The following convention has been utilised for the classification of undesirable effects: very common (≥1/10), common (≥1/100, <1/10), uncommon (≥1/1000, <1/100), rare (≥1/10,000 to <1/1000), very rare (<1/10,000). Adverse event frequencies have been estimated from spontaneous reports from post-marketing data.
Blood & Lymphatic System Disorders: Very Rare: Blood count changes (leucopenia, thrombocytopenia). These are usually reversible. Agranulocytosis or pancytopenia, sometimes with marrow hypoplasia or marrow aplasia.
Immune System Disorders: Rare: Hypersensitivity reactions (urticaria, angioneurotic oedema, fever, bronchospasm, hypotension and chest pain). Very Rare: Anaphylactic shock.
These events have been reported after a single dose.
Psychiatric Disorders: Very Rare: Reversible mental confusion, depression and hallucinations.
These have been reported predominantly in severely ill and elderly patients.
Nervous System Disorders: Very Rare: Headache (sometimes severe), dizziness and reversible involuntary movement disorders.
Eye Disorders: Very Rare: Reversible blurred vision.
There have been reports of blurred vision, which is suggestive of a change in accommodation.
Cardiac Disorders: Very Rare: As with other H2 receptor antagonists bradycardia, A-V block and, with the injection only, asystole.
Vascular Disorders: Very Rare: Vasculitis.
Gastrointestinal Disorders: Very Rare: Acute pancreatitis, diarrhoea.
Hepatobiliary Disorders: Rare: Transient and reversible changes in liver function tests. Very Rare: Hepatitis (hepatocellular, hepatocanalicular or mixed) with or without jaundice, these were usually reversible.
Skin and Subcutaneous Tissue Disorders: Rare: Skin rash. Very Rare: Erythema multiforme, alopecia.
Musculoskeletal and Connective Tissue Disorders: Very Rare: Musculoskeletal symptoms such as arthralgia and myalgia.
Renal and Urinary Disorders: Very rare: Acute interstitial nephritis.
Reproductive System and Breast Disorders: Very Rare: Reversible impotence, breast symptoms and breast conditions (such as gynaecomastia and galactorrhoea).