Rodent of the Week: Why did Vioxx cause heart attacks?

In 2004, the popular arthritis pain-reliever Vioxx was taken off the market because the drug unexpectedly increased the risk of heart attacks and strokes. Now researchers think they know what accounted for that risk and, perhaps, a way to get around it to create an effective, safer medication.

Using mice, the researchers found that Vioxx caused a big jump in a substance -- a fat -- that could contribute to heart attacks and strokes. The substance, called 20-hydroxyeicosatetrasanoic acid, or 20-HETE, which can constrict blood vessels in the heart and brain and increased blood clotting. The mechanism suggests that the increased risk of heart attack and stroke is not unique to Vioxx but probably is shared by all members of this class of drugs, called cox-2 inhibitors.

The research “can lead to a better medication for people suffering from acute pain,” said a co-author of the study, Bruce Hammock, a distinguished professor of entomology at the UC Davis Cancer Center. About 46 million Americans suffer from arthritis.

It’s possible, for example, that inhibiting certain enzymes could lower the amount of 20-HETE in the blood and reduce the risk of cardiovascular events.

The study was published this week in the Proceedings of the National Academy of Sciences.

-- Shari Roan / Los Angeles Times

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