Zorivax 400 Tablet contains Acyclovir 400 mg, an antiviral agent primarily indicated for the treatment of infections caused by herpes viruses, including herpes simplex virus types 1 and 2, varicella-zoster virus, and cytomegalovirus. Acyclovir acts by inhibiting viral DNA synthesis, thereby preventing viral replication and reducing the severity and duration of outbreaks. It is commonly prescribed for the management of genital herpes, cold sores, shingles, and chickenpox. Zorivax 400 Tablet is administered orally and is absorbed variably in the gastrointestinal tract, with bioavailability enhanced by adequate hydration. Dosage regimens vary depending on the type and severity of infection, patient age, and renal function, necessitating dose adjustments in cases of renal impairment. The medication is generally well tolerated; however, adverse effects may include headache, nausea, diarrhea, and, rarely, nephrotoxicity or neurotoxicity, particularly in patients with compromised renal function. It is contraindicated in patients with known hypersensitivity to acyclovir or valacyclovir. Caution is advised during pregnancy and lactation, and use should be guided by a healthcare professional. Zorivax 400 Tablet should be stored at room temperature, away from moisture and direct sunlight, to maintain its efficacy.