Leg cramps happen involuntarily when a tightening, spasm, or contraction occurs in your muscles. Leg cramps (also known as a charley horse) can be painful and may temporarily reduce your ability to use the affected leg. Leg cramps often happen just as you’re falling asleep or just as you're waking up. The cramps happen most often in the calf muscle. Leg cramps are very common and many people have them after overworking a muscle or not moving for a long time. Dehydration; pregnancy; low blood sugar, calcium, or potassium levels; alcohol use; neuromuscular disorders such as Parkinson’s disease; and certain medicines also can cause leg cramps.

The following treatments for breast cancer can cause leg cramps:

• tamoxifen, a hormonal therapy
• Evista (chemical name: raloxifene), a hormonal therapy

Managing leg cramps

If you’re having a leg cramp, try the following to ease it:

• Walk around. Using the affected leg may stretch the muscle and make it stop contracting.
• Massage the muscle to relieve the spasm.
• Straighten your leg and flex your foot back toward your body to stretch the calf muscle.
• Place a cold pack on the cramping muscle to help ease the pain.
• A hot bath can relax muscles and stop the cramping.

To help prevent leg cramps:

• Change positions often when you're sitting or lying in bed for long periods of time.
• Drink a lot of water throughout the day to stay hydrated.
• Stretch your leg muscles before bed by bending and straightening your legs.
• Add more potassium to your diet by eating potassium-rich foods such as bananas, dried apricots, raw avocados, cantaloupe, nectarines, raisins, plain yogurt, and cooked spinach.
• Talk to your doctor about prescribing a muscle relaxant if your cramps are severe or frequent.

Tell your doctor if your leg cramps are frequent, severe, last more than 6 to 8 hours, or if your leg becomes red, swollen, or hot.