Cialis and Grapefruit

by on July 10, 2012

Although grapefruit is an excellent source of vitamin C, eating grapefruit and grapefruit products while taking certain medications can cause certain side effects and interactions. Cialis (tadalafil), a prescription medication used to treat erectile dysfunction, is among the many medications that are known to interact with grapefruit. If you are using Cialis and want to consume grapefruit products, be sure to discuss it first with your healthcare provider. Drinking grapefruit juice can reduce the pharmacologic effects of the drug and could even stop you from achieving an erection.

Grapefruit contains substances that are known to interact with the enzyme CYP3A4 which is found in the intestine and liver. This enzyme is responsible for the metabolism of certain medications, including Cialis.  When you take medication, the body produces CYP3A4 and immediately breaks down the substance, releasing it slowly and allowing it to work at an expected rate. However, eating grapefruit can significantly reduce the amount of CYP3A4, causing decreased metabolism of this medication.  This means that the Cialis stays in the body much longer than expected.

Possible Side Effects

Eating grapefruit while taking Cialis can increase the risk of side effects that include:

  • Dizziness
  • Drowsiness
  • Headache
  • Nausea
  • Stomach upset

In severe cases, the decreased break down of Cialis can lead to increased drug levels in the blood which could potentially cause an overdose. As with any other drug, an overdose can be extremely dangerous and can even be life-threatening. If not properly treated, an overdose can lead to heart problems, strokes, and even brain damage.

Take note that even if you use Cialis only on an “as need” basis, consuming grapefruit can still cause harm to you. The components of grapefruit juice can stay in the digestive system for up to 72 hours. If you consume at least a glass of grapefruit juice, you should wait for at least three days before you can take Cialis. It is possible for you to experience side effects if you take Cialis within 72 hours of eating grapefruit or drinking grapefruit juice. To avoid possible side effects, it is best to avoid all products that contain grapefruit altogether.

If you decide to drink grapefruit while taking Cialis, be sure to watch out for possible side effects. In case of disturbing side effects, contact your healthcare provider right away.