THURSDAY, April 2, 2009 (HealthDay News) -- A rare set of interactions involving grapefruit juice, birth control pills and a genetic mutation almost cost a 42-year-old woman her leg, physicians report.
"It started when she was driving in the car one afternoon," said Dr. Lucinda Grande, a recent medical school graduate who is doing her residency in family medicine at the Providence Hospital of St. Peter Health Care in Olympia, the largest health-care provider in the state of Washington. "Her leg became extremely painful, from the lower back to the ankle. She didn't think much of it, but the next morning, it turned purple."
The woman was seen by Grande when she went to the hospital emergency room. She was also seen by Dr. Richard Krug, a surgeon who recognized a limb-threatening situation.
"He had an ultrasound done, which confirmed that she had a large blood clot in her leg," Grande said. "Dr. Evert-Jan Verschuyl, an interventional radiologist, did a procedure where he was able to bust up the clot."
Verschuyl injected the powerful clot-dissolving tissue plasminogen activator (tPA) into the leg, and then placed a stent to keep blood flowing through the reopened vein. It was a seemingly casual remark that the woman made as she was leaving the hospital that led to her story being published in this week's issue of The Lancet.
"She just happened to mention that she had started a diet that had her eating grapefruit for breakfast for three days," Grande said. "I wondered if that contributed to the blood clot, so I did a little bit of thinking and reading."
It's well known that grapefruit has interactions with a number of drugs, Grande said. A reference book she consulted showed that grapefruit juice magnifies the effects of the estrogen in the birth control pill the woman was taking; one effect of estrogen is to increase the likelihood of clotting. The patient was advised to stop taking the pill.
Dr. Raul Mendez, another physician involved in the case, recommended a series of follow-up tests. One of them showed that the woman had the factor V Leiden mutation, which also increases the risk of blood clots.
So it was the combination of grapefruit juice, the estrogen in the birth control pill, the clot-inducing mutation and just sitting in the car in a position that narrowed the blood vessel, that threatened amputation of the leg, Grande said.
This means there is no great lesson for people in general from the episode, she said. "Grapefruit juice is not a threat to society at large," she said. "It is very healthy in most cases. I believe this was a unique situation, and it should not discourage people from eating grapefruit."
Still, it's best for someone who intends to embark on an unusual diet, such as one that includes a lot of grapefruit, to consult a doctor about possible interactions with any medications that the person might be taking, Grande said.
"You should consult a physician about any major change in lifestyle," she said.
Its not fair to blame the grapefruit for the woman's problem, said Dr. Alan Blum, a professor of family medicine at the University of Alabama. The effects of the long auto trip she took and the oral contraceptive she was taking would be "far greater risks for a deep vein thrombosis than a total of three grapefruits over three days," Blum said.
"The bottom line is that grapefruit remains a healthful, I'd even call it essential, food for the vast majority of people," he said. "The scary message from this case report, if widely disseminated, will do far more harm than good to public health."
Interactions between grapefruit juice and medications are described by the University of Florida.