A pill routinely prescribed for morning sickness, can be an effective nausea remedy, researchers say – although not all doctors agree.
The warning comes from researchers who conducted a new analysis of a previously published study that was used to win marketing approval for the drug in the U.S. and Canada.
The drug pyridoxine-doxylamine is sold as Diclegis in US and Diclectin in Canada. This is made by millions of pregnant women, because it was developed in the 1970s, researchers note in PLOS One. An older version of the drug with an extra ingredient has been used as far back in the 1950’s.
For the current study, the researchers looked at data from a decades-old trial, and found little evidence that the drug is effective, said study co-author Dr. Navindra Persaud, a researcher at St. Michael’s Hospital and the University of Toronto in Canada.
“This medication is recommended as first-line treatment for nausea and vomiting during pregnancy,” Persaud said by e-mail. “We now have more information about this 1970’s research that should make us question whether the medication should have been approved, and whether it has ever been proven to be effective.”
The original research in the 1970s was designed to determine if the drug can relieve morning sickness in the first trimester of pregnancy.
To see whether these results have shown that the drug is effective, Persaud and co-author Dr. Rujun Zhang of the University of Toronto examined 36,000 pages of documents from the U.S. Food and Drug Administration, including the original report of the study, the protocol and the summary of the results, and other documents from Health Canada.
About 2,300 pregnant women have participated in the original trial in 14 clinics in the U.S., the researchers found. All of the women suffer from nausea and vomiting in the first 12 weeks of pregnancy.
The women were randomly assigned to eight treatment groups, including one that received a placebo or a dummy pill, and seven that received a variety of medications, including the combination which is now sold as Diclectin.
Each participant was asked to take two tablets per day at bedtime and an additional pill in the afternoon if needed for a week.
On the basis of data of 1,599 women who completed the study, participants were 14 percent more likely to report treatment was good or excellent with Diclectin than with placebo, the new analysis found.
More about this…
Woman with a 50 percent chance of surviving cancer gives birth to quadruplets
Early boy helps dad propose mother for New Year’s wedding
Problems with the thyroid can be to blame for miscarriages, experts warn
But this finding may not be reliable because the final results of the investigation are not available, and 37 percent of the participants in the placebo group declined before the study ended, the researchers note in the current analysis.
In the new analysis, researchers also could not see how doctors scored symptoms. And, data for 30 patients recruited in the original trial were excluded from the analysis by the regulatory authorities, because data were recorded without a record of a patient visit, the new study notes.
Persaud was not able to contact one of the original researchers, and many of them have died.
Still, Persaud said that women are prescribed this medication need to stop speaking with their doctor about other options for the treatment of morning sickness.
But not all doctors agree with this assessment.
“Studies that have been done, because this process was completed in the 1970’s shows that doxylamine and pyridoxine are an effective treatment for nausea and vomiting in pregnancy,” said Dr. Siripanth Nippita, a researcher at Harvard Medical School and the Beth Israel Deaconess Medical Center in Boston, who was not involved in the current analysis.
“On the basis of a study involving more than 200,000 women, we can say that doxylamine and pyridoxine are safe to take during pregnancy,” Nippita added by e-mail. “They can be an important part of the treatment of nausea and vomiting.”