What Is Grapefruit and How Does It Work?

Grapefruit is an herbal supplement which can be used in treatment to decrease deposits of plaque on artery walls (atherosclerosis), asthma, eczema, cancer, as fiber supplementation, reduction of red blood cells (hematocrit), high cholesterol, potassium supplementation, psoriasis, vitamin C supplementation, or as a weight loss aid.

There is insufficient reliable evidence as to the efficacy of grapefruit.

Grapefruit is available under the following different brand names: Citrus Paradisi, Pomelo, and Toronja.

Dosage of Grapefruit:

There is no typical dosage

More than 4 glasses juice per day for pharmacologic effects, or 1-9 glasses daily, or 240 ml of double-strength juice twice daily

Dosing Considerations – Should be Given as Follows:

  • Ventricular and Supraventricular Arrhythmias
  • Betapace or Sorine: 80 mg orally every 12 hours initially; increased as needed to 120-160 mg every 12 hours (2-3 days between increments)
  • Intravenous (substitute for oral): 75 mg over 5 hour every 12 hours initially; adjusted if necessary (on basis of monitoring of clinical efficacy, quarterly interval, and adverse effects) every 3 days; not to exceed 150 mg every 12 hours

Dosage Considerations – Should be Given as Follows:

  • None

What Are Side Effects Associated with Using Grapefruit?

Common Side effects of Grapefruit include:

  • decreased levels of red blood cells

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Grapefruit?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

  • Grapefruit has severe interactions with at least 56 different drugs.
  • Grapefruit has serious interactions with at least 52 different drugs.
  • Grapefruit has moderate interactions with at least 140 different drugs.
  • Grapefruit has mild interactions with at least 61 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.

What Are Warnings and Precautions for Grapefruit?


  • Use caution with concurrent use of CYP3A4 substrates and/or interactive agents
  • This medication contains grapefruit. Do not take Citrus Paradisi, Pomelo, or Toronja if you are allergic to grapefruit or any ingredients contained in this drug
  • In case of overdose, get medical help or contact a Poison Control Center immediately


Effects of Drug Abuse

  • None reported

Short-Term Effects

  • See "What Are Side Effects Associated with Using Grapefruit?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Grapefruit?"


  • Avoid concurrent use with CYP3AF substrates and/or interactive agents

Pregnancy and Lactation

  • Avoid excess consumption of grapefruit during pregnancy
  • Avoid excess consumption of grapefruit when breastfeeding
Medscape. Grapefruit.

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