Probenecid Famciclovir

The conversion of 6-deoxy penciclovir to penciclovir is catalyzed by aldehyde oxidase. Interactions with other drugs metabolized by this enzyme could occur. Concurrent use with probenecid or other drugs significantly eliminated by active renal tubular secretion may result in increased plasma concentrations of penciclovir. Drug/Food interactions When famciclovir was administered with food, penciclovir Cmax decreased approximately 50%. Because the systemic availability of penciclovir (AUC) was not altered, it appears that famciclovir may be taken without regard to meals. 

Famciclovir (Famvir) [Antiviral/Synthetic Nucleoside] Uses Acute h pes zoster (shingles) genital h pes Action X Viral DNA synth Dose Zoster 500 mg PO q8h x7 d Simplex 125-250 mg PO bid X w/ renal impair Caution [B, -] Contra Component sensitivity Disp Tabs SE Fatigue, dizziness, HA, pruritus, N/D Interactions t Effects cimetidine, probenecid, theophylline t effects OF digoxin EMS None OD Sxs unknown, but may cause hallucinations, Szs and reduced kidney Fxn... 

Famciclovir may interact with probenecid or other drugs eliminated by renal tubular secretion. This interaction may result in increased blood levels of penciclovir or other agents. 

Famciclovir can be given with or without food. The most common adverse effects are headache and Gl disturbances. Concomitant use of famciclovir with probenecid results in increased plasma concentratiens of penciclovir. The recommended dose of famciclovir is 500 mg every 8 hours for 7 days. The absolute bioavailability of famciclovir is 77%, and the area under plasma concentration-time curve (AUC) is 86 pg/mL. Famcicicvir with digexin increased plasma ccncentraticn cf digexin tc 19% as compared to digoxin given alone. 

Probenecid reduces the renal excretion and increases the plasma levels of aciclovir, valaciclovir, and ganciclovir. Famciclovir and valganciclovir are predicted to interact similarly. 

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