Is it true that Bitter Orange can interfere with absorption of prescription drugs?
A. There is no evidence that Bitter Orange either facilitates or reduces absorption of drugs. It has been variously speculated that Bitter Orange may either facilitate absorption of drugs (as has been shown for grapefruit), or conversely induce the Cytochrome P-450 enzyme system and increase the metabolism of drugs. There is no evidence to support either of these speculations. The well-publicized effect of grapefruit appears to be the result of a significant inhibition of gut wall cytochrome P-450 3A4 (CYP3A4) isoenzymes and P-glycoprotein (P-gp), which reduces the first-pass metabolic effect on drug absorption. This is due to substances called furanocoumarins, which have been demonstrated to inhibit the first-pass metabolism of certain drugs that are metabolized by CYP3A4. These compounds are found predominantly in the grapefruit flesh, followed by the sac, peel, and seed. They are not found in other Citrus varieties (Buslig, B. and Manthey, J.A., 2005). Furthermore, the extract of Bi
