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Weight Loss Supplement Bitter Orange (SYNEPHRINE) Linked to Stroke

Worst Pills, Best Pills Newsletter article July, 2005

The passage of the Dietary Supplement Health and Education Act (DSHEA) in 1994 opened the door for the deregulation of alternative medicines, such as dietary supplements. Under DSHEA, an endless number of alternative medicines can be sold and promoted for unsubstantiated uses without testing for safety or effectiveness. These alternative medications may be as harmful — or more so — than the products they replace.

These adverse effects of deregulation are underscored by a carefully...

The passage of the Dietary Supplement Health and Education Act (DSHEA) in 1994 opened the door for the deregulation of alternative medicines, such as dietary supplements. Under DSHEA, an endless number of alternative medicines can be sold and promoted for unsubstantiated uses without testing for safety or effectiveness. These alternative medications may be as harmful — or more so — than the products they replace.

These adverse effects of deregulation are underscored by a carefully documented case report appearing in the April 2005 Mayo Clinic Proceedings. The case involved an otherwise healthy 38-year-old man who suffered a stroke after using a weight loss dietary supplement, Stacker 2 Ephedra-Free, for one week. Stacker 2 Ephedra-Free contains the stimulant “bitter orange” (also known as synephrine) that has become the predominant replacement for the dangerous dietary supplement ephedra since it was banned in 2003.  

Synephrine is derived from the plant Citrus aurantium. It goes by a number of common names including Seville orange, green orange, sour orange, or zhi shi. Synephrine is not to be confused with the old nasal decongestant Neo-Synephrine.

Synephrine belongs to a general class of compounds known as sympathomimetic amines. As a class, sympathomimetic amines are central nervous stimulants that raise heart rate and blood pressure. More familiar members of this class include methamphetamine, or speed; dextroamphetamine (ADDERALL, DEXEDRINE); phenylpropanolamine (PPA); the dietary supplement ephedra.

Public Citizen has a long history of opposition to many members of this class of drugs. We petitioned the FDA in October 2000 to ban phenylpropanolamine in all over-the-counter (OTC) products because of the link between the use of the drug and stroke (see Worst Pills, Best Pills News December 2000). PPA was commonly found in OTC weight loss products and was also used as a nasal decongestant. The FDA banned PPA on November 6, 2000.

With the removal of PPA from the market, the dietary supplement industry rapidly geared up to replace PPA with ephedra in weight loss products, claiming it was the “natural” and safe way to lose weight. Over the years, we have written a number of articles on the dangers of ephedra-containing products. In September 2001, Public Citizen filed a formal petition with the FDA to ban the use of ephedra. We argued that the large number of deaths, heart attacks, strokes, heart arrhythmia cases, and episodes of hypertension reported to the FDA exceeded the sum for all other dietary supplements combined.

The FDA ultimately took steps to remove ephedra from the market (see Worst Pills, Best Pills News February 2004). However, by that time many producers of ephedra had stopped selling their products because of media coverage about the dangers of the supplement and because they could no longer get liability insurance.  

But even before the belated FDA ban, the dietary supplement industry was already thinking about an alternative for ephedra — synephrine, or bitter orange.

The FDA ban led the producers of several ephedra products to file suit against the agency. A federal court in Utah ruled on April 13, 2005 that the FDA’s ban on ephedra was improper. The court prohibited the FDA from taking any enforcement action against the plaintiffs in the case that would prevent them from marketing supplements containing 10 milligrams or less of ephedra per daily dose.

A drug law expert from the University of Maryland College of Pharmacy was quoted as saying that the ruling “does open the door for other manufacturers” of dietary supplements containing 10 mg of ephedrine alkaloids or less to be “marketing these products without FDA taking action against them.” On June 15, 2005, the FDA appealed the ruling of the Utah court.

The authors of the Mayo Clinic Proceedings report identified two other cases of people being harmed by synephrine that have been reported in the medical literature. The first report described an association between a heart attack and the use of a synephrine-containing dietary supplement. The second report was of an otherwise healthy young woman who experienced electrical conduction problems with her heart after taking the synephrine-containing supplement Xenadrine EFX.

We found a single review of the safety and efficacy of Citrus aurantium(synephrine) published in the November 15, 2004 issue of the American Journal of Cardiology. This review found only one randomized placebo controlled trial of sufficient quality to reanalyzed. This trial followed 20 patients for six weeks and demonstrated no statistically significant benefit for weight loss and limited information about the supplement’s safety.

DSHEA leaves the American public with an unacceptable level of risk. This law has allowed the dangerous dietary supplement synephrine to be marketed as an alternative to ephedra. Both synephrine and ephedra are chemically similar to the “speed”-like drugs, including the now-banned PPA. The legal marketing of dangerous dietary supplements will remain until DSHEA is repealed.

What You Can Do

You should not use dietary supplements containing synephrine, also known as bitter orange or Seville orange.