Grapefruit juice, birth control and other medications: Dangerous combination, or myth?

Nothing strikes fear in the hearts and minds (and loins) of people quite like a rumor that grapefruit will render birth control useless.

Just take a look at these anxious tweets about grapefruit juice interfering with the pill:

Is grapefruit juice bad news for birth control? 

In 2013, an article in the Canadian Medical Association Journal reported that eating grapefruit increased the amount of estrogen hormones absorbed into the bloodstream, Dr. Nikki B. Zite, a fellow of the American College of Obstetricians and Gynecologists, said in an email.

Here's whats going on: Large amounts of grapefruit or grapefruit juice might interfere with the way the body metabolizes estrogen, resulting in increased estrogen in the bloodstream, Zite said. She's not aware of any further research on grapefruit and hormone absorption since 2013. 

"Grapefruit juice decreases/blocks the action of the enzyme so more drug is absorbed."— Dr. Raquel Dardik

"Some medications are broken down by an enzyme (CYP3A4) in the intestine," Dr. Raquel Dardik, a gynecologist at the Joan H. Tisch Center for Women's Health at New York University Langone Medical Center, said in an email. "Grapefruit juice decreases/blocks the action of the enzyme so more drug is absorbed." 

Still, the combination is somewhat mysterious. "The clinical significance of this is not clear," Zite said, noting there was a case report of a woman who took estrogen-containing birth control and ate a grapefruit a day for three days, and then developed a blood clot. "There was also concern that an increase in estrogen exposure would increase the risk of breast cancer, but there is not a clear relationship." 

Zite noted there's no interaction between grapefruit juice and other forms of birth control like the patch, the ring, IUDs or progestin-only options, including progestin-only pills. Roughly 16% of American women aged 15 to 44 were on the pill in 2012, but injectable hormones and long-lasting reversible contraception, like IUDs, are rising in popularity, according to the Guttmacher Institute's 2015 report on contraception in the U.S.

The bottom line

You're better off avoiding the pink fruit and its acidic juice if you're on the pill, Dardik said.

"There is no data on what quantity of grapefruit juice is needed [to elicit an interaction], so the recommendation is not to take grapefruit juice while on medications, including birth control," Dardik said. 

Apart from estrogen-based birth control, other medications that can interact with grapefruit include cholesterol drugs, blood pressure drugs, anti-anxiety drugs and antihistamines, the Food and Drug Administration notes, explaining that grapefruit juice can lead to overdose (too much medication, sometimes lethal amounts, NBC News stated in 2012) or reduced doses in certain cases. 

In 2012, there were 85 medications on the market had known reactions to grapefruit, the New York Times reported then.

Your best bet when it comes to the pink juice: Ask your doctor when you begin taking a prescription medication.