Comparative Pharmacology
Head-to-head clinical analysis: LOMOTIL versus LONOX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LOMOTIL versus LONOX.
LOMOTIL vs LONOX
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Diphenoxylate is a meperidine congener that acts as an opioid receptor agonist, inhibiting gastrointestinal motility and prolonging transit time; atropine is added to discourage abuse at high doses.
Loperamide is an opioid receptor agonist that acts on mu-opioid receptors in the myenteric plexus of the large intestine, inhibiting peristalsis and prolonging transit time. It also reduces colonic water and electrolyte secretion, enhancing fluid and electrolyte absorption. Loperamide has low systemic bioavailability due to extensive first-pass metabolism and is not significantly absorbed into the central nervous system due to P-glycoprotein efflux transport.
Adults: 2 tablets (2.5 mg diphenoxylate/0.025 mg atropine) orally four times daily until control of diarrhea is achieved; maintenance dose is 2 tablets once or twice daily. Maximum dose: 8 tablets (20 mg diphenoxylate) per day.
1-2 mg orally every 6 hours as needed for diarrhea; maximum 8 mg per day.
None Documented
None Documented
Diphenoxylate: 2.5-3.5 hours; Difenoxin (active metabolite): 12-24 hours. Clinically, antidiarrheal effect is prolonged due to metabolite accumulation.
Terminal half-life 12-15 hours; prolonged (up to 30 h) in elderly and renal impairment.
Primarily renal (50-70% as metabolites, <5% unchanged) and fecal (30-50% via biliary excretion).
Primarily renal (60-70% as unchanged drug and active metabolite); biliary/fecal ~20%.
Category C
Category C
Antidiarrheal
Antidiarrheal