In this section, frequencies of undesirable effects are defined as follows: Frequency: very common (>1/10); common (>1/100, <1/10); uncommon (>1/1,000, <1/100); rare (>1/10,000, <1/1,000), very rare (<1/10,000).
Blood & lymphatic system disorders:
Rare: Thrombocytopenia
Very rare: Leucopenia, neutropenia
Immune system disorders:
Very rare: Hypersensitivity, anaphylactoid reactions, (see also Skin and subcutaneous tissue disorders)
Metabolic & nutrition disorders:
Uncommon: Hyperuricaemia
Very rare: Gout
Nervous system disorders:
Rare: Peripheral neuropathy, numbness, paraesthesia of the extremities
Very rare: headache, dizziness, disorientation
Psychiatric disorders:
Very rare: mental confusion, hallucinations
Eye disorders
Uncommon: Optic neuritis (decreased visual acuity, loss of vision, scotoma, colour blindness, visual disturbance, visual field defect, eye pain)
Respiratory, thoracic & mediastinal disorders:
Very rare: Pneumonitis, pulmonary infiltrates, with or without eosinophilia
Gastrointestinal disorders:
Gastrointestinal disorders such as anorexia, nausea, vomiting, abdominal pain and diarrhoea have been noted in patients on multiple drug anti-tuberculosis therapy including ethambutol although not in test patients receiving ethambutol as sole therapy.
Hepatobiliary disorders:
Hepatic reactions with hepatitis, jaundice, abnormal liver function test values, and very rarely, hepatic failure, have been reported in patients treated with multiple drug therapy including ethambutol. Liver function tests should be performed in patients who develop symptoms suggestive of hepatitis or who become generally unwell during treatment.
Skin & subcutaneous tissue disorders:
Rare: Rash, pruritus, urticaria Very rare: photosensitive lichenoid eruptions, bullous dermatitis, Stevens-Johnson syndrome, epidermal necrolysis
Frequency not known: Drug reaction with eosinophilia and systemic symptoms (DRESS) (see section 4.4)
Musculoskeletal and connective tissue disorders:
Very rare: Joint pains
Renal & urinary disorders
Very rare: Interstitial nephritis
General disorders and administration site conditions:
Very rare: Malaise, pyrexia
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for 'MHRA Yellow Card' in the Google Play or Apple App Store.