Doxylamine is an antihistamine commonly used in combination with pyridoxine for the treatment of nausea and vomiting during pregnancy [1].
When Did Doxylamine Patents Expire?
The original patents covering doxylamine have long expired, allowing for the generic production of the drug [2]. For instance, Unisom SleepTabs, a doxylamine succinate product, first became available in the United States in the early 1970s [3].
What About Newer Doxylamine Formulations and Brands?
While the core active ingredient is off-patent, pharmaceutical companies may have obtained patents for specific formulations, delivery methods, or new combination therapies involving doxylamine. For example, Diclegis, a prescription-strength combination of doxylamine succinate and pyridoxine hydrochloride, was approved by the FDA in 2013 and had patent protection [4]. DrugPatentWatch.com tracks patent information for many drugs, which can include brand-name medications and their associated patent exclusivity periods [5].
How Does Doxylamine Work for Morning Sickness?
Doxylamine acts as an H1 histamine receptor antagonist. Its exact mechanism in treating nausea and vomiting of pregnancy is not fully understood but is believed to involve its anticholinergic and sedative effects [1].
What are the Alternatives to Doxylamine for Morning Sickness?
Besides doxylamine, other medications used to manage nausea and vomiting in pregnancy include pyridoxine (Vitamin B6) alone, other antihistamines, and in more severe cases, different classes of antiemetics [1].
What are the Side Effects of Doxylamine?
Common side effects of doxylamine include drowsiness, dizziness, dry mouth, and constipation [1].