Levaquin and Grapefruit

Levaquin is an antibiotic prescribed to treat kidney infections, sinus infections, skin infections, urinary tract infections and pneumonia. It also used to treat bronchitis, endocarditis, tuberculosis and some sexually transmitted diseases, and it prevents anthrax infections among people exposed to the sometimes deadly bacteria. Grapefruit reacts adversely with a long list of medications, but Levaquin is not among them, as of August 2011.

No Known Interaction

Neither MedlinePlus nor the Food and Drug Administration lists grapefruit as a substance to avoid while taking Levaquin. The most recent FDA label for Levaquin was approved in June 2011 and did not list any possible interactions between Levaquin and grapefruit. According to the People's Pharmacy, however, most drugs have not been tested for an interaction with grapefruit. Therefore, just because a reaction between a certain medication and grapefruit isn't known to exist does not mean that a reaction couldn't occur.

CYP34A Enzyme and Grapefruit

Grapefruit can become a problem with drugs that are metabolized primarily by the CYP34A enzyme. Grapefruit prevents this enzyme from metabolizing drugs. If eat grapefruit or drink grapefruit juice while taking a medication meant to be metabolized by your CYP34A enzyme, the drug will take longer than usual to exit your system. If you take the medication on a daily basis, you may end up with an excess of the drug in your system, creating an overdose. Known side effects of combining grapefruit with some medications include blood clots, strokes and heart attacks.

Limited Metabolizing

Levaquin exits your body without being metabolized. It leaves your body, secreted through urine, practically unchanged, according to the FDA. Since Levaquin isn't meant to be metabolized, grapefruit's effect on metabolism shouldn't elevate the amount of it in your bloodstream. Grapefruit should not boost the effects or side effects of Levaquin. But Levaquin is a powerful drug that may produce serious side effects on its own. Some, including difficulty breathing or a snapped tendon, require immediate medical care. Be sure to discuss side effects of Levaquin with your doctor. Also let your doctor know about any herbs, supplements or medications you take, as they may interact with Levaquin. And to be on the safe side, also ask your doctor about consuming grapefruit while taking Levaquin.

Drugs Affected by Grapefruit

Unlike Levaquin, many drugs are designed to be metabolized by your CYP34A enzyme. If grapefruit prevents this process from occurring, adverse effects may result. Some medications known to react adversely with grapefruit include calcium channel blockers, antidepressants, statins, oral contraceptives, anti-anxiety medications, sleeping drugs and immunosuppressants, among others. Before taking medication with grapefruit, first ask your doctor or pharmacist about any possible adverse interactions.