Clinical features and management of adverse effects of quinolone antibacterials

The quinolone antibacterials are proving very useful in the management of infection, notably for the treatment of Gram-negative bacteria. With the increasing use of these drugs, adverse effects are being recognised more often and careful documentation is still required. In general, the quinolones are of low toxicity. Gastrointestinal adverse effects are the most common, and are usually mild; indeed, all adverse events are generally mild and resolve on withdrawal of the offending drug. Certain precautions and contraindications are apparent. Because drug-induced arthropathies occur in juvenile animals, quinolones should not be administered to pregnant or lactating women or to growing children, unless the clinical benefit outweighs the risk. Caution should also be observed in patients with previous epilepsy or severe cerebral arteriosclerosis. Neurological effects may require the use of appropriate neuro- and psychoactive drugs, as well as the withdrawal of the precipitating agent. Hypersensitivity reactions to a fluoroquinolone may require the use of antihistamines, and in some cases topical or systemic steroids, and may well preclude future use of a fluoroquinolone. Dose adjustments may be necessary in patients with reduced renal function, when the measurement of serum concentrations may be desirable. Interstitial nephritis, haematuria and acute renal failure are rare effects of quinolone therapy which will require appropriate management including withdrawal of the precipitating drug. Interactions with theophylline and warfarin are of clinical significance, and may require plasma concentration monitoring and adjustment of dosage.