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A muscle cramp is a sudden, brief, painful contraction of a muscle or group of muscles.

Cramps (charley horses) can occur in healthy people (usually middle-aged and elderly people), sometimes during rest, but particularly during or after exercise. Leg cramps can occur during sleep, causing pain and plantar flexion of the foot and toes.

Tight calf muscles (eg, from lack of stretching, inactivity, or sometimes chronic lower leg edema) are a common cause of leg cramps. Cramps may also be caused by electrolyte abnormalities (eg, hypokalemia). Exertional muscle pain from ischemia due to peripheral arterial disease (claudication) may cause similar calf pain, but this pain is due to inadequate blood flow to muscles and not to a muscle contraction as with a cramp.

Treatment

• Stretching

To relieve a calf cramp, patients can use their hand to pull the toes and foot upward (dorsiflexion).

Measures to prevent cramps include the following:

• Not exercising immediately after eating
• Gently stretching the muscles before exercising or going to bed
• Drinking plenty of fluids (particularly beverages that contain potassium) after exercise
• Not consuming stimulants (eg, caffeine, nicotine Some Trade Names
  COMMIT
  NICORETTE
  NICOTROL
  Click for Drug Monograph
  , ephedrine Some Trade Names
  PRETZ-D
  Click for Drug Monograph
  , pseudoephedrine Some Trade Names
  AFRINOL
  SUDAFED
  Click for Drug Monograph
  )

The runner's stretch is most useful. A person stands with one leg forward and bent at the knee and the other leg behind and the knee straight—a lunge position. The hands can be placed on the wall for balance. Both heels remain on the floor. The knee of the front leg is bent further until a stretch is felt along the back of the other leg. The greater the distance between the two feet and the more the front knee is bent, the greater the stretch. The stretch is held for 30 sec and repeated 5 times. The set of stretches is repeated on the other side.

Most of the drugs prescribed to prevent cramps (eg, quinine Some Trade Names
QUALAQUIN
Click for Drug Monograph
, magnesium, benzodiazepines) have no demonstrated efficacy and are not recommended. Mexiletine Some Trade Names
MEXITIL
Click for Drug Monograph
sometimes helps, but whether using it is worth the risk of adverse effects is unclear. These include nausea, vomiting, heartburn, and dizziness and tremor. Ca supplements are safe and have few side effects but have not proved effective.

If a cramp occurs, stretching the affected muscle often relieves the cramp. For example, for a calf cramp, the person could use a hand to pull the foot and toes upward or do the runner's stretch.

Last full review/revision May 2008 by Joseph J. Biundo, MD

Content last modified May 2008