Pharmacology · Antimuscarinics (anticholinergics)
Glycopyrronium !
A quaternary antimuscarinic used in anaesthesia to dry secretions and to block the slow heart rate caused by neostigmine.
Updated 2026-11-01
Also called: Glycopyrrolate
No structure of glycopyrronium bound to its receptor exists. The figure shows N-methylscopolamine, another quaternary antimuscarinic, in the acetylcholine pocket of the human M2 receptor, the cardiac subtype through which glycopyrronium prevents bradycardia.
Mechanism of action
Glycopyrronium blocks muscarinic receptors on glands, smooth muscle and the sinus and AV nodes. It dries saliva, airway and gastric secretions and prevents vagal slowing of the heart. Its highly polar quaternary group keeps it out of the brain to a large degree, unlike atropine and scopolamine.
- Blocks muscarinic receptors on glands and the heart
- Saliva and airway secretions dry
- Vagal slowing of the heart is prevented
- Stays out of the brain (quaternary)
Pharmacokinetics
- Absorption
- Injected into a vein or muscle; oral and inhaled forms exist
- Distribution
- Limited passage across the blood-brain barrier
- Elimination
- Mostly unchanged in urine and bile; elimination is much reduced in kidney failure
- Half-life
- A little under an hour after injection
Indications
- Anaesthesia: reduce saliva and airway secretions and block vagal reflexes at induction and intubation
- With neostigmine or pyridostigmine when reversing neuromuscular block, to prevent bradycardia
- Adjunct for peptic ulcer when a rapid effect is needed (not for healing) Peptic ulcer disease →
- Severe chronic drooling in children with neurological conditions (oral solution)
Adverse effects
Common
- Dry mouth
- Urinary hesitancy and retention
- Blurred vision and light sensitivity
- Fast heart rate and palpitations
- Less sweating and constipation
Contraindications
- Hypersensitivity to glycopyrronium
- In peptic ulcer patients: glaucoma, obstructive uropathy, obstruction of the gut, paralytic ileus, unstable cardiovascular status in acute bleeding, severe ulcerative colitis or toxic megacolon, myasthenia gravis
Key interactions
- Neostigmine and pyridostigmine
- Given together on purpose: glycopyrronium blocks their muscarinic side effects
- Other anticholinergic drugs
- Additive anticholinergic effects
What is monitored
- Heart rate and rhythm
- Secretions and airway
- Urine output; kidney function before repeated use
Administration and safety
- Injected into a vein or muscle without dilution
- Compatible in the same syringe with several anaesthetic drugs, including neostigmine; for reversal both may be injected together
- Some vials contain benzyl alcohol, a concern in premature newborns
Nursing care
- Check for tachycardia before giving it
- Warn about blurred vision and drowsiness after the procedure
- Prevent overheating: avoid heat and exertion while effects last
Pregnancy and breastfeeding
Decades of use, mostly at caesarean section, have not shown a higher risk of birth defects or harm to mother or baby.
Test yourself
Think of the answer, then tap the question to see it.
Why is glycopyrronium often preferred to atropine with neostigmine?
It blocks bradycardia and secretions but, being quaternary, does not enter the brain, so it causes less confusion.
In which organ problem does glycopyrronium accumulate?
Kidney failure, since most of it is eliminated unchanged.
Can glycopyrronium heal a peptic ulcer on its own?
No. It only reduces symptoms as an adjunct; it is not a treatment for ulcer healing.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - GLYCOPYRROLATE injection (DailyMed (U.S. National Library of Medicine), 2026); Glycopyrrolate: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 11 (McGraw Hill, 2023).
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Representative model, for educational purposes only.