Aciclovir (genital herpes)

Overview

Antiviral for genital herpes — controls episodes and (as suppression) reduces recurrences/transmission, but does NOT eradicate the latent virus.

Mechanism

Guanosine analogue — phosphorylated by viral thymidine kinase then host kinases → aciclovir triphosphate inhibits viral DNA polymerase and chain-terminates → blocks HSV/VZV replication (selective for infected cells).

Indications

• First-episode genital herpes (400 mg TDS 5 days)
• Recurrent episodes (episodic therapy)
• Suppressive therapy (≥6 recurrences/year, or to reduce transmission)
• HSV in pregnancy (from 36 weeks to reduce shedding)

Adverse effects

Cautions & contraindications

Interactions

• Nephrotoxins; probenecid raises levels

Monitoring & kinetics

Symptom control; not curative — counsel re latency/recurrence/transmission

Oral (valaciclovir = better-absorbed prodrug); IV for severe/disseminated.