Aciclovir 800 mg tablets are indicated for: the treatment of Herpes simplex virus infections of the skin and mucous membranes including initial and recurrent genital herpes; the suppression (prevention of recurrences) of recurrent Herpes simplex infections in immune-competent patients; the prophylaxis of Herpes simplex infections in immune-compromised patients; the treatment of Varicella infections (chickenpox) and Herpes zoster (shingles). Studies have shown that early treatment of shingles with aciclovir has beneficial effect on pain and can reduce the incidence of post-herpetic neuralgia (zoster-associated pain); the management of certain severely immunocompromised patients, namely those with advanced HIV disease (CD4+ counts <200/mm3, including patients with AIDS or severe ARC) or following bone marrow transplantation. Studies have shown that oral aciclovir given conjunction with antiretroviral therapy (mainly oral Zidovudine) reduced mortality in patients with advanced HIV disease and that oral aciclovir preceded by one month's treatment with intravenous aciclovir reduced mortality in bone marrow transplant recipients. In addition oral aciclovir provided effective prophylaxis for herpes virus disease.