Felodipine (Plendil) is blood pressure medication that reduces blood pressure by dilating blood vessel. Drinking 1 glass of grapefruit juice with felodipine can significantly increase felodipine concentration lasting for 3 days. Side effects that could occur from this interaction include palpitation, dizziness, a sudden drop in blood pressure, and fatigue. Verapamil and nifedipine also interact with grapefruit juice. Alternative to felodipine is amlodipine, which has less grapefruit juice-drug interaction profile. It is also advisable to stop taking grapefruit juice while patients are taking felodipine, and drink orange juice as an alternative option.
Carbamazepine is an anti-seizure medication. When carbamazepine is taken with grapefruit juice, its blood level can increase by 40%. This interaction can cause dizziness, trouble standing, drowsiness, nausea, vomiting, tremor, and feeling restlessness. Patients who are taking carbamazepine and grapefruit juice should be closely monitored and dosage should be adjusted accordingly. If the option exists, stop taking grapefruit juice while taking carbamazepine.
Viagra (sildenafil) and Levitra (vardenafil) are medications used for erectile dysfunction. Grapefruit juice interacts with these medications and boosts their levels. While this may seem as a positive aspect, it could also trigger headaches, fainting, and significantly reduce blood pressure. Avoid taking grapefruit juice while taking Viagra or Levitra, and drink orange juice as an alternative option.
Cordarone (amiodarone) is a medication used to manage irregular heart rhythm. Amiodarone when taking with Grapefruit juice can increase amiodarone blood level by 84% potentially causing serious abnormal heart beats. This is a dangerous interaction and it is important to avoid taking grapefruit juice while taking amiodarone.
Carvedilol (Coreg) is a blood pressure medication that works on the heart and blood vessel system. Consuming grapefruit juice with carvedilol can increase blood levels of a single dose of carvedilol by 16%. This can increase adverse side effect of hypotension and dizziness. It is advisable to avoid taking carvedilol with grapefruit juice or drink orange juice as an alternative.
Quinidine is a medication that is used to treat abnormal heart rhythm. Quinidine interacts with grapefruit juice, leading to decreased levels of quinidine in the blood. This could reduce the effect of quinidine. It is advisable not to take grapefruit juice when taking quinidine.