Questions Raised about Morning Sickness Drug, but Expert Group Defends Safety

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Questions raised about morning sickness drug

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TORONTO - Several Toronto-based researchers are again raising questions about a medication commonly prescribed to pregnant women for morning sickness.

In a commentary to be published Tuesday in the Journal of Obstetrics and Gynecology Canada, they point to key flaws in a study on the drug Diclectin.

The drug is a combination of an antihistamine and vitamin B6.

Lead author Dr. Nav Persaud says Canadian guidelines that recommend Diclectin for pregnant women who need medication for nausea and vomiting are based on a meta-analysis published in 1997 by researchers at Motherisk Canada, part of the Hospital for Sick Children in Toronto.

A meta-analysis is a study that gathers together and synthesizes the available clinical trial results on a drug or a treatment.

Persaud says that the 1997 meta-analysis contained errors, the result of which is that the evidence supporting Diclectin's safety is not as strong as the meta-analysis authors suggested.

The major flaw is that the drug combination was studied in far fewer women than the meta-analysis suggested, which has the effect of overstating the safety profile, he says.

A family physician and researcher, Persaud says he isn't saying the Diclectin is unsafe, only that the drug does not prevent birth defects, as the 1997 paper claimed.

He suggests the meta-analysis should not be part of the scientific literature and the Canadian treatment guidelines, which drew on the meta-analysis, should be revised.

Diclectin is a combination of doxylamine, an antihistamine, and pyridoxine, which is vitamin B6. …