Traditional Chinese medicine has for centuries touted the use of ephedra for the treatment of asthma, congestion, and bronchitis. Also known as ma huang, it predominantly consists of two alkaloids, ephedrine and pseudo-ephedrine. Ephedrine is a sympathomimetic drug, structurally similar to amphetamines. Its effects on the body include central nervous system stimulation, cardiac stimulation (ionotropic and chronotropic), bronchodilation, and elevation in blood pressure. Pseudoephedrine is an isomer of ephedrine that has weaker stimulatory effects on the central nervous system and on blood pressure (33). In the United States, ephedra has become a popular ingredient in over-the-counter weight loss preparations. It is frequently combined with herbal forms of caffeine such as guarana or kola nut.
No published studies to date exist supporting the use of either ephedra or herbal caffeine individually for weight loss. One study of combination product Metabolife-356 (containing ma huang and guarana) has shown significant effects of a combination of these two herbs on body weight, with a loss of 4.0 kg in the treatment group vs. 0.8 kg in the placebo group (p < 0.001) (34). This study was limited owing to a small sample size, short-term outcomes, and a high dropout rate, primarily secondary to cardiac side effects (e.g., palpitations, hypertension, chest pain). Additionally, Metabolife-356 contans a number of other ingredients (including chromium picolinate), whose effects on weight loss are unclear. Another study by the same principal investigator looked at the effects of a combination of ma huang and kola nut on obese individuals. In this 6-month study, significant improvement in body weight and lipid profiles was seen (35). Blood pressure changes, increased heart rate, insomnia, dry mouth, and heartburn were seen more commonly in the intervention group.
While few data are published regarding the use of herbal ephedra/ caffeine for weight loss, several studies exist that examine their proposed active ingredients (ephedrine/caffeine) (36-45). When used in combination and employed with intensive and monitored diet cointervention, ephedrine and caffeine induced short-term weight loss on the order of 3 kg over placebo in one study (40). It should be noted that no randomized, controlled, blinded trials have been extended beyond 24 weeks to support long-term efficacy or safety of either herbal or nonherbal forms of ephedrine/caffeine.
Reported side effects have included hypertension, nephrolithiasis, hepatitis, insomnia, arrythmias, myocardial infarction, and stroke. Cases of death and permanent disability have also been reported (46). Concomitant use of ephedra and other stimulant medications should be avoided to protect from potentiation of toxicity.
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