Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE versus VONTROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE versus VONTROL.
PROMETHAZINE vs VONTROL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Promethazine is a phenothiazine derivative that acts as a potent histamine H1 receptor antagonist, thereby blocking the effects of histamine. It also has central anticholinergic, antiemetic, and sedative properties, likely mediated through antagonism at muscarinic, dopamine D2, and serotonin receptors in the brain.
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.
12.5-25 mg IM or IV every 4-6 hours; also 25 mg PO or PR every 6-8 hours. Maximum 100 mg/day.
10 mg orally twice daily; maximum 20 mg/day.
None Documented
None Documented
Clinical Note
moderatePromethazine + Risedronic acid
"Promethazine can cause an increase in the absorption of Risedronic acid resulting in an increased serum concentration and potentially a worsening of adverse effects."
Clinical Note
moderatePromethazine + Methylphenidate
"Promethazine can cause an increase in the absorption of Methylphenidate resulting in an increased serum concentration and potentially a worsening of adverse effects."
Clinical Note
moderatePromethazine + Artesunate
"The serum concentration of Artesunate can be increased when it is combined with Promethazine."
Clinical Note
moderateTerminal elimination half-life 9-16 hours; may be prolonged in hepatic impairment.
12 hours; prolonged in renal impairment (up to 24 hours in ESRD)
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal minor.
Renal: 60% unchanged; fecal: 30% (biliary); hepatic metabolism: 10%
Category A/B
Category C
Antihistamine / Antiemetic
Antiemetic
Promethazine + Clotrimazole
"The metabolism of Clotrimazole can be decreased when combined with Promethazine."