A pill routinely prescribed for morning sickness may not 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 The warning comes from researchers who conducted a new analysis of a previously unpublished trial that was used to win marketing approval for the drug in the U.S. and Canada.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 the U.S. and Diclectin in Canada. It has been taken by millions of pregnant women since it was developed in the 1970s, researchers note in PLOS One.
An older version of the medicine with an additional ingredient has been used as far back as the 1950s.
For the current study, researchers reviewed data from a decades-old trial and found little evidence that the medicine 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 the first-line treatment for nausea and vomiting during pregnancy," Persaud said by email.
"We now have more information about this 1970s study that should make us question whether this medication should have been approved and whether it was ever proven to be effective."
The original trial in the 1970s was designed to determine if the drug could alleviate morning sickness in the first trimester of pregnancy.