Grapefruit and the Effect of Medication on Blood Pressure

Grapefruit, grapefruit and grapefruit juice works on the same enzyme system as St. John's work. It can lower levels of some medications in your blood or increase them. The only time I've ever seen interactions was with a patient on a blood pressure medication called Nifetipine who had gone to urgent care because they were passing out from lack of oxygen.