3. Beta-blockers

Why they're prescribed: Beta-blockers are typically prescribed to treat high blood pressure (hypertension) and arrhythmias (abnormal heart rhythms). These drugs slow the heart rate and lower blood pressure by blocking the effect of the hormone adrenaline. Beta-blockers are also used to treat angina, migraines, tremors and, in eyedrop form, certain kinds of glaucoma.

Examples: atenolol (Tenormin), carvedilol (Coreg), metoprolol (Lopressor, Toprol), propranolol (Inderal), sotalol (Betapace), timolol (Timoptic) and some other drugs whose chemical names end with "-olol."

How they can cause leg cramps: Researchers have known for more than 20 years that beta-blockers can induce leg cramps, but they haven't yet determined why. Studies have shown that beta-blockers cause the arteries in the legs and arms to narrow, which in turn causes less blood to flow through the limbs. That's why some people who take beta-blockers have cold hands and feet, a condition known as peripheral vasoconstriction. (Should you experience this side effect, it's important to let your physician know as soon as possible.) Because there's often a delay between starting on a beta-blocker and the appearance of leg cramps — anywhere from a few months to more than two years) — patients typically don't suspect a connection between the two.

Alternatives: For older people, benzothiazepine calcium channel blockers, another type of blood pressure medication, are often safer and more effective than beta-blockers.

4. Statins and fibrates

Why they're prescribed: Statins and fibrates are used to treat high cholesterol. The top-selling statins are atorvastatin (Lipitor), rosuvastatin (Crestor) and simvastatin (Zocor); the top-selling fibrate is fenofibrate (Tricor).

How they can cause leg cramps: Studies show that statins can inhibit the production of satellite cells in the muscle, interfering with muscle growth. Some researchers have also suggested that statins work, at the cellular level, to sap energy. Muscle weakness and aches throughout the body can be symptoms of statin-induced rhabdomyolysis, a breakdown of skeletal muscle that causes muscle fibers to be released into the bloodstream, sometimes harming the kidneys. Additionally, older adults who take these drugs are at greater risk of developing sarcopenia, or the wasting away of skeletal muscle and strength that's associated with aging.

Alternatives: If you're among the many millions of older Americans who don't have known heart disease but are taking these drugs to lower their slightly elevated cholesterol, ask your doctor or other health care provider about trying to lower your cholesterol by changing your diet. You also might try lowering your blood levels of homocysteine — which is linked to high cholesterol — by taking a combination of sublingual (under-the-tongue) vitamin B12 (1,000 mcg daily), folic acid (800 mcg daily) and vitamin B6 (200 mg daily).

Next page: Beta2-agonists. »