PRANTAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PRANTAL (PRANTAL).
Prantal (diphemanil methylsulfate) is a quaternary ammonium anticholinergic agent that competitively inhibits muscarinic acetylcholine receptors (M1, M2, M3 subtypes), reducing gastrointestinal motility, gastric acid secretion, and bronchial secretions. It does not cross the blood-brain barrier.
| Metabolism | Metabolized primarily by ester hydrolysis (plasma and tissue esterases) with minimal hepatic cytochrome P450 involvement. Excreted unchanged in urine and bile. |
| Excretion | Primarily renal (50-70% unchanged) with minor biliary excretion; fecal elimination accounts for approximately 10-20%. |
| Half-life | Terminal elimination half-life is 4-6 hours; steady-state achieved within 24 hours in patients with normal renal function. |
| Protein binding | Approximately 25-35%, primarily to albumin. |
| Volume of Distribution | 0.8-1.2 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is 30-60% due to first-pass metabolism. |
| Onset of Action | Oral: 30-60 minutes; intravenous: 2-5 minutes. |
| Duration of Action | 4-6 hours; may be prolonged in patients with hepatic impairment. |
| Molecular Weight | 361.9 |
50-100 mg orally 3-4 times daily; maximum 600 mg/day
| Dosage form | TABLET |
| Renal impairment | GFR 30-50 mL/min: 50 mg 3 times daily; GFR 10-29 mL/min: 50 mg twice daily; GFR <10 mL/min: 50 mg once daily |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 50% of normal dose; Child-Pugh C: avoid use |
| Pediatric use | 1-2 mg/kg/day orally divided every 6-8 hours; maximum 50 mg per dose |
| Geriatric use | Start at 25 mg 3 times daily; increase cautiously; monitor for anticholinergic effects |
| 1st trimester | Crosses placenta. Avoid during first trimester due to risk of fetal anomalies based on animal studies. |
| 2nd trimester | Use only if clearly needed. May cause adverse fetal effects. |
| 3rd trimester | Avoid near term as may cause neonatal anticholinergic effects (e.g., ileus, respiratory depression). |
Clinical note
Comprehensive clinical and safety monograph for PRANTAL (PRANTAL).
| Placental transfer | Crosses placenta; fetal concentrations may reach maternal levels. |
| Breastfeeding | Excreted into breast milk in small amounts; potential for infant anticholinergic effects including constipation, drowsiness, and decreased feeding. Monitor infant for these effects. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to propantheline or any componentNarrow-angle glaucomaObstructive uropathy (e.g., bladder neck obstruction due to prostatic hypertrophy)Obstructive disease of the gastrointestinal tract (e.g., pyloroduodenal stenosis, achalasia)Severe ulcerative colitisMyasthenia gravisToxic megacolonUnstable cardiovascular status in acute hemorrhage
| Precautions | Risk of heat prostration in hot environments due to anhidrosis; caution in glaucoma, benign prostatic hyperplasia, myasthenia gravis, hyperthyroidism, coronary artery disease, and hiatal hernia with reflux esophagitis; may impair cognitive or motor function despite limited CNS penetration; monitor for anticholinergic toxicity. |
| Food/Dietary | Avoid alcohol; may increase sedative effects. Limit caffeine and other stimulants as they may counteract anticholinergic effects. No specific food restrictions; however, high-fiber foods may worsen bloating and gas associated with GI conditions. Separate dosing from antacids by at least 1 hour. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: limited human data, animal studies show no teratogenicity at therapeutic doses. Second and third trimesters: no known fetal adverse effects, but use only if clearly needed due to anticholinergic properties potentially causing neonatal tachycardia or meconium ileus. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and urinary retention. Fetal monitoring: assess for tachycardia and meconium ileus if used near term. No specific monitoring during labor and delivery beyond standard. |
| Fertility Effects | No known negative effect on fertility based on animal studies. Anticholinergic effects may theoretically impact reproductive function due to altered secretions, but human data are lacking. |
| Clinical Pearls | PRANTAL (propantheline bromide) is a quaternary ammonium antimuscarinic used primarily for peptic ulcer disease and other GI hypermotility disorders. Due to poor CNS penetration, it has fewer central anticholinergic effects than atropine. Onset is ~30-60 min; duration 4-6 hours. Contraindicated in glaucoma, myasthenia gravis, obstructive uropathy, and GI obstruction. Use with caution in elderly due to anticholinergic side effects (constipation, urinary retention, dry mouth). |
| Patient Advice | Take this medication 30-60 minutes before meals to decrease stomach acid and cramps. · Avoid driving or operating machinery until you know how this medicine affects you; it may cause blurred vision or dizziness. · Do not use alcohol or other CNS depressants; they may worsen drowsiness. · Drink plenty of water to prevent constipation unless directed otherwise. · Avoid becoming overheated or dehydrated; this drug reduces sweating and increases heat stroke risk. · Do not take antacids or anti-diarrheal medicines within 1 hour of taking propantheline. · Notify your doctor if you experience eye pain, difficulty urinating, or severe constipation. |