Quinine: Medicine or Mixer?

Quinine is a bitter compound that's used in tonic water but also has a long history of medical use. Can quinine prevent leg cramps? Are there side effects to drinking it? Nutrition Diva has all the details. 

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #523

Does Quinine Prevent Leg Cramps?

Quinine also gained a reputation as a treatment for Restless Legs Syndrome and nighttime leg cramps. Many physicians were prescribing Qualaquin (a quinine-based drug) to patients who suffer from leg cramps. However the FDA has issued a warning against this “off-label” use of quinine-containing medications.

In rare cases, these drugs can have serious side effects, such as severe bleeding disorders or kidney damage. Less serious side effects like digestive upset and ringing in the ears are more common.  

Malaria is a serious, sometimes life-threatening disease. For people with malaria that is not responsive to other drugs (or in cases where other drugs are not available), the benefits of quinine may outweigh the risk of side effects.  But it’s harder to justify those risks for the treatment of leg cramps, especially because there is not a lot of evidence to show that quinine is all that effective.

There is also some folk wisdom that drinking a glass of tonic water before bedtime will reduce nighttime leg cramps but this is very unlikely to have any benefit, simply because the amount of quinine that you’d get from drinking tonic water is far too small to have any pharmacological effect.

How Much Quinine Is in Tonic Water?

Just to give you some idea what we’re talking about here, the recommended dosage of Qualaquin for the treatment of malaria is about 2,000 mg per day.  The typical dose for off-label treatment of leg cramps (which the FDA does not prohibit but does recommend against) is 200 to 500 mg per day. And the amount of quinine you’d get from 8 ounces of tonic water is about 20 mg. My homemade tonic water probably contained more quinine than store-bought tonic water but still probably less than 50 mg.

Tonic water—even when homemade—is unlikely to contain enough quinine to cause any side effects...or produce any medical benefits either.

My point is that tonic watereven when homemadeis unlikely to contain enough quinine to cause any side effects. However, it doesn’t contain enough quinine to produce any medical benefits either.

There is one final thing to take into consideration and that is the amount of sugar in tonic water. Eight ounces (or a quarter liter) of tonic water contains about 20 grams of added sugars.

To give you a frame of reference, the recommended guideline for added sugars is 25 grams or lessso one little glass of tonic water uses up almost your entire allowance for the day. One advantage to the homemade stuff is that you can use a bit less syrup and reduce the sugar. You could do the same thing by diluting store-bought tonic water with plain club soda.

Thanks for your question Sherri! If you have a question or comment for me you can call the Nutrition Diva listener line at 443-961-6206.  I always love to hear from you.

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Gin and tonic drink image courtesy of Shutterstock.


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.