Comparing pyridoxine and doxylamine succinate-pyridoxine HCl for nausea and vomiting of pregnancy: A matched, controlled cohort study

J Clin Pharmacol. 2015 Jul;55(7):809-14. doi: 10.1002/jcph.480. Epub 2015 Mar 27.


Nausea and vomiting of pregnancy (NVP) is a common gestational condition. This is the first study to compare the use of vitamin B6 (pyridoxine) versus Diclectin (doxylamine succinate-pyridoxine HCl) for NVP symptoms. Participants were pregnant women with NVP who used either pyridoxine or doxylamine succinate-pyridoxine HCl for ≥4 days prior to calling the Motherisk NVP Helpline. Women receiving pyridoxine only (n = 80) were matched to a woman taking doxylamine succinate-pyridoxine HCl only (n = 80), accounting for potential confounders and baseline level of NVP, measured by the Pregnancy Unique Quantification of Emesis (PUQE) score. Change in NVP severity after a week of therapy with either pyridoxine or doxylamine succinate-pyridoxine HCl was quantified using the PUQE-24 scale, which describes NVP symptoms 24 hours prior to their call. Doxylamine succinate-pyridoxine HCl use found a significant reduction in PUQE score, compared with pyridoxine (+0.5 versus -0.2, P < .05; negative denotes worsening). This association was especially prominent in women with more severe symptoms, where doxylamine succinate-pyridoxine HCl use saw a mean improvement of 2.6 versus 0.4 with pyridoxine (P < .05). As well, doxylamine succinate-pyridoxine HCl use was associated with fewer women experiencing moderate to severe scores after a week of treatment, compared with the pyridoxine group (7 versus 17, P < .05), despite similar baseline PUQE scores.

Keywords: Diclectin; nausea; pregnancy; pyridoxine; vomiting.

Publication types

  • Comparative Study
  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Antiemetics / therapeutic use*
  • Cohort Studies
  • Dicyclomine / therapeutic use*
  • Doxylamine / therapeutic use*
  • Drug Combinations
  • Female
  • Humans
  • Morning Sickness / drug therapy*
  • Pregnancy
  • Prospective Studies
  • Pyridoxine / therapeutic use*
  • Severity of Illness Index
  • Treatment Outcome


  • Antiemetics
  • Drug Combinations
  • dicyclomine, doxylamine, pyridoxine drug combination
  • Dicyclomine
  • Doxylamine
  • Pyridoxine