Sildenafil 4- Tricyclic antidepressants

Drugs that might be affected by amprenavir include antiarrhythmics, anticonvulsants, azole antifungals, benzodiazepines, calcium channel blockers, cisapride, clarithromycin, cyclosporine, ergot alkaloids, fentanyl, HMG-CoA reductase inhibitors, indinavir, methadone, nelfinavir, oral contraceptives, pimozide, rifabutin, ritonavir, saquinavir, sildenafil, tacrolimus, trazodone, tricyclic antidepressants, warfarin, and zidovudine. 

Clinically important, potentially hazardous interactions with amiodarone, amitriptyline, amoxapine, benzodiazepines, bepridil, clomipramine, clonazepam, clorazepate, delavirdine, desipramine, diazepam, dihydroergotamine, doxepin, ergotamine, fentanyl, flurazepam, imipramine, ixabepilone, lidocaine, lorazepam, methysergide, midazolam, nortriptyline, oxazepam, phenytoin, protriptyline, quazepam, quinidine, rifampin, ritonavir, sildenafil, St John s wort, temazepam, tricyclic antidepressants, trimipramine, vitamin E... 

Retrospective analysis of clinical study data su ested that SSRIs and tricyclic antidepressants did not alter sildenafil pharmacokinetics. However, in one study fluvoxamine was found to modestly increase the levels and vascular effects of sildenafil. 

The manufacturer notes that population pharmacokinetie analysis of elin-ical study data indieate that inhibitors of cytochrome P450 isoenzyme CYP2D6 such as SSRIs and tricyclic antidepressants do not have any effect on the pharmacokinetics of sildenafil. However, in a double-blind, placebo-controlled study in healthy subjects, pre-treatment with fluvox-amine 50 mg daily for 3 days then 100 mg daily for 6 days increased the AUC of sildenafil 50 mg by 40%. This resulted in an inerease in the vascular effects of sildenafil. ... 

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