Mephenesin Explained

Mephenesin (INN), also called myanesin,^{[1] [2]} is a centrally acting muscle relaxant. It can be used as an antidote for strychnine poisoning. Mephenesin however presents with the major drawbacks of having a short duration of action and a much greater effect on the spinal cord than the brain, resulting in pronounced respiratory depression at clinical doses and therefore a very low therapeutic index. It is especially dangerous and potentially fatal in combination with alcohol and other depressants.^[3] Mephenesin was the inspiration for the synthesis of a derivative of 1,3-propanediol, meprobamate, by Bernard Ludwig and Frank Berger,^[4] the first tranquilizer to see widespread clinical use. Mephenesin is no longer available in North America but is used in Italy and a few other countries.^[5] Its use has largely been replaced by the related drug methocarbamol, which is better absorbed.^[6]

Mephenesin may be an NMDA receptor antagonist.^[7] Mephenesin was previously used in France as an OTC muscle relaxant called Décontractyl but was taken out of production by Sanofi Aventis and due to a French Health Ministry decree in July 2019. Mephenesin is, however, still available in Italy.

See also

• Chlorphenesin
• Guaifenesin
• Mephenoxalone
• Methocarbamol
• Prenderol

External links

• Bachmeyer C, Blum L, Fléchet M, Duriez P, Cabane J, Imbert J . [Severe contact dermatitis caused by mephenesin] . Ann Dermatol Venereol . 123 . 3 . 185–7 . 1996 . 8761781.
• Ono H, Nakamura T, Ito H, Oka J, Fukuda H . Rigidity in rats due to radio frequency decerebration and effects of chlorpromazine and mephenesin . Gen Pharmacol . 18 . 1 . 57–9 . 1987 . 3557053 . 10.1016/0306-3623(87)90170-4.

Notes and References

1. Web site: Mephenesin Definition & Meaning . Merriam-Webster Medical.
2. Berger FM . The mode of action of myanesin . British Journal of Pharmacology and Chemotherapy . 2 . 4 . 241–50 . December 1947 . 19108125 . 1509790 . 10.1111/j.1476-5381.1947.tb00341.x .
3. Web site: Mephenesin. MIMS.
4. Ban TA . The role of serendipity in drug discovery . Dialogues in Clinical Neuroscience . 8 . 3 . 335–44 . 2006 . 17117615 . 3181823 . 10.31887/DCNS.2006.8.3/tban .
5. Web site: Mephenesin. Drugs.com.
6. Huf. Ernst. Comparative Plasma Levels of Mephenesin, Mephenesin Carbamate and Methocarbamol. Proceedings of the Society for Experimental Biology and Medicine. 1959. 102. 2. 276–7. Experimental Biology & Medicine. 10.3181/00379727-102-25218. 14403806. 37483102. 8 January 2014. etal.
7. Keshavarz M, Showraki A, Emamghoreishi M . Anticonvulsant Effect of Guaifenesin against Pentylenetetrazol-Induced Seizure in Mice . Iran J Med Sci . 38 . 2 . 116–21 . 2013 . 23825891 . 3700057 .