Mr. Squiggle!
Bluelighter
- Joined
- Aug 31, 2010
- Messages
- 354
ingesting some grapefruit?
Seems feasible:
http://www.nejm.org/doi/full/10.1056/NEJMoa041888
Although this doesn't list the exact case of grapefruit juice, but rather kidney failure:
CYP2D6 catalyzes hydroxylation or demethylation of more than 20 percent of drugs, including codeine.
O-demethylation of codeine into morphine by CYP2D6 represents a minor pathway of codeine metabolism (accounting for less than 10 percent of codeine clearance)8 but is essential for its opioid activity (Figure 1Figure 1Metabolic Pathways of Codeine Biotransformation.). N-demethylation of codeine into norcodeine by CYP3A4 and the glucuronidation of codeine are the main pathways (accounting for more than 80 percent of codeine clearance) for converting the molecule into inactive compounds.
We describe a patient who presented with life-threatening codeine intoxication despite having received only modest doses of the medication. Analysis of the patient's cytochrome P-450–dependent monooxygenase genotype (CYP2D6) and phenotype (CYP2D6 and CYP3A4) indicated that his unusual response to codeine might be explained by ultrarapid CYP2D6 metabolism, combined with the inhibition of CYP3A4 by other medications and the accumulation of active metabolites because of renal failure.
It still leads on to the question of whether or not grapefruit really does enhance the opioid activity of codeine?
Seems feasible:
http://www.nejm.org/doi/full/10.1056/NEJMoa041888
Although this doesn't list the exact case of grapefruit juice, but rather kidney failure:
CYP2D6 catalyzes hydroxylation or demethylation of more than 20 percent of drugs, including codeine.
O-demethylation of codeine into morphine by CYP2D6 represents a minor pathway of codeine metabolism (accounting for less than 10 percent of codeine clearance)8 but is essential for its opioid activity (Figure 1Figure 1Metabolic Pathways of Codeine Biotransformation.). N-demethylation of codeine into norcodeine by CYP3A4 and the glucuronidation of codeine are the main pathways (accounting for more than 80 percent of codeine clearance) for converting the molecule into inactive compounds.
We describe a patient who presented with life-threatening codeine intoxication despite having received only modest doses of the medication. Analysis of the patient's cytochrome P-450–dependent monooxygenase genotype (CYP2D6) and phenotype (CYP2D6 and CYP3A4) indicated that his unusual response to codeine might be explained by ultrarapid CYP2D6 metabolism, combined with the inhibition of CYP3A4 by other medications and the accumulation of active metabolites because of renal failure.
It still leads on to the question of whether or not grapefruit really does enhance the opioid activity of codeine?

