Heviran (Aciclovir)

Heviran (aciclovir) is prescribed for several viral infections where herpes viruses are implicated.

• Treatment of oral and genital herpes simplex virus infections, including cold sores and recurrent genital lesions.
• Management of varicella‑zoster virus infection, commonly known as shingles, to reduce pain and speed healing.
• Prevention of herpes zoster reactivation in immunocompromised individuals, such as transplant recipients.
• Post‑exposure prophylaxis for herpes simplex virus in high‑risk exposures.

• Aciclovir is a nucleoside analogue that is selectively phosphorylated by viral thymidine kinase to aciclovir monophosphate, then further converted by cellular kinases to the active triphosphate form. The triphosphate competitively inhibits viral DNA polymerase and becomes incorporated into viral DNA, causing premature chain termination and preventing viral replication without significantly affecting host DNA synthesis. Because the drug requires viral kinase for activation, it accumulates preferentially in infected cells, enhancing its selectivity.

Adverse reactions to Heviran are generally mild, but serious events can occur, especially in susceptible individuals.

Common

• Nausea or vomiting, usually transient
• Diarrhea, mild to moderate intensity
• Headache, often resolves without treatment
• Fatigue or general weakness

Serious

• Acute kidney injury, especially in patients with pre‑existing renal impairment or dehydration
• Severe allergic reactions, including rash, Stevens‑Johnson syndrome, or anaphylaxis
• Blood‑cell disorders such as neutropenia, thrombocytopenia, or anemia
• Central nervous system effects, including confusion, hallucinations, or seizures, more common in the elderly or with high plasma levels

Before initiating Heviran, clinicians should evaluate several safety considerations to minimize risk.

• Assess renal function; dose adjustment may be required in patients with impaired kidney clearance.
• Review patient history for hypersensitivity to aciclovir or related nucleoside analogues.
• Use caution in immunocompromised individuals, as viral resistance can develop.
• Monitor for signs of neurotoxicity, particularly in the elderly or those with renal dysfunction.
• Consider pregnancy and breastfeeding status; limited data are available, so risk‑benefit assessment is essential.
• Avoid concurrent use of nephrotoxic drugs without appropriate monitoring.

Heviran may interact with other medicines, altering its effectiveness or increasing toxicity.

Avoid

• Co‑administration with other nephrotoxic agents such as aminoglycosides or amphotericin B without renal monitoring.
• Concurrent use of probenecid, which can markedly increase aciclovir plasma concentrations.

Use with caution

• Non‑steroidal anti‑inflammatory drugs (NSAIDs) that may affect renal function.
• Cimetidine or other H2‑blockers, which can modestly raise aciclovir levels.
• Immunosuppressants like cyclosporine, where viral resistance may be more likely.
• Live vaccines, as antiviral therapy could reduce vaccine efficacy.