Grapefruit juice can interfere with the metabolism of a number of pharmaceutical drugs and can interfere with the metabolism to such an extent that the blood levels of the drugs go quite high. Grapefruit is known to interfere with a number of drugs that are used for prevention and treatment of cardiovascular disease. Grapefruit slices and grapefruit juice can interfere with drugs that control irregular heart rhythms.
Grapefruit juice can interfere with the metabolism of anti-diabetic agents and cause hypoglycemia.
Grapefruit juice can interfere with drugs for erectile dysfunction and cause severe dilation of the blood vessels.
Interference by grapefruit with drugs for migraine can cause gangrene or stroke.
Interference by grapefruit with some drugs for hypertension can cause a drop in blood pressure.
CONCLUSION: It is wise to check with a pharmacist if you are on a pharmaceutical medication to be sure that grapefruit juice does not interfere with its metabolism.