caution/Monitor. Paclitaxel levels/toxicity may increase when coadministered with CYP2C8 inhibitors

              • paclitaxel protein bound

                trimethoprim will increase the level or effect of paclitaxel protein bound by Other (see comment). Use Caution/Monitor. Paclitaxel levels/toxicity may increase when coadministered with CYP2C8 inhibitors

              • paliperidone

                paliperidone and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • paroxetine

                paroxetine and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • pentamidine

                trimethoprim and pentamidine both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • perindopril

                trimethoprim and perindopril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • perphenazine

                perphenazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • posaconazole

                posaconazole and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • potassium acid phosphate

                trimethoprim and potassium acid phosphate both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • potassium chloride

                trimethoprim and potassium chloride both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • potassium citrate

                trimethoprim and potassium citrate both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • potassium citrate/citric acid

                trimethoprim and potassium citrate/citric acid both increase serum potassium. Use Caution/Monitor.

              • procainamide

                procainamide will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • prochlorperazine

                prochlorperazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • promazine

                promazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • promethazine

                promethazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • protriptyline

                protriptyline and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • quinapril

                trimethoprim and quinapril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • quinidine

                quinidine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • ramipril

                trimethoprim and ramipril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • ranolazine

                ranolazine and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • repaglinide

                trimethoprim increases levels of repaglinide by decreasing metabolism. Use Caution/Monitor. Hepatic cytochrome P450 2C8.

              • rifabutin

                rifabutin will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • rifampin

                rifampin will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • risperidone

                risperidone and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • sacubitril/valsartan

                sacubitril/valsartan and trimethoprim both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • selexipag

                trimethoprim will increase the level or effect of selexipag by decreasing metabolism. Modify Therapy/Monitor Closely. Reduce selexipag dose to once daily if coadministered with moderate CYP2C8 inhibitors.

              • sodium picosulfate/magnesium oxide/anhydrous citric acid

                trimethoprim decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

              • sparsentan

                sparsentan will decrease the level or effect of trimethoprim by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C9 inducer) decreases exposure of CYP2C9 substrates and reduces efficacy related to these substrates.

              • spironolactone

                trimethoprim and spironolactone both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • sulfamethoxazole

                sulfamethoxazole and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • tecovirimat

                tecovirimat will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

              • telavancin

                telavancin and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • telmisartan

                trimethoprim and telmisartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • thioridazine

                thioridazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • trandolapril

                trimethoprim and trandolapril both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • trazodone

                trazodone and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • triamterene

                trimethoprim and triamterene both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • trifluoperazine

                trifluoperazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • trimipramine

                trimipramine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

              • tropisetron

                trimethoprim and tropisetron both increase QTc interval. Use Caution/Monitor.

              • valsartan

                valsartan and trimethoprim both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

              • venlafaxine

                trimethoprim and venlafaxine both increase QTc interval. Use Caution/Monitor.

              • voclosporin

                voclosporin and trimethoprim both decrease serum potassium. Use Caution/Monitor.

              • voriconazole

                trimethoprim and voriconazole both increase QTc interval. Use Caution/Monitor.

              • zidovudine

                trimethoprim increases levels of zidovudine by decreasing renal clearance. Use Caution/Monitor. Potential for increased toxicity. .

              • ziprasidone

                trimethoprim and ziprasidone both increase QTc interval. Modify Therapy/Monitor Closely.

              Minor (35)

              • acetazolamide

                acetazolamide will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

              • amiloride

                amiloride, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Hyperkalemia.

              • anastrozole

                anastrozole will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

              • azithromycin

                azithromycin and trimethoprim both increase QTc interval. Minor/Significance Unknown.

              • balsalazide

                trimethoprim will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

              • bendroflumethiazide

                bendroflumethiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • biotin

                trimethoprim will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

              • chlorothiazide

                chlorothiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • chlorthalidone

                chlorthalidone, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • cyclopenthiazide

                cyclopenthiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • cyclophosphamide

                cyclophosphamide will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

              • dapsone

                trimethoprim, dapsone. Either increases levels of the other by decreasing elimination. Minor/Significance Unknown.

              • drospirenone

                drospirenone, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Hyperkalemia.

              • hydrochlorothiazide

                hydrochlorothiazide will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

                hydrochlorothiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • indapamide

                indapamide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • isavuconazonium sulfate

                isavuconazonium sulfate will increase the level or effect of trimethoprim by Other (see comment). Minor/Significance Unknown. Isavuconazonium sulfate, an OCT2 inhibitor, may increase the effects or levels of OCT2 substrates.

              • larotrectinib

                larotrectinib will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

              • levoketoconazole

                levoketoconazole will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

              • memantine

                memantine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • metformin

                metformin will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • methyclothiazide

                methyclothiazide will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

                methyclothiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • metolazone

                metolazone, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

              • midodrine

                midodrine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • ofloxacin

                ofloxacin will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • pantothenic acid

                trimethoprim will decrease the level or effect of pantothenic acid by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

              • patiromer

                patiromer, trimethoprim. cation binding in GI tract. Minor/Significance Unknown. No observed clinically important interaction. No separation of dosing required.

              • pyridoxine

                trimethoprim will decrease the level or effect of pyridoxine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

              • pyridoxine (Antidote)

                trimethoprim will decrease the level or effect of pyridoxine (Antidote) by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

              • quinine

                quinine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • ribociclib

                ribociclib will increase the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

              • spironolactone

                spironolactone, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Hyperkalemia.

