Review of Nocturnal Cramps and Introduction of a Novel Topical Therapy

Abstract

Nocturnal leg and foot cramps are reported by more than half of the U.S. population over age 50, with varying frequency, but of those reporting the ailment, up to 20% experience nightly episodes, with attendant sleep disruption which can exacerbate other medical conditions.   While there is a widespread belief, even among many clinicians, that hypohydration and electrolyte depletion from exercise are the primary causes of leg cramps, there is strong evidence that neither of these is a primary factor in either exercise-induced or nocturnal muscle cramping.  Many commonly used prescription drugs have an impact on muscle physiology and can cause or exacerbate cramps.  There is good evidence that the physiological and neurological impact of muscle fatigue, and associated changes in muscle biochemistry, including lactic acid accumulation, are one key factor in nocturnal cramping.  A new topical approach to the condition has shown early evidence of its potential to address nocturnal cramping, due to its demonstrated ability to increase oxygen availability and reduce lactic acid levels in muscle tissue.

Nocturnal cramps represent a common medical challenge in patients age 50 and up, with a higher incidence as individuals age⁽¹⁾.  Up to 60% of adults over 50 years of age report a history of night cramps, usually in the calf or thigh, but sometimes the foot.  Up to 20% of those experiencing nocturnal cramps have nightly episodes, which can be severe enough to warrant medical treatment.⁽²⁾  While nocturnal cramping is not as common in younger populations, 7% of children in one study had experienced at least one cramping episode within the prior 12 months.⁽³⁾ 

Nocturnal cramping episodes vary in severity, but for many patients the experience is both painful and debilitating.  While the average duration of a nocturnal cramp is nine minutes, the initial event is frequently followed by recurrent episodes and residual pain that may last for up to one week.⁽⁴⁾  For many older patients, nocturnal cramping is a nightly experience, and the attendant sleep disruption can exacerbate other medical conditions, including a negative impact on immune response, cognitive ability, and cardiovascular health.^(5,6,7)