Drug - Food Interactions

Nutritional Values Of Grapefruit Grapefruit is a citrus fruit rich in the following nutrients: Vitamin C Vitamin A Vitamin B5 Potassium Folate Dietary Fiber

Nutritional Values Of Grapefruit The nutritional values of grapefruit varies with the color (white, pink, or red). Red and pink grapefruits have a higher amount of vitamin A. 

Medical Uses Of Grapefruit Grapefruit is an excellent source of Vitamin C which plays a role in the following: Supporting the immune system Reduce severity of cold symptoms Reduce severity of inflammatory conditions Is beneficial to promoting cardiovascular health Pink and Red Grapefruit appears to have anti-tumor activity.

Interactions Of Grapefruit With Medications What Is Interaction? It is a situation in which a substance affects the activity of the used medication by one of the following ways: The effect is increased. The effect is decreased. It produces a new effect.

How Does Grapefruit Interact When we take a medicine orally (by mouth), it has to get into our blood stream to do its action. During this a significant portion of the medicine is metabolized(changed) to inactive ingredients by a certain enzyme in either the intestine (first-pass metabolism) or the liver,decreasing the amount of medication reaching the Blood.

How Does Grapefruit Interact Grapefruit juice interferes with the enzyme system responsible for the metabolism of many medications. Therefore, the amount of medication available in the body will increase, possibly causing toxic effects.

How Long Dose Grapefruit Interaction Persist Grapefruit juice can inhibit intestinal enzyme concentration for 24 to 72 hours. Therefore, separating the times of medication administration and grapefruit consumption is not a reasonable solution. It is important to note that because of genetic differences, the extent of interaction differs from one patient to another.

Grapefruit and Statins Statins are medications that lower cholesterol levels by blocking the enzyme responsible for cholesterol synthesis in the body. Statins are the most widely prescribed cholesterol lowering medications, since they affect every aspect in the cholesterol panel in a favorable way.

Grapefruit and Statins The components in grapefruit prevent the enzyme system in the body from breaking down the statin leading to its accumulation in the body. Example: Taking one tablet of lovastatin (Mevacor) with a glass of grapefruit juice is the same as taking 12 to 15 tablets with a glass of water.

Problems Of Taking Grapefruit With Statins Problems associated with taking grapefruit with stains are: Liver damage Kidney damage Rhabdomyolisis This rare but potentially life-threatening Side effect. The most common symptoms are: Severe muscle aching throughout the entire body Muscle weakness Dark or cola-colored urine The higher the dose of statins, the higher the risk of Rhabdomyolysis.

Are All Statins Affected So far, the only statins significantly affected by this interaction are: Atorvastatin (Lipitor®) Lovastatin (Mevacor®) Simvastatin (Zocor®) Other statins do not seem to demonstrate the same, profound effect with grapefruit as seen with the other statins. These would include: Rosuvastatin (Crestor®) Pravastatin (Pravachol ®) Fluvastatin (Lescol ®) This may be due to the fact that these statins are not broken down by the same enzymes.

Grapefruit And Antihistamines Antihistamines are medications used to treat allergies. Interaction of grapefruit with antihistamines like terfenadine or astemizole leads to fatal cardiac arrhythmias (Irregular heart beat). There are other non-sedating antihistamines which do not interact with grapefruit juice. (e.g., loratidine (Claritin ®) cetirizine (Zyrtec ®).

Grapefruit and Calcium Channel Blockers Calcium Channel Blockers are medications that prevent calcium from entering cells of the heart and blood vessel walls, resulting in lowering blood pressure. Grapefruit juice is likely to increase the levels of Calcium Channel Blockers in the blood causing the following: Low blood pressure Increased heart rate Dizziness Flushing Headache

Other Medications Affected By Grapefruit Grapefruit interacts with a wide range of medications such as: Psychiatric Medications Immune Suppressants Pain Medications (Methadone) Impotence drugs Intestinal Medications (Cisapride) Grapefruit juice inhibits the body's ability to absorb some drugs like:  Losartan (for lowering blood pressure) Digoxin (for treating congestive heart failure)

Grapefruit Forms Will all forms of grapefruit cause interaction with medications It has been shown that both grapefruit sections and grapefruit extract has the same effect on medications as grapefruit juice.

Grapefruit And Citrus Fruits There are citrus fruits which can cause the same drug interaction as grapefruit such as: Seville Orange (found in marmalade and jams) Pomelos Tangelos

What Are Pomelos Pomelo - Also called the "Chinese grapefruit", it's native to southeast Asia. It is, in fact, an ancestor of the grapefruit. The grapefruit was formed from crossing between the pomelo and the orange to give us the modern grapefruit varieties we know today.

What Are Tangelos The tangelo is a hybrid between the pomelo and the tangerine. The fruit is known in some countries as "sweetie”.

Summary A number of medications are reported to have interactions with grapefruit. Before taking any medication with grapefruit you have to make sure that there is no interaction. There are several other fruit juices available as a substitute to grapefruit juice.