Doxylamine, in the form of Decapryn Succinate, is an antihistamine with sedative properties. Commonly used for occasional sleeplessness, it is found in some over-the-counter sleep aids and allergy medications. Side effects may include drowsiness, dry mouth, and blurred vision.
Structure
Synthesis
Mechanism of action:
Doxylamine exerts its antihistamine effects by antagonizing H1 receptors. By blocking the action of histamine at these receptors, doxylamine helps alleviate symptoms associated with histamine release, such as those seen in allergic reactions. This antihistamine action contributes to its use in treating conditions like allergies and sleeplessness.
Properties and uses:
Doxylamine succinate is a white powder, highly soluble in water and alcohol. It is a relatively selective histamine H1-receptor antagonist. It is also an antitussive and decongestant to relieve cough and cold.
Assay:
Dissolve the sample in anhydrous acetic acid and titrate against 0.1 M perchloric acid. Determine the end-point potentiometrically.
Dose: The usual dose is 12.5 to 25 mg for adults, taken orally four to six times daily.