Comparative Pharmacology
Head-to-head clinical analysis: MARINOL versus VONTROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MARINOL versus VONTROL.
MARINOL vs VONTROL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dronabinol is a cannabinoid receptor agonist at CB1 and CB2 receptors. It stimulates appetite and reduces nausea/vomiting via central CB1 receptor activation.
VONTROL (trimethobenzamide) acts centrally to inhibit the chemoreceptor trigger zone (CTZ) in the medulla oblongata, thereby suppressing nausea and vomiting. Its exact mechanism is not fully understood but may involve antagonism of dopamine D2 receptors and serotonin 5-HT3 receptors.
Dronabinol (Marinol) 2.5 mg orally twice daily, titrated to 5–20 mg daily in divided doses; max 20 mg/day. For chemotherapy-induced nausea/vomiting: 5 mg/m² orally 1–3 hours before chemotherapy, then every 2–4 hours up to 6 doses/day. For anorexia: 2.5 mg orally twice daily (before lunch and dinner).
10 mg orally twice daily; maximum 20 mg/day.
None Documented
None Documented
Dronabinol terminal half-life is 25–36 hours in adults, with a prolonged elimination phase (25–36 h) due to enteric recirculation. Chronic users may exhibit a shorter half-life due to enzyme induction.
12 hours; prolonged in renal impairment (up to 24 hours in ESRD)
Primarily fecal (65%) with biliary excretion; renal excretion of metabolites accounts for ~20% (mostly as glucuronide conjugates). Less than 5% of unchanged drug is excreted renally.
Renal: 60% unchanged; fecal: 30% (biliary); hepatic metabolism: 10%
Category C
Category C
Antiemetic
Antiemetic