Can chloroquine cause drop foot?/nA woman with polymyalgia rheumatica has been treated with cortiso

Fråga: Can chloroquine cause drop foot? A woman with polymyalgia rheumatica has been treated with cortisone since one year. In order to reduce the cortisone dose chloroquine was introduced six months ago. The patient now has a drop foot.

Sammanfattning: Chloroquine is neurotoxic and can therefore not be ruled out as the cause of drop foot.

Svar: The regional drug information centre in Sweden (1-6) has previously answered this question. Chloroquine is neurotoxic and can give rise to neuromyopathy, especially in higher doses (> 250 mg/day) and with treatment during long periods (1). However there are a few reports of neuromyopathic side effects at doses normally used in malariaprophylaxis (5). The neuromyopathy is characterised by slow and progressive muscle weakness, initially in the proximal muscles in lower extremity (5). The mechanism of this side effect is unknown (3).

Drop foot is usually due to an injury to the fibular nerve (7). A search in SWEDIS (Swedish Adverse Drug Reactions Advisory Committees database), Intdis (the WHO adverse drug reactions database), Medline and pharmacological handbooks revealed several cases of neuromyopathic adverse effects of chloroquine but no case of drop foot was found.

We recommend this case be reported to SADRAC (Swedish Adverse Drug Reactions Advisory Committee).