GRAPEFRUIT JUICE – DRUG INTERACTIONS
W. G. Franklin, M.D.
- Grapefruit juice (GFJ) has flavonoids and other compounds
- These help prevent arteriosclerosis and breast cancer
- GFJ reduces liver and intestinal breakdown of certain medicines
- Consequent build-up of cyclosporine (transplant reject medication) may have adverse affects
- Build up of Lipitor (atorvastatin), Mevacor (lovastatin), or Zocor (simvastatin) may be disadvantageous if liver tests rise above normal
- Could reduce dosage for desired effect on cholesterol
- No interaction with Pravactiol (pravastatin) reported yet
- Build up of calcium channel blockers such as Plendil (felodipine), Norvasc (amlodipine) and Procardia (nifedipine) may increase blood pressure reduction
- No effect on Cardizem (diltiazem) or Calan (verapamil)
- Questionable affect on Viagra (sildenafil) increasing potency
Recommendations:
- Take medication at different time of day than drinking GFJ
· e.g. drink GFJ at breakfast, take once daily medication at noon or 6 p.m.
- Consult with your physician regarding potential interactions
· there are multiple other medications such as Valium (diazepam) and Buspar (buspirone) which may have their levels increased
- Remember dietary concerns
· GFJ is 100 calories per 8 oz.
· Drinking 3 glasses a day (300 calories) would require the average person to walk for 1.5 hours to burn this up
· Whatever is not burned up in a day is stored, mostly as fat
o Fat is then used by the liver to make cholesterol
Literature Cited
Kane, Garvan, et al. Drug-grapefruit juice interactions. Mayo Clin. Prec. 2000; 75:933-942.