ATC Group: R06AA Aminoalkyl ethers

Carbinoxamine is a histamine-H1 receptor blocking agent. It is an antihistamine with anticholinergic (drying) and sedative properties. Carbinoxamine appears to compete with histamine (type H1) for receptor sites on effector cells in the gastrointestinal tract, blood vessels and respiratory tract. Carbinoxamine is effective for the symptomatic treatment of seasonal and perennial allergic rhinitis; vasomotor rhinitis; allergic conjunctivitis due to inhalant allergens and foods; mild, uncomplicated allergic skin manifestations of urticaria and angioedema; dermatographism; as therapy for anaphylactic reactions adjunctive to epinephrine and other standard measures after the acute manifestations have been controlled.

Clemastine is an H₁-receptor antagonist. It inhibits selectively the histamine receptors of the H₁ type and reduces capillary permeability. It exerts a potent antihistaminic and antipruritic effect with a fast onset and long duration of action.

Dimenhydrinate is a theoclate salt of the ethanolamine derivative diphenhydramine. It exhibits reversible competitive antagonism with histamine for the capture of H1 receptors. It has anticholinergic (antimuscarinic) properties that explain the anti-emetic action of the drug in cases of labyrinthial irritation (nausea, vertigo), and the central suppression it causes.

Diphenhydramine is an ethanolamine-derivative antihistamine. It is an antihistamine with anticholinergic and marked sedative effects. It acts by inhibiting the effects on H₁-receptors. Diphenhydramine is effective in reducing sleep onset (i.e., time to fall asleep) and increasing the depth and quality of sleep.

Doxylamine, an ethanolamine, first-generation antihistamine crosses the blood-brain barrier and exerts an antiemetic action by selectively binding to H₁ receptors in the brain. Doxylamine is an antihistamine commonly used as a sleep aid. This drug is also used to relieve symptoms of hay fever (allergic rhinitis), hives (rash or itching), and other allergic reactions. Doxylamine is also a potent anticholinergic.

Trimethobenzamide is used for the treatment of postoperative nausea and vomiting and for nausea associated with gastroenteritis. The mechanism of action of trimethobenzamide as determined in animals is obscure, but may involve the chemoreceptor trigger zone (CTZ), an area in the medulla oblongata through which emetic impulses are conveyed to the vomiting center; direct impulses to the vomiting center apparently are not similarly inhibited.