Data from more than 35 million patients have been consistent and reassuring.6 Some authorities have proposed making acyclovir available as a nonprescription drug.
Toxicity is rare, but in patients who are dehydrated or who have poor renal function, the drug can crystallize in the renal tubules, leading to a reversible creatinine elevation or, rarely, acute tubular necrosis.
Oral bioavailability is 77 percent, and the drug is quickly converted to its active form.11 Mechanism and efficacy are similar to those of acyclovir.12 Famciclovir's intracellular half-life is 10 times longer than acyclovir's; despite this, dosing less frequently than twice daily is not recommended.13Genital HSV infection is usually transmitted through sexual contact; therefore, it generally does not occur before adolescence.
When genital herpes occurs in a preadolescent, the possibility of abuse must be considered, as with all sexually transmitted diseases in children.
New antiviral medications have expanded treatment options for the two most common cutaneous manifestations, orolabial and genital herpes.Patients who have six or more recurrences of genital herpes per year can be treated with one of the following regimens: acyclovir, 400 mg twice daily; valacyclovir, 1 g daily; or famciclovir, 250 mg twice daily.These regimens are effective in suppressing 70 to 80 percent of symptomatic recurrences.JAMA 1984;247–51Information from Mertz GJ, Critchlow CW, Benedetti J, Reichman RC, Dolin R, Connor J.JAMA 1984;247–51The oral acyclovir dosage for treatment of primary or initial nonprimary genital herpes is 200 mg five times daily for 10 days.