Glycopyrrolate injection for reducing secretions and managing anesthesia-related conditions

Glycopyrrolate injection is a synthetic anticholinergic medication used primarily in anesthesia to reduce secretions and block vagal reflexes. It is administered via intramuscular or intravenous injection and can also support peptic ulcer treatment in adults when oral drugs are unsuitable.

Glycopyrrolate injection is approved for the following uses in adults and pediatric patients as applicable:

• Preoperative medication: To reduce saliva, pharyngeal, tracheobronchial secretions, and gastric acidity before anesthesia induction.
• Intraoperative use: To prevent or treat bradycardia and vagal reflex arrhythmias during surgery or anesthesia.
• Reversal of neuromuscular blockade: To counteract muscarinic side effects when given with cholinesterase inhibitors like neostigmine or pyridostigmine.
• Adjunctive peptic ulcer therapy: In adults, to reduce gastric secretions when rapid effect is needed or oral therapy is not an option; not recommended as monotherapy or for pediatric peptic ulcer treatment.

Glycopyrrolate USP 0.2 mg/mL; benzyl alcohol 0.9% (as preservative)

Glycopyrrolate works by blocking acetylcholine’s action on muscarinic receptors in the autonomic nervous system, particularly in smooth muscles and exocrine glands. This reduces secretions such as saliva, bronchial mucus, and gastric acid. Unlike some anticholinergics, glycopyrrolate’s quaternary ammonium structure limits its ability to cross the blood-brain barrier, reducing central nervous system side effects.

Adults

• Preanesthetic medication: 0.004 mg/kg intramuscularly 30 to 60 minutes before anesthesia induction or with preanesthetic sedatives.
• Intraoperative use: 0.1 mg IV single doses, repeated every 2 to 3 minutes as needed to manage bradycardia or vagal arrhythmias.
• Reversal of neuromuscular blockade: 0.2 mg glycopyrrolate per 1 mg neostigmine or 5 mg pyridostigmine IV, administered simultaneously; can be mixed in the same syringe.
• Peptic ulcer (adjunctive): 0.1 mg IV or IM every 4 hours, 3–4 times daily; increase to 0.2 mg if needed; dosing frequency based on response, max four times daily.

Pediatric Patients

• Preanesthetic medication: 0.004 mg/kg IM, 30 to 60 minutes before anesthesia; infants (1 month to 2 years) may require up to 0.009 mg/kg.
• Intraoperative use: 0.004 mg/kg IV, not exceeding 0.1 mg per dose, repeated every 2 to 3 minutes if necessary.
• Reversal of neuromuscular blockade: 0.2 mg per 1 mg neostigmine or 5 mg pyridostigmine IV; simultaneous administration recommended.
• Peptic ulcer: Not recommended.

Glycopyrrolate injection contains benzyl alcohol and should not be used in neonates (under 1 month old).

• Known hypersensitivity to glycopyrrolate or any inactive ingredients.
• In peptic ulcer patients, contraindicated with glaucoma, obstructive uropathy, obstructive GI diseases, paralytic ileus, intestinal atony (especially elderly/debilitated), unstable cardiovascular status in acute hemorrhage, severe ulcerative colitis, toxic megacolon, and myasthenia gravis.

• Glaucoma: Use with great caution, if at all.
• Benzyl alcohol toxicity: Can cause serious adverse effects in neonates and preterm infants, including metabolic acidosis and 'gasping syndrome'. Consider cumulative benzyl alcohol exposure from all sources.
• CNS effects: May cause drowsiness or blurred vision; caution patients about operating machinery or driving.
• Heat prostration risk: Anticholinergic effects can reduce sweating, increasing risk during fever, hot weather, or exercise, especially in children and elderly.
• Intestinal obstruction: Early diarrhea may indicate incomplete obstruction; glycopyrrolate is inappropriate and potentially harmful in such cases.

• Common anticholinergic effects: dry mouth, urinary hesitancy/retention, blurred vision, photophobia, pupil dilation, increased eye pressure, cycloplegia, tachycardia, palpitations, decreased sweating, taste disturbances, headache, nervousness, drowsiness, weakness, dizziness, insomnia, nausea, vomiting, constipation, bloating, impotence, suppression of lactation.
• Hypersensitivity reactions: including anaphylaxis, urticaria, pruritus, dry skin.
• CNS side effects: mild confusion or excitement, especially in elderly patients.
• Serious post-marketing events: malignant hyperthermia, cardiac arrhythmias (including bradycardia, ventricular tachycardia/fibrillation), cardiac arrest, hypertension, hypotension, seizures, respiratory arrest, heart block, QTc prolongation (particularly with anticholinesterases).
• Injection site reactions: pruritus, erythema, edema, pain.

• Other anticholinergic medications (e.g., phenothiazines, antiparkinson drugs, tricyclic antidepressants) may increase antimuscarinic side effects.
• Potassium chloride in wax matrix combined with glycopyrrolate may worsen gastrointestinal lesions due to delayed transit.

Pregnancy

Glycopyrrolate is categorized as Pregnancy Category B. Animal studies show no evidence of fetal harm at exposures far above human doses, but human data are limited. The drug minimally crosses the placenta and appears not to affect fetal heart rate significantly. Use during pregnancy only if clearly needed.

Nursing Mothers

It is unknown if glycopyrrolate is excreted in human milk; caution is advised. The drug may suppress lactation.

Pediatric Use

Because of benzyl alcohol content, glycopyrrolate injection should not be used in neonates (under 1 month). Safety and efficacy in pediatric peptic ulcer treatment are not established. Some pediatric populations, including infants and children with neurologic impairment, may have increased sensitivity to anticholinergic effects. Toxicity from benzyl alcohol has been reported in neonates and low-birth-weight infants.

Overdose may cause severe anticholinergic symptoms. Treatment includes administering IV neostigmine methylsulfate in adults starting at 0.25 mg increments every 5–10 minutes (max 2.5 mg) to reverse peripheral effects. If central symptoms occur, slow IV physostigmine 0.5–2 mg can be given and repeated as needed (max 5 mg). Supportive care includes managing hypotension with fluids or pressors, symptomatic treatment of fever, and providing artificial respiration if neuromuscular blockade leads to respiratory muscle paralysis.

Store at controlled room temperature between 20°C and 25°C (68°F and 77°F).