Is It OK to Combine Lisinopril and Grapefruit?

The combination of lisinopril and grapefruit may be used. While grapefruit juice may interact with other medications, it has not been reported to be a problem with lisinopril. If a person is unsure about whether or not their medications are interacting, either with each other, or with foods, they should speak to their doctor or pharmacist.

Lisinopril belongs to the class of drugs called ACE-inhibitors which lower the blood pressure. They work by blocking the enzyme called the Angiotensin Converting Enzyme (ACR), which reduces the effect of angiotensin 2 and causes widening of the blood vessels, thereby lowering blood pressure. They may also decrease the work load of the heart.

All medicines are metabolized in the body and excreted through a number of different processes involving many organs and systems. Each drug undergoes metabolism in different ways and is affected by different factors. One of the systems involved in metabolism is the Cytochrome P450 enzyme system. Many drugs and some foods or drinks, such as grapefruit juice, influence this system. Some may inhibit specific enzymes in the system, while others may induce them.

If an enzyme becomes inhibited, this may result in reduced breakdown of drugs normally metabolized by that enzyme, resulting in raised levels and a possible increase in both therapeutic effect and adverse effects. Conversely, induction of an enzyme may result in a quicker breakdown of drugs normally metabolized by that enzyme, negating or lessening its required effect. Grapefruit juice is known to inhibit some of the enzymes involved in this system.

While lisinopril and grapefruit probably don't interact and can be used together, many other medications may interact with grapefruit juice due to its inhibitory action and it should be avoided by people taking them. Lisinopril and grapefruit don't fall within this group of medicines because lisinopril's metabolism does not rely on the enzymes which are blocked by grapefruit juice.

Drugs that may interact with grapefruit juice include some cholesterol drugs like statins such as atorvastatin; some calcium channel blockers, used for blood pressure and heart conditions which include felodipine and nicardipine; and some antiretroviral drugs, for people with HIV, such as saquinavir. This is by no means a full list of the medications which should not be taken with grapefruit juice. So, while there is probably no interaction between lisinopril and grapefruit, it may likely interact with other medications taken, including complementary, homeopathic and over-the counter preparations. Advice should be obtained from a doctor or pharmacist as to whether grapefruit juice should be avoided when taking some medications.