Famciclovir interactions

Famciclovir (Famvir), an antiviral has 39 documented interactions across the FDA labels and fact sheets we index: 0 major, 2 moderate, 28 minor, and 9 where a label reports no significant interaction. Each entry below quotes the sentence behind it. This drug page is a starting point, not a verdict for your situation.

Moderate interactions (2)

  • Digoxindigitalis glycosideModerate

    Potential for Famciclovir to Affect Other Drugs The steady-state pharmacokinetics of digoxin were not altered by concomitant administration of multiple doses of famciclovir (500 mg three times daily). (Famciclovir label, Drug interactions)

  • Raloxifeneselective estrogen receptor modulatorModerate

    Raloxifene, a potent aldehyde oxidase inhibitor in vitro , could decrease the formation of penciclovir. (Famciclovir label, Drug interactions)

Minor mentions (28)

  • AmiodaroneantiarrhythmicMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • AprepitantCYP3A4 inhibitorMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • CenobamateanticonvulsantMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • CimetidineH2 blockerMinor

    Clinical interaction studies of famciclovir with cimetidine and promethazine, in vitro inhibitors of aldehyde oxidase, did not show relevant effects on the formation of penciclovir. (Famciclovir label, Drug interactions)

  • Clarithromycinmacrolide antibioticMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • CyclosporineimmunosuppressantMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Diltiazemcalcium channel blockerMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • DronedaroneantiarrhythmicMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Erythromycinmacrolide antibioticMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • EverolimusimmunosuppressantMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Fluconazoleazole antifungalMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • ImatinibCYP3A4 inhibitorMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • IsoniazidantibioticMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Itraconazoleazole antifungalMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • IvacaftorCYP3A4 inhibitorMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Ketoconazoleazole antifungalMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Mirabegronbeta-adrenergic agonistMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Nirmatrelvir and ritonavirantiviralMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • PalbociclibCYP3A4 inhibitorMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • PerampanelanticonvulsantMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Posaconazoleazole antifungalMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • PromethazineantihistamineMinor

    Clinical interaction studies of famciclovir with cimetidine and promethazine, in vitro inhibitors of aldehyde oxidase, did not show relevant effects on the formation of penciclovir. (Famciclovir label, Drug interactions)

  • RanolazineQT-prolonging drugMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • RitonavirantiretroviralMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Suvorexantsedative-hypnoticMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Ticagrelorantiplatelet agentMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Verapamilcalcium channel blockerMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

  • Voriconazoleazole antifungalMinor

    An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. (Famciclovir label, Drug interactions)

No significant interaction reported (9)

  • Allopurinolxanthine oxidase inhibitorNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • Antacids (Tums, Maalox, Mylanta)OTC productNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • Bictegravir, emtricitabine, and tenofovir alafenamideantiretroviralNo interaction

    No clinically significant effect on the pharmacokinetics of zidovudine, its metabolite zidovudine glucuronide, or emtricitabine was observed following a single oral dose of 500 mg famciclovir coadministered with zidovudine or emtricitabine. (Famciclovir label, Drug interactions)

  • Butalbital, acetaminophen, and caffeinebarbiturateNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • Emtricitabine and tenofovirantiretroviralNo interaction

    No clinically significant effect on the pharmacokinetics of zidovudine, its metabolite zidovudine glucuronide, or emtricitabine was observed following a single oral dose of 500 mg famciclovir coadministered with zidovudine or emtricitabine. (Famciclovir label, Drug interactions)

  • Febuxostatxanthine oxidase inhibitorNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • PentoxifyllinemethylxanthineNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • Sodium bicarbonateantacidNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

  • TheophyllinemethylxanthineNo interaction

    …Penciclovir No clinically significant alterations in penciclovir pharmacokinetics were observed following single-dose administration of 500 mg famciclovir after pretreatment with multiple doses of allopurinol, cimetidine, theophylline, zidovudine, promethazine, when given shortly after an antacid (magnesium and aluminum hydroxide), or concomitantly with emtricitabine. (Famciclovir label, Drug interactions)

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Not medical advice. Severity reflects the label's wording, not your circumstances. A "major" flag can be routine under supervision and a "minor" one can matter at high doses. Ask a pharmacist.