Menthol Caffeine

Interfering acetaminophen, albuterol, aspartame, aspirin, caffeine, isoproterenol, menthol, reproterol, riboflavin, sorbitan trioleate, terbutaline, theophylline... 

A crossover study in 11 healthy subjects found that a single 100-mg dose of menthol taken with coffee containing 200 mg caffeine increased the time to maximum caffeine concentration by about 30 minutes. The increase in the actual maximum concentration was not significant, and there were no significant effects on caffeine half-life. It was thought that menthol reduced the rate of caf-... 

Gelal A, Guven H, Balkan D, Artok L, Benowitz NL. Influence of menthol on caffeine disposition and pharmacodynamics in healthy female volunteers. EurJ Clin Pharmacol (2003) 59, 417-22. 

Menthol from natural sources is obtained predominantly from the essential oil of corn mint Mentha arvensis), which is produced by steam distillation or a distdlation/extraction procedure using supercritical carbon dioxide cf. section 5.11 Caffeine). The menthol is frozen out and the crystalline mass centrifuged. Traces of impurities confer a slightly minty aroma to natural menthol. 

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