Zoster 800 Tablet contains Acyclovir 800 mg, an antiviral agent indicated for the treatment of herpes zoster (shingles) caused by the varicella-zoster virus. Acyclovir is a synthetic nucleoside analogue that inhibits viral DNA polymerase, thereby preventing viral replication and reducing the severity and duration of the infection. Zoster 800 Tablet is primarily prescribed to manage acute herpes zoster episodes, alleviating pain and promoting faster lesion healing. It may also be used for prophylaxis in immunocompromised patients to prevent varicella-zoster virus reactivation. The recommended dosage for adults typically involves oral administration of 800 mg five times daily for 7 to 10 days, initiated as early as possible after rash onset to maximize therapeutic efficacy. Acyclovir is generally well tolerated; however, adverse effects may include gastrointestinal disturbances, headache, dizziness, and, rarely, nephrotoxicity, particularly in patients with pre-existing renal impairment. Adequate hydration is advised to minimize renal side effects. Caution is warranted in patients with renal dysfunction, and dose adjustments may be necessary. Zoster 800 Tablet should be used under medical supervision, with consideration of patient history and concomitant medications to avoid potential drug interactions. This medication is not effective against latent virus and does not cure herpes infections but helps control symptoms and viral spread.