A painkilling, anti-inflammatory drug may help prevent headaches in Muslims fasting from dawn to dusk for Ramazan, according to a study from Israel -- where a "Yom Kippur headache" is also known.

About four in every ten people who abstain from food and water all day during the month-long Ramazan period get headaches, said the study, published in the journal Headache.
Doctors aren't quite sure what causes them. It could be dehydration, or caffeine withdrawal in people who are used to getting their morning coffee, Drescher told Reuters Health.

Drescher and his Israel-based colleagues had already shown that Jews who took the drug known as etoricoxib, or Arcoxia, before fasting for 25 hours on the Yom Kippur holiday got fewer headaches than those who didn't.

Arcoxia, a cousin of the painkiller Vioxx, isn't approved for use in the United States because the Food and Drug Administration decided it was too similar to Vioxx, which Merck pulled from the market in 2004 when it was linked to a higher risk of heart attack. But Arcoxia is available in Israel, among other countries.

The drug has a longer-lasting effect than some other painkillers, which is important because taking a pill in the middle of the day when a headache sets in would be considered breaking the fast.

"If you take Tylenol (acetaminophen)... by the time you get around to feeling the effects of the fast, the medicine is long out of your system," Drescher said.

To see how Arcoxia would work during Ramadan, the researchers assigned 222 adults planning to fast in 2010 to either take the drug or an inactive placebo pill just before the start of fasting each day. All participants recorded how often they had a headache, and how severe it was.

After a week they switched treatments.

During the first day of fasting, when headaches are thought to be most common, 21 percent of people taking Arcoxia reported having a headache, compared to 46 percent of those who took the placebo pill.

The Arcoxia group also reported fewer total headaches during that first week, the researchers wrote. And when they did have headaches, they rated them as less severe than participants taking the placebo.