P450 isoenzymes; P450 isoforms; P450 system
The liver-mediated cytochrome P450 isoenzymes (abbreviated as CYP) constitute an enzyme family that plays a major role in drug metabolism and is the cause for some adverse drug reactions. Metabolism and clearance of a drug are presumed to be stable, allowing for basic predictions about a drug’s dose, blood levels, and pharmacological effects. Drugs are typically metabolized by a limited number of mechanisms, some of these include the P450 enzyme pathways. Drugs, foods, or herbal preparations that alter the efficiency of those pathways may also alter the plasma concentration of some drugs by inhibiting or inducing (increasing) the efficiency of a particular enzymatic pathway. There are drugs/herbs that can simultaneously induce and inhibit different isoenzymes (St. John’s Wort), or simply induce their own metabolism (carbamazepine).
Although over the counter preparations are less likely to be mentioned, some effect P450...
References and Readings
- Brunton, L. B., Lazo, J. S., & Parker, K. L. (Eds.). (2005). Goodman & Gilman’s the pharmacological basis of therapeutics (11th ed.). New York: McGraw Hill.Google Scholar
- Stahl, S. M. (2008). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications. New York: Cambridge University Press.Google Scholar