The frequency categories associated with the adverse events as follows are estimates. For most events, suitable data for estimating incidence were not available. In addition, adverse events may vary in their incidence depending on the indication.
The following convention has been used for the classification of adverse effects in terms of frequency: Very common ≥1/10, common ≥1/100 and <1/10, uncommon ≥1/1000 and <1/100, rare ≥1/10,000 and <1/1000, very rare <1/10,000.
Blood and Lymphatic System Disorders: Very Rare: Anaemia, leukopenia, thrombocytopenia.
Immune System Disorders: Rare: Anaphylaxis.
Psychiatric and Nervous System Disorders: Common: Headache, dizziness. Very Rare: Agitation, confusion, tremor, ataxia, dysarthria, hallucinations, psychotic symptoms, convulsions, somnolence, encephalopathy, and coma.
The previously mentioned events are generally reversible and usually reported in patients with renal impairment, or with other predisposing factors (see Precautions).
Respiratory, Thoracic and Mediastinal Disorders: Rare: Dyspnoea.
Gastrointestinal Disorders: Common: Nausea, vomiting, diarrhoea, abdominal pains.
Hepatobiliary Disorders: Rare: Reversible rises in bilirubin and liver related enzymes. Very Rare: Hepatitis, jaundice.
Skin and Subcutaneous Tissue Disorders: Common: Pruritus, rashes (including photosensitivity). Uncommon: Urticaria. Accelerated diffuse hair loss.
Accelerated diffuse hair loss has been associated with a wide variety of disease processes and medicines, the relationship of the event to aciclovir therapy are uncertain.
Renal and Urinary Disorders: Rare: Increases in blood urea and creatinine. Very Rare: Acute renal failure, renal pain.
Renal pain may be associated with renal failure.
General Disorders and Administration Site Conditions: Common: Fatigue, fever.