The FDA recently issued a second warning against treating nocturnal leg cramps with a quinine product called Qualaquin (quinine sulfate). Using Qualaquin for leg cramps is "off-label" as it is only approved for uncomplicated Malaria infection - a very different disorder than nocturnal leg cramps.
The FDA has been getting reports of bleeding dirorders from Qualaquin use. One of the bleeding disorders has been linked to severe kidney disease.
Nocturnal or night-time leg cramps can be a real sleep destroyer. This disorder is more common in older individuals and can produce very painful muscle cramps, usually in the calves. It can wake someone from sleep, contributing to insomnia. Doctors and patients have used quinine for decades until the past few years, when the FDA warned against its use due to irregular heart beat. Now, there appears to be another reason to be more careful when using quinine for leg cramps.
In some cases, leg cramps that wake people from sleep are due to electrolyte and/or mineral deficiencies, like magnesium or potassium. Replacing those that are deficient can often reduce or eliminate the night-time leg cramps. A simple blood test can help your doctor determine if your electrolyte or mineral levels are too low, and possibly contributing to night-time leg cramps.