Doxylamine

Nausea and vomiting of pregnancy is a common symptom that affects the quality of life of pregnant women in the first trimester of pregnancy. In severe cases, it can lead to water and electrolyte disorders, insufficient nutritional intake, and even threaten pregnancy safety. As a first-generation antihistamine H1 receptor antagonist, doxylamine can exert sedative effects and inhibit the excitation of the vomiting center by blocking H1 receptors and 5-hydroxytryptamine receptors in the central nervous system. It is often formulated into a compound preparation with vitamin B6 for first-line treatment of hyperemesis gravidarum. It is currently an antiemetic option recommended by clinical guidelines with high safety for pregnant women and fetuses. It can also be used alone for short-term relief of allergic symptoms such as allergic rhinitis and urticaria, as well as symptomatic improvement of occasional insomnia.

The global market size of antiemetic drugs for pregnancy was approximately USD 1.27 billion in 2023, and the compound annual growth rate from 2024 to 2030 is expected to reach 5.8%, among which doxylamine-related preparations account for about 32% of the market share of antiemetic drugs for pregnancy. At present, the domestic market is still dominated by imported original research preparations, and the number of applications for local generic drugs is small. With the increasing attention of people of childbearing age to pregnancy health management and the advancement of the consistency evaluation of generic drugs, there is a large domestic substitution space in the API and preparation market of this variety. (If there is no officially released authoritative data on the segmented market size, the above data are for reference only)

The original research enterprise of doxylamine is Bausch Health (formerly Valeant Pharmaceuticals), and the original research trade name is Diclegis (compound preparation of doxylamine succinate and pyridoxine hydrochloride). Its core compound patent expired in the United States in 2015, and the compound patent in China has also expired. The main dosage form of the original research product is sustained-release tablet, with the specification of 10mg doxylamine succinate/10mg pyridoxine hydrochloride. It has been included in the FDA Reference Listed Drug Catalog, and also included in China's *Catalog of Reference Listed Drugs for Chemical Drugs*. Up to now, the doxylamine succinate APIs of several domestic enterprises have obtained CDE registration numbers and are in status A, and a number of doxylamine compound preparations have also been approved for marketing. (The data is as of June 2025, please refer to the official website of CDE for the latest information)

CATO can provide a full range of doxylamine impurity reference standards. Most products are available from stock. Stock orders paid before 16:00 can be shipped on the same day. All products meet the compliance requirements of multiple regulatory systems such as Chinese Pharmacopoeia and FDA, and can provide stable reference standard support for the whole process of API research and development, quality control and preparation application.