|The frequency of adverse events listed below is defined using the following convention:Very common (≥1/10); common (≥1/100 to < 1/10); uncommon (≥1/1,000 to < 1/100); rare (≥1/10,000 to < 1/1,000); very rare (< 1/10,000), not known (cannot be estimated from the available data).Serious adverse reactions occur rarely with standard recommended regimens. Clinicians who contemplate continuous therapy for the relief of chronic conditions, for periods longer than those recommended, are advised to consider the possible therapeutic benefit against the risk of peripheral neuropathy.|
Blood and lymphatic system disorders: Very rare: agranulocytosis, neutropenia, thrombocytopenia, and pancytopenia Not known: leucopenia.
Immune system disorders: Rare: anaphylaxis,Not known: angioedema, urticaria, fever.
Metabolism and nutrition disorders: Not known: anorexia.
Psychiatric disorders: Very rare: Psychotic disorders, including hallucinations. Not known: depressed mood
Nervous system disorders: Very rare: Encephalopathy (eg. confusion, fever, headache, hallucinations, paralysis, light sensitivity, disturbances in sight and movement, stiff neck) and subacute cerebellar syndrome (eg. ataxia, dysathria, gait impairment, nystagmus and tremor) which may resolve on discontinuation of the drug. Drowsiness, dizziness, convulsions, headaches Not known: during intensive and/or prolonged metronidazole therapy, peripheral sensory neuropathy or transient epileptiform seizures have been reported. In most cases neuropathy disappeared after treatment was stopped or when dosage was reduced. Aseptic meningitis
Eye disorders: Very rare: diplopia, myopia, in most cases transient. Not known: optic neuropathy/neuritis
Gastrointestinal disorders: Not known: Taste disorders, oral mucositis, furred tongue, nausea, vomiting, gastro-intestinal disturbances such as epigastric pain and diarrhoea.
Hepatobiliary disorders: Very rare: abnormal liver function tests, cholestatic hepatitis, jaundice and pancreatitis which is reversible on drug withdrawal.
Skin and subcutaneous tissue disorders: Very rare: skin rashes, pustular eruptions, pruritis, flushing Not known: erythema multiforme. Musculoskeletal, connective tissue and bone disorders: Very rare: myalgia, arthralgia.
Renal and urinary disorders: Very rare: darkening of urine (due to metronidazole metabolite).