Pyridoxine/doxylamine, sold under the brand name Diclectin among others, is a combination of pyridoxine hydrochloride (vitamin B6) and doxylamine succinate. It is generally used for nausea and vomiting of pregnancy (morning sickness); even though its efficacy has not been proven and subsequent research has led to the removal of recommendations in medical journals. Medical uses The combination of pyridoxine, commonly referred to as vitamin B6 and doxylamine may be an effective for the management of nausea and vomiting of pregnancy, but it is only recommended for use in a small number of cases after lifestyle, diet and vitamin B6. A 2018 review found the benefit was small. Doxylamine and pyridoxine are pregnancy compatible drugs, consistent with FDA's safety assessment of the combination product. They have been categorized by the FDA as a category A drug (no evidence of risk to the fetus). This letter classification system for risk in pregnancy is no longer being utilized and is currently being phased out by the FDA. Medical organizations’ position The American Congress of Obstetricians and Gynecologists (ACOG) states "Safe and effective treatments are available for more severe cases, and mild cases of nausea and vomiting of pregnancy may be resolved with lifestyle and dietary changes." The American Family Medicine recommends, "Initial treatment is conservative and includes dietary changes, emotional support, and vitamin B6 supplementation." This treatment has a Grade A, "consistent, good-quality patient-oriented evidence " while the addition of prescribing doxylamine has a Grade C, "consensus, disease-oriented evidence, usual practice, expert opinion, or case series." Canadian Family Physician issued a correction stating previous articles which stated Diclectin should be used as a first line therapy were incorrect, based upon undisclosed conflicts of interest with the manufacturer, and not peer reviewed studies:"Recommendations in 2 articles published in Canadian Family Physician, “Nausea and vomiting of pregnancy. Evidence-based treatment algorithm” and “Treatment of nausea and vomiting in pregnancy. An updated algorithm,” have subsequently come under critical scrutiny. These articles were not subjected to standard peer review, and Canadian Family Physician acknowledges that upon closer inspection these articles did not provide satisfactory evidence that would have justified the recommendation of doxylamine-pyridoxine as a sole first-line treatment for nausea and vomiting in pregnancy (NVP). More recent Canadian NVP guidelines have been published; however, a subsequent re-analysis questions the conclusions of 1 of the studies cited in these guidelines to justify doxylamine-pyridoxine as a recommended first-line treatment for