PHRM 221 Lecture Notes - Lecture 18: Grapefruit Juice, Surrogate Endpoint, Phenelzine
Document Summary
Even one cup of grapefruit juice can result in clinically significant and permanent inactivation of cyp3a4 enzymes in the gut drug toxicity. Note: takes 48-72 hours to replace inactivated enzymes. If a patient is starting chronic medications, examine their nutritional status. (consider patient"s nutritional status, dietary habits, or specific nutrient or supplement intake) Interaction checkers: rxfiles, canadian pharmacists" letter, uptodate, lexicomp. Management: make immediate changes to existing regimens, such as: Replace precipitant agent with alternative that lacks similar interaction (e. g. avoid combination) Make necessary dose or dosing regimen adjustments (e. g. separate doses: make no changes: Monitor the patient for s/s of possible complications due to the interaction. Long term use of drugs (rx and otc) can lead to subclinical and clinically relevant micronutrient deficiencies. May take months or years to develop. Deficiencies can be difficult to diagnose and most healthcare professionals aren"t adequately knowledgeable in this area. Result : unexplained sx may be attributed to another cause (i. e. aging, disease)
