PAMINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PAMINE (PAMINE).
Antimuscarinic; competitively blocks acetylcholine at muscarinic receptors, reducing smooth muscle spasm and secretions.
| Metabolism | Hepatic via CYP450 enzymes (minimal data); primarily excreted unchanged in urine. |
| Excretion | Primarily renal (70-80% unchanged), with 20-30% fecal via biliary elimination. |
| Half-life | 1.5-2 hours, necessitating dosing every 4-6 hours for sustained therapeutic effect. |
| Protein binding | 25-30%, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 2-3 L/kg, indicating extensive tissue distribution beyond plasma volume. |
| Bioavailability | Oral: 10-20% due to extensive first-pass metabolism; Intravenous and intramuscular: 100%. |
| Onset of Action | Oral: 1 hour; Intravenous: 1-2 minutes; Intramuscular: 10-15 minutes. |
| Duration of Action | 4-6 hours, with shorter duration in patients with hypermotility or accelerated GI transit. |
| Molecular Weight | 320.43 |
2.5 mg orally or subcutaneously 30-60 minutes before meals and at bedtime; maximum 10 mg/day.
| Dosage form | TABLET |
| Renal impairment | No specific GFR-based guidelines; use with caution in severe renal impairment (CrCl <30 mL/min) due to reduced clearance. |
| Liver impairment | No adjustment required for Child-Pugh A or B; for Child-Pugh C, consider dose reduction by 50% due to increased bioavailability. |
| Pediatric use | 0.25-0.5 mg/kg orally 4-6 times daily; not recommended in infants <3 months. |
| Geriatric use | Initiate at 1.25 mg orally 2-3 times daily due to increased anticholinergic sensitivity and risk of confusion, falls, and urinary retention. |
| 1st trimester | Insufficient human data; animal studies show no increased risk of fetal abnormalities. Use only if clearly needed. |
| 2nd trimester | Insufficient human data; no known teratogenic effects reported. |
| 3rd trimester | May cause neonatal anticholinergic effects (e.g., tachycardia, constipation, urinary retention) if used near term. |
Clinical note
Comprehensive clinical and safety monograph for PAMINE (PAMINE).
| Placental transfer | Crosses the placenta; limited data in humans. Animal studies indicate transfer. |
| Breastfeeding | Excreted into breast milk in small amounts; unlikely to cause adverse effects in nursing infants due to low oral bioavailability. However, monitor infant for anticholinergic symptoms such as drowsiness, irritability, or gastrointestinal disturbances. |
■ FDA Black Box Warning
None.
| Serious Effects |
Narrow-angle glaucomaObstructive uropathy (e.g., bladder neck obstruction due to prostatic hypertrophy)Obstructive gastrointestinal tract disease (e.g., pyloroduodenal stenosis, achalasia)Myasthenia gravisUnstable cardiovascular status (e.g., acute myocardial infarction, severe hypertension)Hypersensitivity to methscopolamine bromide or any component
| Precautions | Heat prostration can occur in high temperature environments due to decreased sweating, May cause drowsiness or blurred vision; avoid hazardous activities, Use with caution in patients with glaucoma, prostatic hypertrophy, or gastrointestinal obstruction, Elderly patients may be more sensitive to anticholinergic effects, May exacerbate tachyarrhythmias |
| Food/Dietary | Take on empty stomach; avoid high-fat meals which may delay absorption. No specific food restrictions but alcohol may worsen CNS effects. |
Loading safety data…
| Lactation Rating |
| L2 (Probably Compatible) |
| Teratogenic Risk | Pamline (methscopolamine) is an anticholinergic agent. Animal studies have not demonstrated teratogenicity; however, no adequate well-controlled studies in pregnant women exist. First trimester: No definitive evidence of malformations, but anticholinergics may be associated with minor anomalies if used chronically. Second and third trimesters: Risk of neonatal anticholinergic effects (e.g., meconium ileus, respiratory depression) if used near term. Fetal risk cannot be excluded. Use only if clearly needed. |
| Fetal Monitoring | Monitor maternal heart rate, blood pressure, urinary retention, and signs of anticholinergic toxicity (e.g., blurred vision, dry mouth, constipation). Fetal monitoring: assess fetal heart rate and movement; consider ultrasound for growth if prolonged use. In neonates, monitor for anticholinergic effects: constipation, temperature instability, respiratory depression. |
| Fertility Effects | Anticholinergic effects may theoretically alter cervical mucus or impair implantation, but no human data specific to methscopolamine. No significant impact on spermatogenesis or oogenesis reported. No fertility studies in humans; animal studies show no adverse effects on fertility. |
| Clinical Pearls | PAMINE (methscopolamine bromide) is an anticholinergic used as adjunctive therapy for peptic ulcers and IBS. Onset is ~1 hour, duration 4-6 hours. Avoid in glaucoma, myasthenia gravis, GI obstruction, and severe ulcerative colitis. Monitor for anticholinergic toxicity, especially in elderly. Dose adjustment for renal impairment. |
| Patient Advice | Take on an empty stomach 30-60 minutes before meals. · Avoid alcohol and excessive heat; may cause decreased sweating and heat stroke. · May cause dry mouth, blurred vision, dizziness, or constipation. Report eye pain or difficulty urinating. · Do not drive or operate machinery until you know how this medication affects you. · Avoid antacids or take them at least 1 hour after this medication. |