Prescribing Notes
Quinine
- Quinine is very toxic in overdosage and accidental fatalities have occurred. Trials show patients experience only one less episode per week taking quinine compared with placebo and that cramp duration is not significantly affected. It is not recommended for treating idiopathic leg cramps due to poor benefit-to-risk ratio. See MHRA.
- Prescribers are advised to only consider quinine:
- when cramps are very painful or frequent
- when other treatable causes of cramp have been ruled out
- when non-pharmacological measures (e.g. passive stretching exercises) have been ineffective
- Monitor closely during early treatment for adverse effects including unpredictable, serious and life-threatening thrombocytopenia, cinchonism (even at therapeutic doses) and hypoprothrombinaemia.
- Treatment should be stopped if there is no benefit after an initial trial of four weeks. If treatment continues, benefit should be assessed every 3 months. In patients taking quinine long term, a trial discontinuation should be considered – Quinine Prescribing Review Tool.
- Quinine should be used with caution in people with risk factors for QT prolongation, taking other medicines that could prolong the QT interval or in those with atrioventricular block. For further details see MHRA.