Overview
DESCRIPTION Acyclovir is a synthetic nucleoside analogue active against herpesviruses. Acyclovir capsules are formulations for oral administration. Each capsule contains 200 mg of acyclovir and the inactive ingredients: lactose monohydrate, sodium lauryl sulfate, corn starch, and magnesium stearate. The capsule shell consists of FD&C Blue #1, gelatin, and titanium dioxide.
Mechanism of Action
CLINICAL PHARMACOLOGY Pharmacokinetics: The pharmacokinetics of acyclovir after oral administration have been evaluated in healthy volunteers and in immunocompromised patients with herpes simplex or varicella-zoster virus infection. Acyclovir pharmacokinetic parameters are summarized in Table 1 . In one multiple-dose, crossover study in healthy subjects (n = 23), it was shown that increases in plasma Acyclovir concentrations were less than dose proportional with increasing dose, as shown in Table 2 . The decrease in bioavailability is a function of the dose and not the dosage form. There was no effect of food on the absorption of acyclovir (n = 6); therefore, acyclovir capsules may be administered with or without food. The only known urinary metabolite is 9-[(carboxymethoxy)methyl]guanine.
Indications
- INDICATIONS AND USAGE Herpes Zoster Infections : Acyclovir is indicated for the acute treatment of herpes zoster (shingles). Genital Herpes : Acyclovir is indicated for the treatment of initial episodes and the management of recurrent episodes of genital herpes. Chickenpox : Acyclovir is indicated for the treatment of chickenpox (varicella).
Common Doses
- 800 mg
- 200 mg
- 400 mg
- 20 mg
Dosage
DOSAGE AND ADMINISTRATION Acute Treatment of Herpes Zoster : 800 mg every 4 hours orally, 5 times daily for 7 to 10 days. Genital Herpes : Treatment of Initial Genital Herpes: 200 mg every 4 hours, 5 times daily for 10 days. Chronic Suppressive Therapy for Recurrent Disease: 400 mg 2 times daily for up to 12 months, followed by re-evaluation. Alternative regimens have included doses ranging from 200 mg 3 times daily to 200 mg 5 times daily. The frequency and severity of episodes of untreated genital herpes may change over time.
Contraindications
- CONTRAINDICATIONS Acyclovir is contraindicated for patients who develop hypersensitivity to acyclovir or valacyclovir.
Side Effects
- ADVERSE REACTIONS Herpes Simplex: Short-Term Administration: The most frequent adverse events reported during clinical trials of treatment of genital herpes with acyclovir 200 mg administered orally 5 times daily every 4 hours for 10 days were nausea and/or vomiting in 8 of 298 patient treatments (2.7%). Nausea and/or vomiting occurred in 2 of 287 (0.7%) patients who received placebo. Long-Term Administration: The most frequent adverse events reported in a clinical trial for the prevention of recurrences with continuous administration of 400 mg (two 200-mg capsules) 2 times daily for 1 year...
Interactions
- Drug Interactions: See CLINICAL PHARMACOLOGY: Pharmacokinetics .