PROPANTHELINE BROMIDE
Clinical safety rating: safe
Animal studies have demonstrated safety
Antimuscarinic; competitively blocks acetylcholine at postganglionic muscarinic receptors, inhibiting parasympathetic nerve impulses.
| Metabolism | Hepatic metabolism via ester hydrolysis; major metabolites include xanthene-9-carboxylic acid and diisopropylamine ethanol. |
| Excretion | Approximately 70% renal (tubular secretion) as metabolites and unchanged drug; 30% biliary/fecal. |
| Half-life | Terminal half-life 2.5-4 hours; clinically, dosing every 6 hours maintains therapeutic levels. |
| Protein binding | Less than 5% bound; primarily to albumin. |
| Volume of Distribution | 0.9-1.2 L/kg; indicates widespread tissue distribution. |
| Bioavailability | Oral: 10-30% due to extensive first-pass metabolism. |
| Onset of Action | Oral: 30-45 minutes; IV: 1-2 minutes. |
| Duration of Action | Oral: 4-6 hours (up to 8 hours with extended release); IV: 2-4 hours. |
| Molecular Weight | 448.4 |
15 mg orally 3 times daily before meals and 30 mg at bedtime; initial dose may be 15 mg 3 times daily.
| Dosage form | TABLET |
| Renal impairment | GFR 30-50 mL/min: reduce dose to 7.5 mg 3 times daily; GFR <30 mL/min: avoid use. |
| Liver impairment | Child-Pugh class B: reduce dose by 50%; Child-Pugh class C: avoid use. |
| Pediatric use | Infants and children: 1-2 mg/kg/day orally divided every 6-8 hours; maximum 75 mg/day. |
| Geriatric use | Initiate at 7.5 mg orally 2-3 times daily due to increased anticholinergic sensitivity; titrate cautiously. |
| 1st trimester | Avoid use unless essential; limited human data, potential anticholinergic effects. |
| 2nd trimester | Avoid use unless essential; limited human data, potential anticholinergic effects. |
| 3rd trimester | Avoid use unless essential; may cause neonatal anticholinergic symptoms (e.g., ileus, tachycardia). |
Clinical note
Other anticholinergic drugs can have additive effects Contraindicated in patients with glaucoma or severe ulcerative colitis.
| Placental transfer | Crosses placenta; extent unknown. |
| Breastfeeding | Excreted into breast milk in small amounts; avoid breastfeeding or use with caution due to potential anticholinergic effects in infant (e.g., dry mouth, constipation). |
| Lactation Rating |
■ FDA Black Box Warning
None
| Common Effects | GI spasms |
| Serious Effects |
Hypersensitivity to propantheline or any componentGlaucoma (narrow-angle)Obstructive uropathy (e.g., bladder neck obstruction due to prostatic hypertrophy)Obstructive gastrointestinal disease (e.g., pyloric stenosis)Paralytic ileusMyasthenia gravis (relative, but absolute if untreated)Tachycardia due to cardiac insufficiencySevere ulcerative colitisMegacolon
| Precautions | Use with caution in patients with autonomic neuropathy, hepatic or renal disease, hyperthyroidism, coronary artery disease, congestive heart failure, cardiac arrhythmias, hypertension, hiatal hernia, prostatic hypertrophy, and in hot or humid environments (risk of heat stroke). May cause drowsiness or blurred vision. |
| Food/Dietary |
Loading safety data…
| L3 (Moderately Safe - limited data, caution advised) |
| Teratogenic Risk | Category C. First trimester: Limited human data; animal studies show fetal resorption and delayed ossification at high doses. Second and third trimesters: No specific malformation patterns; potential for anticholinergic effects (tachycardia, decreased GI motility) in the newborn if used near term. |
| Fetal Monitoring | Monitor maternal heart rate, urinary retention, and GI motility. Fetal monitoring should include heart rate assessment during prolonged use; consider non-stress test if signs of fetal distress. |
| Fertility Effects | No direct evidence of impaired fertility in humans. Animal studies reported reduced implantation rates at high doses. Theoretical anticholinergic effects on reproductive tract secretions may alter cervical mucus. |
| Propantheline may reduce gastric emptying, potentially affecting absorption of other oral medications. Take at least 1 hour apart from other drugs. Avoid alcohol, which can exacerbate sedation and anticholinergic effects. No specific food restrictions; however, high-fiber meals may interfere with absorption if taken simultaneously. |
| Clinical Pearls | Propantheline bromide is a quaternary ammonium anticholinergic with poor CNS penetration, minimizing central side effects. Onset of action is 30-45 minutes; duration 4-6 hours. Use cautiously in patients with glaucoma, urinary retention, or myasthenia gravis. Monitor for constipation, dry mouth, and blurred vision. Avoid in patients with obstructive GI disorders or toxic megacolon. |
| Patient Advice | Take propantheline 30 minutes before meals for maximum effect on GI motility. · Avoid driving or operating heavy machinery until you know how this medication affects you, as it may cause blurred vision or dizziness. · Stay hydrated and use sugar-free gum or candy to alleviate dry mouth. · Report any difficulty urinating, eye pain, or severe constipation to your healthcare provider. · Do not take this medication if you have glaucoma, an enlarged prostate, or difficulty urinating. |