The US Food and Drug Administration (FDA) has long been wary of products intended to treat "morning sickness"-vomiting and nausea-in pregnant women. In the late 1950s and early '60s, FDA narrowly avoided approving Thalidomide, a morning sickness drug later found to cause horrible birth defects to children. A similar drug, Bendectin (doxylamine succinate/pyridozine hydrochloride), was pulled off the market in 1983 by its then-manufacturer, Merrell Dow, after being accused of also causing birth defects. Now that same product is back on the market, approved by FDA under the brand name Diclegis.
The product's new manufacturer, Duchesnay USA, explained in a statement that its studies had not shown any increased risks to unborn children.
"The FDA granted Diclegis Pregnancy Category A status, which means the results of controlled studies have not shown an increased risk to an unborn baby during pregnancy," the company wrote. "The two active ingredients in Diclegis that reduce nausea and vomiting in pregnancy - doxylamine succinate and pyridoxine hydrochloride, or vitamin B6, - have been recommended as a first-line pharmacotherapy by the American Congress of Obstetricians and Gynecologists (ACOG) guidelines for the last nine years."
The therapeutic category's storied and infamous past may impart a stigma on the product, but it also confers at least one major advantage for Duchesnay: It is the only FDA-approved treatment for morning sickness, otherwise known as nausea and vomiting of pregnancy (NVP).
"The FDA approval of Diclegis provides an important new treatment to the millions of women suffering from nausea and vomiting of pregnancy, and fills a 30-year void in the treatment of NVP," said Gilbert Godin, CEO of Duchesnay. "Duchesnay USA is honored to bring the only FDA-approved treatment to help control symptoms of morning sickness to market."
Notable Lack of Safety Concerns
FDA's approval statement adds some additional context to the approval, noting that it was approved based on placebo-controlled studies of 261 women over the age of 18 who had already been pregnant for 7-14 weeks.
"The study results showed that women taking Diclegis experienced greater improvement in nausea and vomiting than those taking placebo," FDA wrote. "Additionally, observational (epidemiological) studies have shown that the combination of active ingredients in Diclegis does not pose an increased risk of harm to the fetus."
FDA's concerns on the matter seem to have been entirely placated. While the agency could have required additional postmarketing studies or even a Risk Evaluation and Mitigation Strategies (REMS) plan to account for unknown risk, neither is mentioned in the drug's approval notice. Duchesnay's press release does not mention any postmarketing obligations, black box warnings or other REMS elements.