Glycopyrronium is an anticholinergic (antimuscarinic) drug that blocks the action of acetylcholine on muscarinic receptors in the body, thereby reducing secretions and relaxing smooth muscles. It was first developed in the 1960s and introduced into medical practice in the late 1960s to 1970s, initially for use as a pre-anesthetic medication to reduce salivary and respiratory secretions during surgery. Over time, its clinical applications expanded to include treatment of chronic obstructive pulmonary disease (COPD) in inhaled form, management of excessive sweating (hyperhidrosis), and control of drooling and secretions in palliative care. Modern inhaled formulations used for COPD were developed much later, becoming widely available in the early 2010s.
BRAND NAMES
COPD/Asthma Inhalers: Bevespi Aerosphere, Breztri Aerosphere, Seebri Breezhaler, Enerzair Breezhaler, Trixeo Aerosphere, Lonhala.
Oral/Tablets (Drooling/Ulcers): Robinul, Robinul Forte, Glycate, Dartisla ODT, Sialanar (oral solution).
Topical (Sweating): Qbrexza.
Injection (Surgery): Robinul.
MECHANISM OF ACTION
Glycopyrronium is a competitive antagonist of muscarinic (M1–M3) receptors, blocking the action of acetylcholine. This reduces parasympathetic activity, leading to decreased secretions (salivary and bronchial), bronchodilation in the airways, reduced sweating, and inhibition of smooth muscle contraction.
PHARMACOKINETICS
Absorption:
Glycopyrronium is a quaternary ammonium compound, so it is poorly absorbed from the gastrointestinal tract due to its high polarity and permanent positive charge. Oral bioavailability is very low.
Distribution:
Glycopyrronium has limited distribution in the body because it is a quaternary ammonium compound with low lipid solubility. It does not readily cross cell membranes or the blood–brain barrier, so central nervous system penetration is minimal. The volume of distribution is relatively low, and it remains largely in the extracellular fluid.
Metabolism:
A small proportion of glycopyrronium is metabolized following IV administration. The metabolic pathway for glycopyrronium is not characterized.
Elimination:
Glycopyrronium is eliminated mainly through the kidneys. A large portion of the drug is excreted unchanged in urine, while a smaller amount is eliminated via bile and feces. Its elimination half-life varies depending on the route of administration but is generally a few hours for injectable/oral forms and longer for inhaled formulations due to sustained action.
PHARMACODYNAMICS
Glycopyrronium is a potent, long-acting muscarinic antagonist (LAMA) acting as a competitive inhibitor of acetylcholine at M1-M5 receptors, with high affinity for M3/M1 receptors. It provides 24-hour bronchodilation for COPD by inhibiting bronchoconstriction, reduces secretions/arrhythmias via systemic anticholinergic effects, and topically treats hyperhidrosis, with low blood-brain barrier penetration.
ADMINISTRATION
Glycopyrronium is administered through multiple routes depending on the indication: it is given by inhalation (dry powder inhaler or nebulizer) for COPD management, orally as tablets or solution for conditions like hyperhidrosis or drooling, intravenously or intramuscularly before surgery to reduce secretions, and topically (wipes or creams) for localized excessive sweating. The route is selected based on the condition being treated and patient needs.
DOSAGE AND STRENGTH
Glycopyrronium dosage depends on the indication and route of administration. For COPD, it is commonly given as 50 mcg once daily by inhalation. In pre-anesthetic use, it is administered as 0.004 mg/kg (IV or IM). For oral use (such as hyperhidrosis or drooling), typical doses are 1–2 mg taken 2–3 times daily, adjusted according to patient response. Topical forms are usually applied once daily to the affected area.
DRUG INTERACTIONS
Glycopyrronium may interact with other medications, especially those with anticholinergic properties, leading to increased side effects like dry mouth, constipation, and urinary retention. Concomitant use with drugs such as Atropine or Ipratropium can enhance anticholinergic effects. It may also reduce the effectiveness of medications that increase gastrointestinal motility, such as Metoclopramide. Additionally, when used with certain antihistamines or tricyclic antidepressants, side effects may be intensified.
FOOD INTERACTIONS
Glycopyrronium has minimal significant food interactions. It can generally be taken with or without food. However, taking it with food may help reduce mild gastrointestinal discomfort in some patients.
CONTRAINDICATIONS
Glycopyrronium is contraindicated in patients with conditions where anticholinergic effects may worsen the disease. These include narrow-angle glaucoma, urinary retention (such as in prostatic enlargement), severe constipation or intestinal obstruction, and paralytic ileus. It should also be avoided in patients with hypersensitivity to the drug and used cautiously in those with myasthenia gravis, as it may aggravate muscle weakness.
Side Effects
Dry mouth
Constipation
Urinary retention (difficulty in passing urine)
Blurred vision
Reduced sweating (may cause heat intolerance)
OVER DOSE
Overdose of Glycopyrronium leads to severe anticholinergic toxicity such as dry mouth, blurred vision, tachycardia, fever, urinary retention, constipation, and in severe cases confusion or hallucinations.
TOXICITY
Glycopyrronium toxicity occurs due to excessive anticholinergic action, leading to symptoms like severe dry mouth, high fever, fast heart rate, urinary retention, constipation, confusion, agitation, and hallucinations. In severe cases, it may progress to seizures or coma.
