Skip to content
My WebMD Sign In, Sign Up

Weight Loss & Diet Plans

Font Size

Single Dose of Diet Pill May Cause Harm

Ephedra-Caffeine Diet Pills May Cause Immediate Spike in Blood Pressure and Heart Arrhythmias
By
WebMD Health News

Jan. 13, 2004 -- A single dose of a dietary supplement containing the recently banned ingredient ephedra and caffeine may be enough to trigger potentially deadly changes in heart rhythms.

A new study shows the popular dietary supplement Metabolife 356, which contains both ephedra and caffeine, caused almost immediate increases in blood pressure as well as changes in heart beats that could be potentially fatal.

The FDA announced a ban on the popular diet supplement ingredient ephedra, also known as Ma Huang, on Dec. 30, 2003 and warned consumers to immediately stop buying and using ephedra products.

One Dose May Be Deadly

Researchers say many people are drawn to herbal weight-loss preparations, such as those containing ephedra, because natural products are perceived as safe.

"Unfortunately, the perception of safety may be the result of a lack of data," write researcher Brian F. McBride, PharmD, of the University of Connecticut Schools of Pharmacy, and colleagues.

Questions regarding the safety of ephedra products had been raised by anecdotal cases of sudden cardiac death and stroke, but few studies have examined the safety of these products.

In the study, published in the Jan. 14 issue of the Journal of the American Medical Association, researchers looked at the effects of a single dose of Metabolife 356 containing 12 milligrams of ephedra and 40 milligrams of caffeine in 15 healthy adults. Researchers measured the participants' heart rates and blood pressure before taking the supplement or a placebo, then again one, three, and five hours afterward.

The study showed that after taking a single dose of the supplement the volunteers had higher systolic (the top number of a blood pressure reading) blood pressure (123.5 vs. 118.83 mm Hg) compared with those who took the placebo.

In addition, those who received the single dose of ephedra supplement had a longer QTc interval, which is a measured interval on an electrocardiogram. When prolonged this can lead to abnormal heart contractions.

A QTc interval of longer than 30 milliseconds has been cited as a possible cause of potentially fatal irregular heartbeats that result in sudden cardiac death. Researchers found that 53% of the participants had QTc intervals of at least 30 milliseconds while taking the dietary supplement containing ephedra and caffeine.

Researchers say that since the actual ingredients in Metabolife 356 responsible for these results are not known, people should avoid these and other similar dietary supplements until more information is known about their safety.

Today on WebMD

vegetables
Video
Woman trying clothes / dress
Assessment
 
Woman looking at reflection in mirror
Article
Hot cup of coffee
Quiz
 
woman shopping fresh produce
Video
butter curl on knife
Quiz
 
eating out healthy
Article
Smiling woman, red hair
Article
 
6-Week Challenges
Want to know more?
Chill Out and Charge Up Challenge – How to help your tribe de-stress and energize.
Spark Change Challenge - Ready for a healthy change? Get some major motivation.
I have read and agreed to WebMD's Privacy Policy.
Enter cell phone number
- -
Entering your cell phone number and pressing submit indicates you agree to receive text messages from WebMD related to this challenge. WebMD is utilizing a 3rd party vendor, CellTrust, to provide the messages. You can opt out at any time.
Standard text rates apply
thumbnail_woman_tossing_spinach
Video
lunchbox
Article
 
What Girls Need To Know About Eating Disorders
Article
teen squeezing into jeans
fitfor Teens
 

Special Sections