Quinine for muscle cramps linked to increased mortality

Long-term use of quinine for nocturnal leg cramps may increase the risk of mortality, a study of UK GP prescribing published in JAMA has found.

Quinine has been used in the UK for the treatment of nocturnal leg cramps for many years. | SCIENCE PHOTO LIBRARY
Quinine has been used in the UK for the treatment of nocturnal leg cramps for many years. | SCIENCE PHOTO LIBRARY

Researchers from the UK and France used data from the Health Improvement Network database from general practices in the UK. Of 175,195 patients included in their analysis, approximately a quarter (44,699) had been prescribed quinine for idiopathic muscular cramps or restless leg syndrome for at least one year.

The median daily quinine dose was 203mg. Over a median follow-up period of 5.7 years, quinine exposure was associated with 4.2 deaths per 100 person–years, compared with a rate of 3.2 deaths per 100 person–years for unexposed individuals (adjusted hazard ratio 1.24, CI 1.21–1.27). These findings suggest the risk of death could be significantly increased with long-term use of quinine.

Poor risk–benefit ratio

The authors acknowledge that their findings could reflect unmeasured confounders that may predispose patients to higher mortality. However, they concluded, "the benefits of quinine in reducing cramps should be balanced against the risks."

Owing to the poor benefit-to-risk ratio, both NICE CKS and the MHRA advise that quinine should not be considered a routine treatment for nocturnal leg cramps, and should only be considered when self-care measures fail and cramps cause regular disruption of sleep.

If GPs choose to prescribe quinine for this indication, CKS recommends a dose of 200–300mg at bedtime for 4–6 weeks. If this is beneficial, treatment may be continued with review every 3–6 months.

Want news like this straight to your inbox?
Sign up for our bulletins

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Already registered?
Sign in

More from MIMS

Drug shortages - live tracker

Use our constantly updated shortages tracker to check...

Logo of the webinar

Cow's Milk Allergy in Practice: free webinar series for UK healthcare professionals

Join us for a short webinar series offering insights...

Close up image of multicoloured capsules

MIMS antidepressants table updated

The MIMS table 'Antidepressants, a guide to switching...

Purple, orange, blue and yellow blood test tubes on a tray.

New advice on vitamin B12 monitoring in patients taking metformin

Patients on metformin treatment with risk factors for...