Pyridoxine/doxylamine combination products are licensed for the treatment of nausea and vomiting in pregnancy (NVP). In the UK, a delayed-release preparation is marketed as Xonvea®, in the US as Diclegis®, and in Canada as Diclectin®. Xonvea® contains the antihistamine doxylamine succinate 10mg and pyridoxine hydrochloride (vitamin B6) 10mg.
Rates of infant congenital malformation following in utero exposure to products containing this combination of drugs have been widely studied, with the majority of analyses providing no evidence of an increased risk. Data relating to other pregnancy outcomes are scarce.
Exposure to pyridoxine/doxylamine (Xonvea®) at any stage in pregnancy is not regarded as medical grounds for termination of pregnancy, nor does it require any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.