Distribution
The mean volume of distribution of glycopyrrolate was estimated to be 0.42 ± 0.22 L/kg.
Metabolism
The in vivo metabolism of glycopyrrolate in humans has not been studied.
Excretion
The mean clearance and mean T1/2 values were reported to be 0.54 ± 0.14 L/kg/hr and 0.83 ± 0.13 hr, respectively post IV administration. After IV administration of a 0.2 mg radiolabeled glycopyrrolate, 85% of dose recovered was recovered in urine 48 hours postdose and some of the radioactivity was also recovered in bile. After IM administration of glycopyrrolate to adults, the mean T1/2 value is reported to be between 0.55 to 1.25 hrs. Over 80% of IM dose administered was recovered in urine and the bile as unchanged drug and half the IM dose is excreted within 3 hrs. The following table summarizes the mean and standard deviation of pharmacokinetic parameters from a study.
|
| Group | t1/2 (hr) | Vss (L/kg) | CL (L/kg/hr) | Tmax (min) | Cmax (mcg/L) | AUC (mcg/L•hr) |
| (6 mcg/kg IV)
| 0.83 ± 0.27
| 0.42 ± 0.22
| 0.54 ± 0.14
| –
| –
| 8.64 ± 1.49* |
| (8 mcg/kg IM)
| –
| –
| –
| 27.48 ± 6.12
| 3.47 ± 1.48
| 6.64 ± 2.33* |
Special Populations
Gender
Gender differences in pharmacokinetics of glycopyrrolate have not been investigated.
Renal Impairment
In one study glycopyrrolate was administered IV in uremic patients undergoing renal transplantation. The mean elimination half-life was significantly longer (46.8 minutes) than in healthy patients (18.6 minutes). The mean area-under-the-concentration-time curve (10.6 hr-mcg/L), mean plasma clearance (0.43 L/hr/kg), and mean 3-hour urine excretion (0.7%) for glycopyrrolate were also significantly different than those of controls (3.73 hr-mcg/L, 1.14 L/hr/kg, and 50%, respectively). These results suggest that the elimination of glycopyrrolate is severely impaired in patients with renal failure.
Hepatic Impairment
Pharmacokinetic information in patients with hepatic impairment is unavailable.
Pediatrics
Following IV administration (5 mcg/kg glycopyrrolate) to infants and children, the mean t1/2 values were reported to be between 21.6 and 130.0 minutes and between 19.2 and 99.2 minutes, respectively.
Teratogenic Effects
Reproduction studies with glycopyrrolate were performed in rats at a dietary dose of approximately 65 mg/kg/day (exposure was approximately 320 times the maximum recommended daily human dose of 2 mg on a mg/m2 basis) and rabbits at intramuscular doses of up to 0.5 mg/kg/day (exposure was approximately 5 times the maximum recommended daily human dose on a mg/m2 basis). These studies produced no teratogenic effects to the fetus. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Single-dose studies in humans found that very small amounts of glycopyrrolate passed the placental barrier.
Nonteratogenic Effects
Published literature suggest the following regarding the use of glycopyrrolate during pregnancy. Unlike atropine, glycopyrrolate in normal doses (0.004 mg/kg) does not appear to affect fetal heart rate or fetal heart rate variability to a significant degree. Concentrations of glycopyrrolate in umbilical venous and arterial blood and in the amniotic fluid are low after intramuscular administration to parturients. Therefore, glycopyrrolate does not appear to penetrate through the placental barrier in significant amounts. In reproduction studies in rats, dietary administration of glycopyrrolate resulted in diminished rates of pup survival in a dose-related manner.
Preanesthetic Medication
The recommended dose of glycopyrrolate injection is 0.004 mg/kg by intramuscular injection, given 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 Medication
Glycopyrrolate injection may be used during surgery to counteract drug-induced or vagal reflexes and their associated arrhythmias (e.g., bradycardia). It should be administered intravenously as single doses of 0.1 mg and repeated, as needed, at intervals of 2 to 3 minutes. The usual attempts should be made to determine the etiology of the arrhythmia, and the surgical or anesthetic manipulations necessary to correct parasympathetic imbalance should be performed.
Reversal of Neuromuscular Blockade
The recommended dose of glycopyrrolate injection is 0.2 mg for each 1.0 mg of neostigmine or 5.0 mg of pyridostigmine. In order to minimize the appearance of cardiac side effects, the drugs may be administered simultaneously by intravenous injection and may be mixed in the same syringe.
Peptic Ulcer
The usual recommended dose of glycopyrrolate injection is 0.1 mg administered at 4-hour intervals, 3 or 4 times daily intravenously or intramuscularly. Where more profound effect is required, 0.2 mg may be given. Some patients may need only a single dose, and frequency of administration should be dictated by patient response up to a maximum of four times daily.
Glycopyrrolate injection is not recommended for the treatment of peptic ulcer in pediatric patients (see PRECAUTIONS, Pediatric Use).
Preanesthetic Medication
The recommended dose of glycopyrrolate injection in pediatric patients is 0.004 mg/kg intramuscularly, given 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.
Infants
(1 month to 2 years of age) may require up to 0.009 mg/kg.
Intraoperative Medication
Because of the long duration of action of glycopyrrolate injection if used as preanesthetic medication, additional glycopyrrolate injection for anticholinergic effect intraoperatively is rarely needed; in the event it is required the recommended pediatric dose is 0.004 mg/kg intravenously, not to exceed 0.1 mg in a single dose which may be repeated, as needed, at intervals of 2 to 3 minutes. The usual attempts should be made to determine the etiology of the arrhythmia, and the surgical or anesthetic manipulations necessary to correct parasympathetic imbalance should be performed.
Reversal of Neuromuscular Blockade
The recommended pediatric dose of glycopyrrolate injection is 0.2 mg for each 1.0 mg of neostigmine or 5.0 mg of pyridostigmine. In order to minimize the appearance of cardiac side effects, the drugs may be administered simultaneously by intravenous injection and may be mixed in the same syringe.
Peptic Ulcer
Glycopyrrolate injection is not recommended for the treatment of peptic ulcer in pediatric patients (see PRECAUTIONS, Pediatric Use).