The following convention has been used for the classification of undesirable 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:
Psychiatric and nervous system disorders:
Common: Headache, dizziness.
Very rare: Agitation, confusion, tremor, ataxia, dysarthria, hallucinations, psychotic symptoms, convulsions, somnolence, encephalopathy, coma.
The previously mentioned events are generally reversible and usually reported in patients with renal impairment or with other predisposing factors.
Respiratory, thoracic and mediastinal disorders:
Common: Nausea, vomiting, diarrhoea, abdominal pains.
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 is 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 and crystalluria.
General disorders and administration site conditions:
Common: Fatigue, fever.