Bitter orange: FDA called upon to ban ephedra substitutes.(Clinical Rounds)

Rapidly proliferating "ephedra-free" weight loss supplements containing bitter orange are not a safe alternative to ephedrine-based products, experts say.

A compound present in Citrus aurantium, synephrine, is chemically similar to ephedrine and may pose the same risks--a concern that has prompted one member of Congress to call on the Food and Drug Administration to ban the supplements.

Sen. Charles E. Schumer (D-N.Y.) has sent a strongly worded letter to FDA Commissioner Mark B. McClellan requesting immediate action for the removal of these products from the market, citing urgent safety concerns.

"It took the FDA more than 8 years to go from warning people that ephedra is dangerous to actually banning it. In that time, at least 155 people died from it," Sen. Schumer said in a statement. In contrast, he said, "it took the National Football League less than 3 months to ban ephedra after the Minnesota Vikings' Korey Stringer tragically died from it at training camp."

Synephrine is an [alpha]-adrenergic agonist that, like ephedrine, can cause vasoconstriction and increase pulse rate and blood pressure.

The hazards of bitter orange go beyond the ephedra-like stimulant effects, according to Dr. Sidney Wolfe, director of Public Citizen's Health Research Group. This fruit--a centuries-old component of traditional Chinese medicine known as zhi shi--also contains compounds that interfere with drug metabolism.

Like grapefruit juice, bitter orange contains compounds that inhibit the cytochrome P450 system, through which many drugs are cleared. "This introduces a whole new set of problems aside from the stimulant effects," Dr. Wolfe told this newspaper. "We certainly would not recommend that anyone use this."