A literature search from 1993 to 1997 using MEDLINE and key-words beverages,
muscle cramp, and
quinine was performed. Three beverages containing
quinine were examined in grocery stores. Analysis indicate that leg
cramps are a common phenomenon associated with many comorbid disorders especially peripheral vascular and
neurologic disorders. Thus, evaluation of a patient's complaining of leg
cramps appropriately includes vascular, neurologic, and musculoskeletal examinations. Laboratory investigation of the symptom of leg
cramps warrants as a minimum, assessment of thyroid function and determination of platelet counts and serum levels of
electrolytes,
calcium, and
magnesium. A few small studies suggest that
quinine is effective in decreasing the frequency of
nocturnal leg cramps but not their severity or duration.
Quinine consumed in commercial beverages has been reported to cause potentially fatal immunologically mediated
hypersensitivity reactions. The concentration of
quinine in commercial beverages varies greatly. Although commercial beverages containing
quinine generally are labeled "Contains
quinine," they typically lack both nutritional information about the amount of
quinine and warnings of the health risks. It appears that 325 milligrams of
quinine taken by mouth at bedtime typically relieves
nocturnal leg cramps, but lower starting doses are appropriate for senior citizens and individuals with impaired renal function. In general,
quinine in any form should be avoided by pregnant women and people with
hepatic failure.
Quinine consumed for the treatment of leg
cramps should be prescribed and monitored by physicians, and people who consume
quinine in commercial beverages must be warned of the health risks.