NEW YORK (Reuters Health) – Pregnant women experiencing morning sickness may gain relief from Diclectin, a combination of doxylamine succinate and pyridoxine hydrochloride — the same components that were in Bendectin before it was withdrawn from the market 27 years ago.

The findings are reported in the American Journal of Obstetrics & Gynecology online September 16 by. They note that Diclectin is widely used in Canada.

“The main message is that there is a medication which is effective for the most common medical condition in pregnancy,” Dr. Koren told Reuters Health. “Based on the very large safety record of this agent, it should be used to alleviate morning sickness, once approved by the FDA, similar to its great benefits in Canada.”

Diclectin (Duchesnay, Inc.) is a slow-release preparation containing 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride. The authors explain that the original product, Bendectin, was voluntarily withdrawn because the costs of defending against a series of lawsuits alleging an excess of birth defects would have been prohibitive. Since then, however, many studies have confirmed the safety of this drug combination.

“The drug was studied for fetal safety in over 200,000 pregnancies,” Dr. Koren added. “No drug has been proven safe at this level, or even with 10% of this size. Add to it that two FDA committees declared it fetal safe. Lastly, this is one of very few drugs labeled as A in terms of fetal safety in the Briggs book on fetal safety.”

Dr. Koren and colleagues conducted a randomized, double-blind trial to evaluate the effectiveness of Diclectin for nausea and vomiting of pregnancy. They assigned 131 affected women to Diclectin and 125 to placebo for 14 days.

Using a validated instrument, the pregnancy-unique quantification of emesis (PUQE) score, the researcher found that symptoms improved significantly more with Diclectin than placebo. Specifically, the mean PUQE scores at baseline were 9.0 and 8.8 in the two groups, respectively, and dropped by a corresponding 4.8 and 3.9 points (p = 0.006) at 15 days.

Asked if the relatively large effect in the placebo arm was surprising, Dr. Koren replied, “Not al all. For a safe limited condition, one can expect improvement over time.” As he and his colleagues point out, participants in the study were recruited around the 9th gestational week when symptoms may have started to subside spontaneously.

After the trial ended, 64 (48.9%) of the 131 women receiving Diclectin asked to continue compassionate use of their medication, compared with 41 (32.8%) of the 125 placebo-treated women (p=0.009), according to the report.

In the current study, Diclectin was not associated with an increased risk of any adverse effects when compared with placebo, “lending further reassurance to the use of this combination by large numbers of pregnant women,” the authors write.

“American women have been orphaned from FDA-approved therapy for morning sickness for almost 30 year,” said Dr. Koren in concluding. “This is a situation that should bother every American, and especially women and their families. It may look as if women have moved forward in many areas, but for medications in pregnancy — they are in the 18th century. The system tells women: we love you, but when you are pregnant you are on your own. This study is a big step to change this situation.”

The study was supported by Duchesnay Inc., Blainville, QC, Canada.

Reference:

Effectiveness of delayed-release doxylamine and pyridoxine for nausea and vomiting of pregnancy: a randomized placebo controlled trial

Am J Obstet Gynecol 2010.