skip to Main Content

The forbidden fruit

Grapefruit contains flavonoids that can adversely react to prescription medicines.

The breakfast favourite that we all know as grapefruit was originally discovered in Barbados in 1750 by Griffith Hughes. He called it the “forbidden fruit” as he, at the time, was looking for the origin of the tree of good and evil in the Garden of Eden. It became known as grapefruit because it grows hanging in clusters, much like grapes[i].


Grapefruit is packed with a host of healthy nutrients, including potassium, vitamin C, pectin, fibre and flavonoids that are very good for us[ii]. The flavonoids contained in grapefruit do, however, interact with many prescription medications that can lead to side effects or even reduce their effectiveness. For those of you who regularly enjoy your grapefruit with breakfast, it’s important to be aware of possible interactions with the following medications.

Medication Increase effectiveness and side effects of medication Reduced effectiveness of the medication
Benzodiazepines (many sleeping tablets and tranquilisers fall into this category) Yes No
Caffeine Yes No
Calcium channel blockers for blood pressure (amlodipine, felodipine, nifedipine, nisoldipine, diltiazem) Yes No
Carbamazepine (epilepsy) Yes No
Carvedilol (blood pressure) Yes No
Amitryptyline,clomipramine (antidepressant) Yes No
Theophylline (asthma) Yes No
Propanolol (blood pressure and heart rate) Yes No
Proton pump inhibitors (heartburn and ulcers) Yes No
NSAIDS (anti-inflammatories) Yes No
SSRI antidepressants (citalopram, sertraline) Yes No
Sibutramine (appetite suppressant) Yes No
Dextromethorphan (cough suppressant) Yes No
Erythromyin (antibiotic) Yes No
Estrogens Yes No
Fexofenadine (anti-histamine) No Yes
Statins – cholesterol medicines (lovastatin, simvastatin, atorvastatin) Yes No
Methotrexate Yes No
Quinidine (heart medication) No Yes
Sildenafil (erectile dysfunction) Yes No
Warfarin Yes No


[i] Natural Standard. Grapefruit Monograph. 2011
[ii] Natural Medicines Comprehensive Database. Grapefruit Monograph. 2011

Leave a Reply

Your email address will not be published. Required fields are marked *

Back To Top