Quinolone adverse effects

As with all drugs, the specific side effects of the quinolones must be considered when they are chosen for treatment of bacterial infections [5]. Reactions of the gastrointestinal tract and the central neivous system are the most often observed adverse effects during therapy with quinolones. It should be underlined, however, that compared with many other antimicrobials, diarrhea is less frequently observed during quinolone treatment. Antibiotic-associated colitis has been observed rarely during quinolone therapy. Similarly, hypersensitivity reactions, as observed during therapy with penicillins and other (3-lactams, is less frequently caused by quinolones. Some other risks of quinolone therapy have been defined and must be considered if a drug from this class is chosen for treatment of bacterial infections. 

Stahlmann R, Lode H (2000) Safely overview. Toxicity, adverse effects, and interactions. In Andriole V (ed) Hie Quinolones. 3rd edn. London, Academic Press, pp 397-453... 

In summary, the adverse effects associated with the quinolones appear presently to be mild to moderate in severity and reversible upon discontinuation of therapy. Severe systemic adverse reactions are rare [62], It is suggested that the use of these agents should be avoided, as far as possible, in children and pregnant women and that caution be used in their administration to patients with a seizure disorder or those taking theophylline or warfarin [62]. Articles suggesting the appropriate clinical usage for these important antibacterials have appeared [64],... 

The potential for sunlight (or selected other light frequencies) to transform a drug or product is both a useful tool for activating some drugs and a cause of significant adverse effects for others (such as the quinolone antibiotics [Horio et al., 1995 and... 

With IV CyC - - 5FU - - MTX it cannot be established which IMN in the combination is effective and which induces adverse effects. Immediate allergic reactions arising during IV drips may indicate the IMN concerned. Drug interactions among 5FU, MTX and CyC by IVT and oral CyS, MMF, and MTX have not been studied. It has been established however that quinolone antibiotics may interact with IMNs. 

Summary of therapeutic advantages and adverse effects of quinolones. 

The main systems affected by adverse effects of the quinolones are the skin, liver, and nervous system. The best-known adverse effect is phototoxicity, the risk of which varies markedly among the quinolones lomefloxacin and sparfloxacin carry a particularly high risk. The development of phototoxicity is based on an interaction between hght and the drug. Neurotoxicity also occurs, with marked variation of incidence between the various compounds. Hypersensitivity reactions to quinolones are rare, and include anaphylactic shock and anaphylactoid reactions. Organ-specific reactions attributed to hypersensitivity involve the liver and kidneys. If hypersensitivity reactions occur, switching from one qui-nolone compound to another is probably not advisable, since there is cross-reactivity. 

What is the most common adverse effect of quinolone administration ... 

For ciprofloxacin, there is a marked tenfold increase in exposure to tizanidine, with a consequent increase in adverse effects. Some authors recommend that this combination be avoided, whereas others recommend caution. The US manufacturer contraindicates the combination, whereas the UK manufacturers do not mention this potential interaction. If ciprofloxacin is considered the most appropriate antibacterial to use in a patient already taking tizanidine, anticipate the need to reduce the tizanidine dose before starting the ciprofloxacin, and closely monitor adverse effects starting ciprofloxacin may cause marked hypotension, bradycardia, and sedation. Other quinolones also inhibit CYP1A2, but to varying degrees, see Table 33.4 , (p. 1193). 

The quinolones have been found to cause erosion of cartilage in the joints of immature animals [56]. This observation, which has been seen in several studies, has resulted in the contraindication of quinolones for the treatment of children. A study analyzing the risk-benefit situation for the use of pefloxacin in children (clinically, several adverse athralgic effects have been attributed to this agent) has appeared [57]. The underlying mechanism responsible for these effects has yet to be established, and the development of an agent which is safe for paediatric use would be a major advance in quinolone therapy. Some of the quinolones, such as enoxacin, have been shown to interfere with theophylline metabolism [58], and side-effects associated with this agent may be related to this property. 

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