Although grapefruit juice contains various nutrients, including vitamin C, potassium, and lycopene, certain chemicals in grapefruit juice and pulp can affect the activity of enzymes in the digestive system responsible for breaking down certain medications. As a result, this often leads to abnormally high drug concentrations in the blood, causing serious side effects. Bitter grapefruit and sour oranges may also have similar effects.
The following are known drugs that can have severe reactions with grapefruit: amiodarone (used to treat and prevent arrhythmias), buspirone and sertraline (antidepressants), carbamazepine (an antiepileptic drug), cyclosporine and tacrolimus (immunosuppressants), felodipine, nifedipine, nimodipine, nisoldipine (calcium channel blockers used to treat hypertension); saquinavir (HIV medication); simvastatin, lovastatin, and atorvastatin (statins used to treat hypercholesterolemia).
If you are concerned that grapefruit juice may interfere with your medication, consult your doctor. In some cases, it is crucial to avoid grapefruit, pomelo, sour oranges, and their products, as waiting 24 hours after drinking grapefruit juice to take your medication cannot prevent interactions. In other cases, you may be able to switch to alternative medications that do not interact with these fruits.