Can I drink grapefruit juice if I am taking calcium channel blockers?

Drinking grapefruit juice while taking calcium channel blockers can lead to low blood pressure, increased heart rate, dizziness, flushing and headaches.

Whether or not you can drink grapefruit juice without experiencing these effects depends very much upon you as an individual. One person might be affected in a very different way to another, even though they are on the same dose of calcium channel blockers and drinking the same amount of grapefruit juice.

The reaction depends not only on the dose and on the individual, but also on whether you are a regular, long-term grapefruit juice drinker.

As a general rule, if you have been drinking grapefruit juice regularly and have had no ill effects than it is considered safe to drink grapefruit juice. On the other hand, if you don't usually drink grapefruit juice, and suddenly develop a taste for it, it is advised that you don't start drinking it regularly.

• If you are taking diltiazem or amlodipine, you are unlikely to experience ill effects if you drink grapefruit juice.
  
• Grapefruit juice is likely to increase the levels of isradipine, lacidipine, lercanidipine, nifedipine and verapamil in your blood. If you are taking these calcium channel blockers, you may not have any ill effects. But, because there is a chance that you will, it is advised that you do not drink grapefruit juice.
  
• If you are taking felodipine, nicardipine, nimodipine, or nisoldipine you should avoid drinking grapefruit juice altogether. You should stop drinking grapefruit juice three days before therapy starts.