Glycopyrronium bromide is a medication of the muscarinic anticholinergic group. It does not cross the blood–brain barrier and consequently has no to few central effects. A synthetic quaternary amine, it is available in oral and intravenous (i.v.) forms. In anesthesia, glycopyrronium injection can be used as a preoperative medication in order to reduce salivary, tracheobronchial, and pharyngeal secretions, as well as decreasing the acidity of gastric secretion. It is also used in conjunction with neostigmine, a neuromuscular blocking reversal agent, to prevent neostigmine's muscarinic effects such as bradycardia. It is also used to reduce excessive saliva (sialorrhea). It decreases acid secretion in the stomach and so may be used for treating stomach ulcers, in combination with other medications. Glycopyrronium blocks muscarinic receptors, thus inhibiting cholinergic transmission.