PATHILON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PATHILON (PATHILON).
Anticholinergic agent that competitively inhibits muscarinic acetylcholine receptors, decreasing gastrointestinal motility and gastric acid secretion.
| Metabolism | Hepatic via CYP450 enzymes (major). |
| Excretion | Primarily renal (50-70% as unchanged drug and metabolites); biliary/fecal (20-30%); minor metabolism via hepatic ester hydrolysis. |
| Half-life | Terminal elimination half-life approximately 2-4 hours; may be prolonged in elderly or patients with hepatic/renal impairment. |
| Protein binding | Approximately 90% bound primarily to albumin. |
| Volume of Distribution | Approximately 2-4 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: approximately 60-70% due to first-pass metabolism; IM: nearly 100%. |
| Onset of Action | Oral: 1-2 hours; IM: 30-60 minutes; IV: immediate (within 5 minutes). |
| Duration of Action | Oral: 4-6 hours; IM: 6-8 hours; IV: 2-4 hours; anticholinergic effects may persist longer. |
| Molecular Weight | 346.48 |
1-2 mg orally every 4-6 hours; maximum 12 mg/day. Alternatively, IM: 1-2 mg every 4-6 hours.
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: administer 50% of normal dose; GFR <10 mL/min: administer 25% of normal dose. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use or reduce dose by 75%. |
| Pediatric use | Children >2 years: 0.5-1 mg orally every 4-6 hours; maximum 6 mg/day. |
| Geriatric use | Initiate at 0.5 mg orally every 6 hours; titrate cautiously due to increased anticholinergic sensitivity and risk of cognitive impairment. |
| 1st trimester | There is no evidence of teratogenicity; however, anticholinergic effects may cause fetal tachycardia. Use only if clearly needed. |
| 2nd trimester | Limited data; risk of fetal anticholinergic effects (e.g., tachycardia, decreased GI motility). Consider risk-benefit. |
| 3rd trimester | May cause neonatal anticholinergic effects (e.g., ileus, tachycardia) if used near term. Avoid during labor. |
Clinical note
Comprehensive clinical and safety monograph for PATHILON (PATHILON).
| Placental transfer | Crosses the placenta; extent unknown. Likely due to molecular weight <500 Da. |
| Breastfeeding | Pathilon (tridihexethyl) is excreted into breast milk in small amounts. Use with caution due to potential anticholinergic effects in the infant (e.g., constipation, dry mouth, urinary retention). Monitor infant for these effects. |
■ FDA Black Box Warning
None.
| Serious Effects |
GlaucomaObstructive uropathyGastrointestinal obstructionMyasthenia gravisSevere ulcerative colitisToxic megacolon
| Precautions | May cause heat stroke due to anhidrosis, Caution in glaucoma, Caution in myasthenia gravis, Caution in gastric reflux, Caution in hepatic or renal impairment |
| Food/Dietary | No known significant food interactions. However, high-fat meals may delay absorption; take on an empty stomach for consistent effect. Avoid excessive caffeine (coffee, tea, cola) as it may counteract antispasmodic effects. Alcohol may enhance CNS depression and increase drowsiness. |
| Clinical Pearls |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Category C: Fetal risk cannot be ruled out. First trimester: Potential for teratogenic effects based on animal studies; anticholinergic drugs may cause reduced uteroplacental perfusion. Second/third trimester: Use only if clearly needed; may cause neonatal anticholinergic effects (e.g., ileus, jitteriness) if used near term. |
| Fetal Monitoring | Monitor maternal for anticholinergic side effects (dry mouth, blurred vision, tachycardia, urinary retention). Fetal monitoring: consider ultrasound for growth if used long-term; neonatal observation for anticholinergic symptoms if used near delivery. |
| Fertility Effects | Anticholinergic effects may impair fertility by altering cervical mucus viscosity and delaying gastric emptying; animal studies show no direct reproductive toxicity. |
| PATHILON (tridihexethyl chloride) is an anticholinergic/antispasmodic used for peptic ulcer disease. Use cautiously in elderly due to increased risk of confusion, urinary retention, and constipation. Avoid in patients with glaucoma, myasthenia gravis, obstructive uropathy, or GI obstruction. Onset of action is 1-2 hours, duration 4-6 hours. May cause heat stroke in hot environments due to decreased sweating. |
| Patient Advice | Take this medication exactly as prescribed, usually 30-60 minutes before meals and at bedtime. · Avoid alcohol, which can increase drowsiness and dizziness. · Do not drive or operate machinery until you know how this drug affects you; it may cause blurred vision or dizziness. · Drink plenty of fluids to prevent constipation, but avoid excessive caffeine which can worsen symptoms. · Report immediately: eye pain, difficulty urinating, severe constipation, or irregular heartbeat. · Antacids may reduce absorption; take antacids at least 2 hours apart from PATHILON. · Do not suddenly stop taking this medication without consulting your doctor. |