Doxylamine and pyridoxine

Severe drowsiness can occur when used in combination with alcohol or other sedating medications. ( 7 )

7.1 Drug Interactions Use of doxylamine succinate and pyridoxine hydrochloride delayed-release tablets is contraindicated in women who are taking monoamine oxidase inhibitors (MAOIs), which prolong and intensify the anticholinergic (drying) effects of antihistamines. Concurrent use of alcohol and other CNS depressants (such as hypnotic sedatives and tranquilizers) with doxylamine succinate and pyridoxine hydrochloride delayed-release tablets is not recommended.

7.2 Drug-Food Interactions A food-effect study demonstrated that the delay in the onset of action of doxylamine succinate and pyridoxine hydrochloride delayed-release tablets may be further delayed, and a reduction in absorption may occur when tablets are taken with food [see Dosage and Administration (2) , Clinical Pharmacology (12.3) ] . Therefore, doxylamine succinate and pyridoxine hydrochloride delayed-release tablets should be taken on an empty stomach with a glass of water [ see Dosage and Administration (2 )].

7.3 False Positive Urine Tests for Methadone, Opiates and PCP False positive drug screens for methadone, opiates, and PCP can occur with doxylamine succinate/pyridoxine hydrochloride use. Confirmatory tests, such as Gas Chromatography Mass Spectrometry (GC-MS), should be used to confirm the identity of the substance in the event of a positive immunoassay result.

7.1 Drug Interactions Use of doxylamine succinate and pyridoxine hydrochloride delayed-release tablets is contraindicated in women who are taking monoamine oxidase inhibitors (MAOIs), which prolong and intensify the anticholinergic (drying) effects of antihistamines. Concurrent use of alcohol and other CNS depressants (such as hypnotic sedatives and tranquilizers) with doxylamine succinate and pyridoxine hydrochloride delayed-release tablets is not recommended.

8.1 Pregnancy Risk Summary Doxylamine succinate and pyridoxine hydrochloride delayed-release tablets are intended for the treatment of nausea and vomiting of pregnancy in women who do not respond to conservative management. Maternal risks are discussed throughout the labeling. No increased risk for congenital malformations has been reported in epidemiologic studies in pregnant women. In the U.S. general population, the estimated background risks for major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively.

Data ​Human Data The combination of doxylamine succinate and pyridoxine hydrochloride has been the subject of many epidemiological studies (cohort, case control and meta-analyses) designed to detect possible teratogenicity. A meta-analysis of 16 cohort and 11 case-control studies published between 1963 and 1991 reported no increased risk for malformations from first trimester exposures to doxylamine succinate and pyridoxine hydrochloride, with or without dicyclomine hydrochloride.

A second meta-analysis of 12 cohort and 5 case-control studies published between 1963 and 1985 reported no statistically significant relationships between fetal abnormalities and the first trimester use of the combination doxylamine succinate and pyridoxine hydrochloride with or without dicyclomine hydrochloride.