Drug information of glycopyrrolate

glycopyrrolate


Glycopyrronium (as the bromide salt glycopyrrolate) is a synthetic anticholinergic agent with a quaternary ammonium structure. A muscarinic competitive antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics.

Mechanism of effect

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.

Pharmacodynamic

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

Pharmacokinetics

Onset: 1 min (IV); 15-30 min (IM, SC)

Duration: 2-3 hr (parenteral, vagal block); 7 hr (parenteral, inhibition of salivation); 8-12 hr (PO; anticholinergic effects)

Peak plasma time: 30-45 min

Incompletely absorbed from GI tract since completely ionized

Vd: 1.3-1.8 L/kg (children); 0.2-0.62 L/kg (adults)

Metabolism: Several metabolites

Excretion: Mainly as unchanged drug in feces via biliary elimination and in urine

Dosage

Usual Adult Dose for Anesthesia

Preanesthetic (reduction of secretions): 0.004 mg (0.02 mL)/kg IM 30 to 60 minutes prior to the anticipated time of induction of anesthesia or at the time the preanesthetic narcotic and/or sedative are administered.

Intraoperative: 0.1 mg (0.5 mL) IV repeated as needed every 2 to 3 minutes.

Reversal of neuromuscular blockade: 0.2 mg (1.0 mL) IV for each 1.0 mg of neostigmine or 5 mg of pyridostigmine.

Reversal of bradycardia, vagal reflexes (intraoperative): 0.1 mg IV repeated as needed at 2 to 3 minute intervals.

Usual Adult Dose for Peptic Ulcer

Parenteral: 0.1 mg (0.5 mL) IV or IM every 4 hours, 3 to 4 times daily. If a more profound effect is required the dose may be increased to 0.2 mg (1 mL).

1 mg oral tablet:
Initial dose: 1 mg orally 3 times daily or 1 mg in the morning, 1 mg in the early afternoon, and 2 mg at bedtime.
Maintenance dose: 1 mg orally twice daily to a maximum of 8 mg per day.

2 mg oral tablet: 2 mg orally 2 to 3 times daily to a maximum of 8 mg per day.

1.5 mg oral tablet: Used to provide intermediate titration doses based on patient response.

Usual Pediatric Dose for Anesthesia

Preanesthetic: 0.004 mg (0.02 mL)/kg IM 30 to 60 minutes prior to the anticipated time of induction of anesthesia or at the time the preanesthetic narcotic and/or sedative are administered. Children under 2 years of age may require up to 0.009 mg (0.45 mL)/kg.

Intraoperative: 0.004 mg (0.02 mL)/kg IV not to exceed 0.1 mg (0.5 mL) in a single dose, repeated as needed every 2 to 3 minutes.

Reversal of neuromuscular blockade: 0.4 mg (2 mL)/kg IV for each 1 mg of neostigmine or 5 mg of pyridostigmine.

Reversal of bradycardia, vagal reflexes (intraoperative): 4 mcg/kg/dose IV (maximum dose: 100 mcg/dose) at 2 to 3 minute intervals.

Usual Pediatric Dose for Excessive Salivation

3 years to 16 years with neurologic conditions associated with problem drooling:

Initiate dosing at 0.02 mg/kg orally three times daily and titrate in increments of 0.02 mg/kg every 5 to 7 days, based on therapeutic response and adverse reactions. Maximum recommended dose is 0.1 mg/kg three times daily, not to exceed 1.5 to 3 mg per dose based upon weight. Administer at least one hour before or two hours after meals.

Alerts

Use caution in patients with hepatic impairment

May cause urinary retention and further complicate existing renal impairment; dose adjustment may be necessary

Use caution in patients with hiatal hernia with reflux esophagitis

May worsen symptoms of prostatic hyperplasia and/or bladder neck destruction (may increase urinary retention); use with caution

Use caution in patients with autonomic neuropathy

Use caution in patients with hyperthyroidism

In ulcerative colitis, large doses may suppress intestinal motility and exacerbate an ileus or toxic magacolon; use is contraindicated in patients with ulcerative colitis

May decrease GI motility, which can result in constipation or intestinal pseudo-obstruction; intestinal pseudo-obstruction can result in abdominal distention, pain, nausea, or vomiting; if obstruction suspected, discontinue and evaluate

Incomplete mechanical intestinal obstruction may present as diarrhea, especially in patients with an ileostomy or colostomy; discontinue treatment if incomplete mechanical intestinal obstruction is suspected or if diarrhea occurs

May cause heat prostration in the presence of fever, high ambient temperature, physical exercise; to avoid heat postration; use caution in hot weather and/or exercise

May impair mental abilities to perform tasks that require mental alertness, including operating heavy machinery

Parenteral product contains benzyl alcohol; generally avoid in neonates

Pediatric patients with spastic paralysis may experience increased response to anticholinergics, increasing the potential for adverse effects; a paradoxical reaction characterized by hyperexcitability may occur in pediatric patients taking large doses; use caution

May increase risk for anticholinergic effects, confusion, and hallucinations; use caution

Points of recommendation

Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use this medicine in larger or smaller amounts or for longer than recommended.

You may need to take glycopyrrolate on an empty stomach, at least 1 hour before or 2 hours after a meal. Follow the instructions provided with your medicine.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup.

Store at room temperature away from moisture and heat.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.


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