Valacyclovir dosage

Transmission-The recommended dosage of valacyclovir for reduction of transmission of genital herpes in patients with a history of 9 or fewer recurrences per year is 500 mg once daily for the source partner. Counsel patients to use safer sex practices P.1041... 

HIV-infected patients In HIV-infected patients with CD4 cell count at least 100 cells/mm, the recommended dosage of valacyclovir for chronic suppressive therapy of recurrent genital herpes is 500 mg twice daily. The safety and efficacy of therapy with valacyclovir beyond 6 months in patients with HIV infection have not been established. 

Herpes labialis The recommended dosage of valacyclovir for the treatment of cold sores is 2 g twice daily for 1 day taken approximately 12 hours apart. Initiate therapy at the earliest symptom of a cold sore (eg, tingling, itching, burning). There are no data on the effectiveness of treatment initiated after the development of clinical signs of a cold sore (eg, papule, vesicle, ulcer). Therapy beyond 1 day does not appear to provide additional clinical benefit. 

Renai function impairment Dosage reduction is recommended with renal impairment (see Administration and Dosage). Acute renal failure and CNS symptoms have been reported in patients with underlying renal disease who have received inappropriately high doses for their level of renal function. Exercise similar caution when administering valacyclovir to elderly patients and patients receiving potentially nephrotoxic agents. 

Hepatic function impairment Administration of valacyclovir to patients with moderate (biopsy-proven cirrhosis) or severe (with and without ascites and biopsy-proven cirrhosis) liver disease indicated that the rate but not the extent of conversion of valacyclovir to acyclovir was reduced, and the acyclovir half-life was not affected. Dosage modification is not recommended for patients with cirrhosis. 

Valacyclovir is generally well tolerated, although nausea, vomiting, or rash occasionally occur. At high doses, confusion, hallucinations, and seizures have been reported. AIDS patients who received high-dosage valacyclovir chronically (ie, 8 g/d) had an increased incidence of gastrointestinal intolerance as well as thrombotic thrombocytopenic purpura and hemolytic-uremic syndrome this dose was associated with confusion and hallucinations in transplant patients. 

The main side effect associated with oral acyclovir, valacyclovir, and femciclovir is intestinal disturbance such as nausea and vomiting. Acyclovir is available in an 800-mg tablet that does not contain lactose therefore it is less likely to cause lactose-related diarrhea. Lower dosages are recommended for treatment of elderly patients with impaired creatinine clearance. Perhaps the most significant factor in fevor of antivirals is that they minimize the common complications of the disease, including dendriform keratopathy, stromal keratitis, and anterior uveitis. 

Systemic antiviral therapy promotes resolution of HZO skin lesions and reduces the incidence and severity of dendriform keratopathy, anterior uveitis, and stromal keratitis by decreasing the rate of virus replication. All patients with acute HZO should receive antiviral therapy with the goal of minimizing ocular complications. Acyclovir, valacyclovir, and femciclovir are FDA approved for management of herpes zoster. Acyclovir usually is administered orally in dosages of 800 mg five times per day far 7 days. Valacyclovir has better bioavailability when taken orally and can be used with a recommended dosage of 1 g three times a day for 7 days. Famciclovir, which has bioavailability similar to valacyclovir, has an increased half-life and also has the advantage of less frequent administration than acyclovir 500 mg three times a day for 7 days. 

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