              • sulfamethoxazole

                sulfamethoxazole will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • thiamine

                trimethoprim will decrease the level or effect of thiamine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

              • triamterene

                triamterene will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

                triamterene, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Hyperkalemia.

              • verapamil

                trimethoprim will increase the level or effect of verapamil by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

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              Adverse Effects

              Frequency Not Defined

              Aseptic meningitis

              Fever

              Maculopapular rash (3-7% at 200 mg/day; incidence higher with larger daily doses)

              Erythema multiforme

              Exfoliative dermatitis

              Pruritus (common)

              Phototoxic skin eruptions

              Stevens-Johnson syndrome

              Toxic epidermal necrolysis

              Hyperkalemia

              Hyponatremia

              Epigastric distress

              Glossitis

              Nausea

              Vomiting

              Leukopenia

              Megaloblastic anemia

              Methemoglobinemia

              Neutropenia

              Thrombocytopenia

              Liver enzyme elevation

              Cholestatic jaundice

              BUN and creatinine increased

              Anaphylaxis

              Hypersensitivity reactions

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              Warnings

              Contraindications

              Hypersensitivity

              Megaloblastic anemia due to folate deficiency

              Cautions

              Decreases urinary potassium excretion; may cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia

              Large doses or long term therapy may interfere with hematopoiesis; the presence of clinical signs, such as sore throat, fever, pallor, or purpura may be early indications of serious blood disorders; monitor for signs/symptoms of hematologic disorders

              If clinical signs of blood disorder noted, obtain a complete blood count and discontinue drug if significant reduction in count of any blood element found

              Prolonged use may cause fungal or bacterial superinfection, including clostridium difficile-associated diarrhea and pseudomembranous colitis; may occur >2 months postantibiotic treatment

              Hypersensitivity reactions reported

              Use caution in patients with renal or hepatic impairment

              Use caution in patients with potential for folate deficiency, including malnourished, chronic anticonvulsant therapy, or elderly; folates may be administered concomitantly without interfering with antibacterial action of trimethoprim

              Some dosage forms may contain benzyl alcohol and derivatives; avoid in neonates

              Not indicated for prophylactic or prolonged administration in otitis media at any age

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              Pregnancy & Lactation

              Pregnancy Category: C

              Lactation: enters breast milk

              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

              Inhibits dihydrofolate reductase, which in turn inhibits folic acid reduction to tetrahydrofolate, causing inhibition of microorganism growth

              Absorption

              Readily and extensive

              Time to peak, serum: 1-4 hr

              Distribution

              Widely into body tissues and fluids (middle ear, prostate, bile, aqueous humor, CSF); crosses placenta; enters breast milk

              Protein binding: 42-46%

              Metabolism

              Partially hepatic

              Elimination

              Half-life: 8-14 hr; prolonged in renal impairment

              Excretion: urine (60-80%) as unchanged drug

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              trimethoprim oral
              -
              100 mg tablet
              trimethoprim oral
              -
              100 mg tablet
              trimethoprim oral
              -
              100 mg tablet

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              trimethoprim oral

              TRIMETHOPRIM - ORAL

              (try-METH-oh-prim)

              COMMON BRAND NAME(S): Primsol, Proloprim, Trimpex

              USES: Trimethoprim is an antibiotic used to treat bacterial infections. It works by stopping the growth of bacteria.This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Using any antibiotic when it is not needed can cause it to not work for future infections.

              HOW TO USE: Take this medication by mouth with or without food as directed by your doctor, usually once or twice daily. The dosage is based on your medical condition and response to treatment. In children, the dosage is also based on their weight.If you are using the liquid form of this medication, carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.Tell your doctor if your condition lasts or gets worse after several days.

              SIDE EFFECTS: Diarrhea, nausea, vomiting, stomach upset, loss of appetite, changes in taste, and headache 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: new signs of infection (such as sore throat that doesn't go away, fever), easy bruising/bleeding, pale skin, unusual tiredness, fast/irregular heartbeat, mental/mood changes, signs of liver disease (such as nausea/vomiting that doesn't stop, dark urine, stomach/abdominal pain, yellowing eyes/skin), stiff neck, headache that doesn't go away, muscle weakness, extreme drowsiness, signs of low blood sugar (such as sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, or tingling hands/feet).This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool.If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.Get medical help right away if you have any very serious side effects, including: seizures.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.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 trimethoprim, 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: a certain type of anemia (due to folate deficiency), kidney disease, liver disease, vitamin deficiency (folate or folic acid), blood disorders (such as bone marrow suppression, G6PD deficiency), mineral imbalances (such as high level of potassium or low level of sodium in the blood).This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.If you have diabetes, this product may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of low blood sugar (see Side Effects section). Your doctor may need to adjust your diabetes medication, exercise program, or diet.Trimethoprim may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using trimethoprim before having any immunizations/vaccinations.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Older adults may be more sensitive to the side effects of this drug, especially mineral imbalance (high potassium blood level) and allergic reactions.Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using trimethoprim. Trimethoprim may harm an unborn baby. It may lower your folic acid levels, increasing the risk of spinal cord defects. Check with your doctor to make sure you are taking enough folic acid. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.Trimethoprim passes into breast milk. While there have been no reports of harm to nursing infants, 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.A product that may interact with this drug is: dofetilide.This medication may interfere with certain lab tests (including kidney function and methotrexate blood levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

              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: mental/mood changes (such as confusion), easy bruising/bleeding.

              NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.Lab and/or medical tests (such as complete blood counts, kidney function, potassium blood level, cultures) should be done while you are using 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.

              Information last revised October 2021. 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.
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              • 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.