Nocturnal leg cramps
Drug Safety Update
Quinine has been used in the UK for the treatment of nocturnal leg cramps for many years. Although patient response may vary, overall efficacy is modest, the frequency of nocturnal leg cramps is reduced by about 25% in ambulatory patients - around one episode a week difference.
The MHRA advises that quinine is not a routine treatment for nocturnal leg cramps and should only be used if cramps cause regular disruption of sleep. Consider quinine only when cramps are very painful or frequent; when other treatable causes of cramp have been ruled out, and when non-pharmacological measures have not worked, (e.g. passive stretching exercises). After an initial trial of 4 weeks, treatment should be stopped if there is no benefit.
Initially patients should be monitored closely for adverse effects as well as benefit. Treatment should be interrupted at 3-monthly intervals to assess the need for further quinine. In patients taking quinine long-term, a trial discontinuation may be considered.
Please note that quinine bisulphate 300mg is approximately equivalent to quinine sulphate 200mg, so the salt should always be specified.