Glycopyrrolate binds competitively to the muscarinic acetylcholine receptor. Like other anticholinergic (antimuscarinic) agents, it inhibits the action of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, exocrine glands and, to a limited degree, in the autonomic ganglia. Thus, it diminishes the volume and free acidity of gastric secretions and controls excessive pharyngeal, tracheal, and bronchial secretions.
Glycopyrrolate decreases acid secretion in the stomach. Hence it can be used for treating ulcers in the stomach and small intestine, in combination with other medications. In anesthesia, glycopyrrolate injection serves as a preoperative antimuscarinic operation that reduces salivary, tracheobronchial, and pharyngeal secretions, as well as decreases the acidity of gastric secretions blocks cardiac vagal inhibitory reflexes during intubation.
Side effects include dry mouth, difficult urinating, heachaches, diarrhea and constipation. The medication also induces drowsiness or blurred vision. LD50=709 mg/kg (rat, oral).