Induction agent of choice in bronchial asthma

Ketamine is a bronchial smooth muscle relaxant. When it is given to patients with reactive airway disease and bronchospasm, pulmonary compliance is improved. Ketamine is as effective as halothane or enflurane in preventing experimentally induced bronchospasm. The mechanism for this effect is probably a result of the sympathomimetic response to ketamine, but isolated bronchial smooth muscle studies showed that ketamine can directly antagonize the spasmogenic effects of carbachol and histamine. Because of its broncho-dilating effect, the administration of ketamine can treat status asthmaticus unresponsive to conventional therapy. A potential respiratory problem, especially in children, is the increased salivation that follows ketamine administration; this effect can be modulated by an anticholinergic drug such as atropine or glycopyrrolate. Racemic ketamine is a potent bronchodilator, making it a good induction agent for asthmatic patients; however, S(+) ketamine produces minimal bronchodilation. Ref: Miller's anesthesia 8th edition Ref: Morgan & Mikhail's clinical anesthesiology 6e