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Reversible neurological reactions, notably dizziness, confusion states, hallucinations, somnolence and convulsions, have occasionally been reported, usually in patients with renal impairment in whom the dosage was in excess of that recommended or with other predisposing factors.
Short-term administration for genital herpes. Nausea and/or vomiting and headache were the most frequent adverse effects. Less frequent (< 1%) reactions included diarrhoea, dizziness, anorexia, fatigue, oedema, skin rashes, leg pain, inguinal adenopathy, medication taste and sore throat. Occasional changes in hepatic enzymes and changes in haematological parameters were also noted.
Long-term suppressive therapy for genital herpes. Nausea and/or vomiting, headache, diarrhoea, vertigo and arthralgia were the most frequent adverse effects. Less frequent adverse effects included skin rash, insomnia, fatigue, fever, palpitation, sore throat, superficial thrombophlebitis, muscle cramps, pars planitis, menstrual abnormalities, lymphadenopathy, irritability, accelerated hair loss, depression and occasional increases in hepatic enzymes.
Herpes zoster. The most commonly reported adverse effect was gastrointestinal disturbance. Other reports included aching, chest pain, confusion, constipation, diarrhoea, giddiness, hallucinations, headache, insomnia, nausea, rash, shaking, taste disturbance, tremor, vertigo and malaise, vomiting and mental status alteration. Significantly, the overall incidence of side effects reported was the same in patients on placebo.
Advanced symptomatic HIV disease. In patients receiving antiretroviral therapy (mainly oral zidovudine), no significant overall increase in toxicity was associated with the addition of aciclovir. However, moderate increases in anaemia and neutropenia were seen in some studies in patients with advanced HIV disease.
The frequency categories associated with the adverse events below 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 undesirable effects in terms of frequency: very common greater than or equal to 1/10; common greater than or equal to 1/100 and < 1/10; uncommon greater than or equal to 1/1,000 and < 1/100; rare greater than or equal to 1/10,000 and < 1/1,000; very rare < 1/10,000.
Blood and lymphatic system disorders. Very rare: anaemia, leucopenia, thrombocytopenia.
Immune system disorders. Rare: anaphylaxis.
Psychiatric and nervous system disorders. Common: headache, dizziness, confusion, hallucinations, somnolence, convulsions. Very rare: agitation, tremor, ataxia, dysarthria, psychotic symptoms, encephalopathy, coma.
The above events are reversible and usually reported in patients with renal impairment in whom the dosage was in excess of that recommended, or with other predisposing factors.
Vascular disorders. Common: phlebitis.
Respiratory, thoracic and mediastinal disorders. Rare: dyspnoea.
Gastrointestinal disorders. Common: nausea, vomiting, diarrhoea, abdominal pain.
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 is uncertain. Rare: angioedema.
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.