Phenyltoloxamine

Introduction

Phenyltoloxamine is a first generation antihistamine that is used for symptoms of the common cold and as a short acting sedative. Phenyltoloxamine has not been linked to instances of clinically apparent acute liver injury.

Background

Phenyltoloxamine (fen" il tol ox' a meen) is a first generation antihistamine that is used to treat the symptoms of the common cold, including sneezing, cough, runny note, watery eyes and itching. Because of its sedating side effects, it is also used as a mild sleeping aid and sedative. Phenyltoloxamine belongs to the ethanolamine class of antihistamines (with clemastine and dimenhydrinate) and is currently used largely in combination with other agents such as phenylephrine and acetaminophen in over-the-counter products for relief of symptoms of the common cold and nighttime relief of minor aches and pains. Representative brand names of products that include phenyltoloxamine include Dologesic and Relagesic. The typical adult oral dose is 30 to 50 mg. Common side effects include sedation, impairment of motor function, confusion, dizziness, blurred vision, dry mouth and throat, palpitations, tachycardia, abdominal distress, constipation and headache. Antihistamines can worsen urinary retention and glaucoma.

Hepatotoxicity

Like most first generation antihistamines, phenyltoloxamine has not been linked to liver test abnormalities or to clinically apparent liver injury. The reason for its safety may relate its short half-life and limited duration of use.

References on the safety and potential hepatotoxicity of antihistamines are given together after the Overview section on Antihistamines.

Likelihood score: E (unlikely to be a cause of clinically apparent liver injury).

Drug Class: Antihistamines