Type of Medication: Antibiotic

Indications: Treatment and prophylaxis of herpes simplex and varicella zoster

Side Effects: Optic neuritis, red/green colour blindness, peripheral neuritis, rash. Pruritis, urticaria, thrombocytopenia, gastrointestinal upset. Visual disturbance is more common if excessive doses are used or in renal impairment. Patients should stop treatment and seek advice if any deterioration in eyesight develops.  

Route of administration: Adult (Oral)

Dose:15mg/kg daily (unsupervised) 30mg/kg 3 x week (supervised) 2 month initial phase only. Can be ommitted if risk of isoniazid resistance low ie. no previous treatment with isoniazid, not immunosuppressed and not in contact with orgs likely to be drug resistant.

Administration: Reduce dose in renal impairment (CrCl <30ml/min)and monitor plasma levels. Aim Peak concentration (2-2.5 hours after dose) 2-6mg/L (7-22micromol/L). Trough (pre-dose) <1 mg/l (4micromol/l) Available as 100mg and 400mg tablets.

Route of administration: Paediatric (Oral)

Dose: Dose as adult. Care should be taken in children under 5 years of age due to difficulty testing eyesight and obtaining reports of visual symptoms

Administration: As Adult A manufactured special suspension of 400mg/5ml is available from Nova Laboratories, Leicester.

Examples of some Drug Interactions

Interacting drug: Mycophenylate Mofetil

increases levels of both drugs

Interacting drug: Probenecid

reduces aciclovir excretion