Merck’s Menstrual Pain Study May Have Backfired

A study financed by Merck & Co. on the effectiveness of its new pill in helping ease the discomfort of menstrual pain might have backfired on the world’s largest drug company.

The study showed Merck’s pain pill Vioxx worked as well in relieving menstrual pain as the most widely ordered drug--naproxen sodium--which sells for about half the price of Vioxx.

A spokeswoman for Whitehouse Station, N.J.-based Merck said its head-to-head study comparing Vioxx against the prescription dose of naproxen sodium (sold by Roche Pharmaceuticals under the brand name Anaprox DS) was not meant to compare cost-effectiveness. It was only meant to prove Vioxx works safely, spokeswoman Mary Elizabeth Basaman said.

The Food and Drug Administration approved Vioxx in May for the treatment of osteoarthritis, acute pain in adults and treatment of menstrual pain. The drug has become one of the hottest sellers this year.

The FDA said Vioxx reduces arthritis pain with significantly less risk of stomach side effects, such as ulcers, compared with other prescription arthritis drugs as well as aspirin.

But those stomach side effects are more likely to affect people who take pain medications every day, not women who might use a drug to treat their menstrual pain a couple of days a month.

As a result, it might be difficult for Merck to claim that Vioxx is worth a premium price compared with naproxen sodium.