Medications That Should Not Be Taken With Grapefruit Juice

It is common belief that grapefruit juice contains ingredients to help prevent diseases such as atherosclerosis and decrease the risk of cancer. Many Americans drink grapefruit juice in the morning along with their medicines and this can cause a grapefruit juice-drug interaction. Some chemicals in grapefruit juice block enzymes in the gut that break down many drugs resulting in an increased level of the drugs. Depending on the medication, this increase can cause toxic side effects. Here are some medications that significantly interact with grapefruit juice.

Lovastatin (Mevacor), simvastatin (Zocor), and atorvastatin (Lipitor) are medications used to lower cholesterol. Lovastatin’s interaction, for example, with large quantities of grapefruit juice (>1 quart daily) would cause a 12-fold increase in drug concentration in the blood. Side effects of the interaction include skeletal muscle effects including muscle breakdown that can lead to acute kidney injuries. Patients are advised to switch to pravastatin, fluvastatin, or rosuvastatin, which are safer alternatives that do not interact with grapefruit juice or avoid grapefruit juice.

Midazolam (Versed) is a short-acting hypnotic. Midazolam, when taken with grapefruit juice, has been shown to have a 56% increase in blood concentration. This interaction can cause excessive drowsiness, hypotension, and a decrease in respiration rate. Flurazepam and clonazepam do not interact with grapefruit juice.

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