Difference between revisions of "Synephrine"

Latest revision as of 12:14, 20 September 2010

Synephrine (or oxedrine) is a drug commonly used for weight loss. While its effectiveness is widely debated, synephrine has gained significant popularity as an alternative to ephedrine, a related substance which has been made illegal or restricted in many countries due to health risks and its use as a precursor in the illicit manufacturing of methamphetamine. Products containing bitter orange or synephrine are suspected of causing adverse cardiovascular reactions ^[1]. Synephrine is derived primarily from the fruit of Citrus aurantium, a relatively small citrus tree, of which several of its more common names include Bitter Orange, Sour Orange, and Zhi shi. Dietary supplements generally supply single oral doses of 3–30 mg, while as a pharmaceutical agent it is given orally or by parenteral injection in 20–100 mg doses as a vasoconstrictor to hypotensive patients.^[2]

Claims

• Burns fat
• Increases energy
• Increases metabolism
• Promotes weight loss
• Increases body heat

Synephrine and neosynephrine

There has been some confusion surrounding synephrine and phenylephrine (neosynephrine), one of its positional isomers. The chemicals are similar in structure; the only difference is the location of the aromatic hydroxyl group. In synephrine, the hydroxyl is at the para position, whereas in neosynephrine it is at the meta position. Each compound has differing biological properties.

• Phenylephrine acts primarily on alpha₁ adrenergic receptors, so it has mainly vasoconstricting actions.
• Synephrine's pharmacology has not been thoroughly studied. Some comparisons with octopamine have been performed.^[3] There is some evidence that it may act at β₃ adrenergic receptors.^[4]

Associated risks

Many diet products such as "Stacker 2", "Xenadrine-EFX", etc. contain a "stack" of synephrine along with caffeine, sometimes with an NSAID. Some reports have indicated that such diet pills cause numerous harmful effects. The Mayo Clinic published a report that suggested a link between Stacker 2 pills and increased risk of ischemic stroke, increased blood pressure, and myocardial infarction (heart attack).

Synephrine can also cause arrhythmias ^[5]. It is similar to ephedrine ^[5] and can therefore show similar symptoms (see ephedrine adverse effects).

Following the presentation of a healthy young man with a myocardial infarction, a case study and subsequent literature review found that the makers of "nutritional supplements" who replaced ephedrine with its analogs p-synephrine and/or p-octopamine from "bitter orange" had in effect simply found a loophole in the FDA's April 2004 regulation banning ephedra in those supplements by substituting a similar substance the regulation did not address, while permitting them to label the products as "ephedra-free".^[6]

Natural occurrence

It is reported as naturally occurring in the following species: Coryphanta cornifera, C. durangensis, C. elephantides, C. greenwoodii, C. ottonis, C. pectinata, C. poselgeriana, C ramillosa, C. runyonii, Dolichothele sphaerica, D. surculosa, D. uberiformis.^[7]

References

1. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
2. ↑ Baselt RC (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, California: Biomedical Publications. pp. 1471–2. ISBN 9780962652370. 
3. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
4. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
5. ↑ ^{5.0 5.1} Livsmedelsverket (Swedish FDA)
6. ↑ Thomas JE, Munir JA, McIntyre PZ, Ferguson MA (2009). "STEMI in a 24-year-old man after use of a synephrine-containing dietary supplement : a case report and review of the literature". Tex Heart Inst J. 36 (6): 586–90. PMC 2801940 Freely accessible. PMID 20069086. CS1 maint: Multiple names: authors list (link)
7. ↑ Shulgin, Alexander & Shulgin, Ann (1997). Page 671. Tihkal: The Continuation. Berkeley: Transform Press. ISBN 0963009699 .

External links

• Ischemic Stroke Associated With Use of an Ephedra-Free Dietary Supplement Containing Synephrine (Mayo Clinic)^{[dead link]}
• Slim Pickings: Looking Beyond Ephedra (New York Times)
• SYNEPHRINE: Is Chih-shih (Zhishi) Toxic?

it:Sinefrina ja:シネフリン pl:Synefryna sv:Synefrin zh:辛弗林