Q: I used to take quinine sulfate for nighttime leg cramps. I stopped because I didn't think it was really helping. What other medications do you suggest I try?

A: Unfortunately, I'm not convinced that any medication, including quinine, is effective for nighttime (nocturnal) leg cramps.

Although nighttime leg cramps are common, the cause is unknown. Besides aging, they are associated with flat feet, a sedentary lifestyle, dehydration and diabetes. Doctors tend to check electrolytes and minerals, including potassium, sodium, magnesium and calcium. However, a definite cause is rarely found.

Options for treatment include:

Stretching
Regular exercise
Drinking plenty of fluids, especially around the time of exercise
Applying heat (before or just after a cramp)
Changing footwear, including using arch supports and good cushioning

Although unproven, a number of medications are often tried:

Quinine
Muscle relaxants (such as cyclobenzaprine)
Diphenhydramine (Benadryl and many others)
Verapamil
Gabapentin

The U.S. Food and Drug Administration took action in late 2006 to limit the use of prescription quinine so that it is only used as a treatment for malaria. That's because studies suggest it does little to improve night cramps and it has some serious potential side effects, including an unstable heart rhythm, low blood counts and allergic reactions. It can also cause trouble by interacting with other medicines.

Although nocturnal leg cramps are not dangerous, they are quite painful and they disrupt sleep, so see your doctor for an evaluation. Your doctor will look for a specific cause of your leg cramps and review treatment options with you.

Q: I have restless legs, especially at night. My doctor prescribed clonazepam (Klonopin) for restless leg syndrome. It has not helped yet.

Does this medicine have to be taken for a certain amount of time before it works?

A: Restless legs syndrome is a relatively common condition marked by a bothersome urge to move the legs while resting or trying to sleep. Stretching or other movements of the legs can relieve this urge but only temporarily. People often describe the unpleasant sensation they feel in the legs as crawling, creeping or aching. These symptoms often make it quite difficult to sleep.

The cause is not known. It may be associated with other conditions such as:

Iron deficiency
Kidney disease
Diabetes
Parkinson's Disease
Pregnancy
Varicose veins
Excess caffeine intake
Stretching before bed and avoiding alcohol, nicotine and caffeine may be helpful. Yoga, homeopathy and acupuncture are of uncertain benefit.

While a number of medications may be helpful, only one is FDA-approved: ropinirole (Requip) was approved in 2005 for moderate to severe symptoms of restless leg syndrome. Other medications that may help include:

Pramipexole (a medicine that works in a similar way as ropinirole)
Clonazepam (Klonopin), triazolam (Halcion), zolpidem (Ambien) or related sedatives
Levodopa/carbidopa (Sinemet)
Gabapentin (Neurontin)
Opiods, such as codeine or propoxyphene (Darvon), though generally as an option only if other medicines have failed

Combinations of one or more of these medicines may be needed to control symptoms.

The effects of clonazepam can generally be assessed within a few days of starting the medication. If you've been taking it for a week or two without benefit, talk to your doctor about adjusting the dose or considering another treatment option.

(Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center, Boston, Mass., and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center, Boston.)