Comparative Pharmacology
Head-to-head clinical analysis: DOXYLAMINE SUCCINATE AND PYRIDOXINE HYDROCHLORIDE versus PROMETHAZINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DOXYLAMINE SUCCINATE AND PYRIDOXINE HYDROCHLORIDE versus PROMETHAZINE.
DOXYLAMINE SUCCINATE AND PYRIDOXINE HYDROCHLORIDE vs PROMETHAZINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Doxylamine succinate is a histamine H1 receptor antagonist with sedative properties; pyridoxine hydrochloride is a vitamin B6 derivative that acts as a coenzyme in amino acid, carbohydrate, and lipid metabolism. The combination is believed to reduce nausea and vomiting through central anticholinergic effects and pyridoxine supplementation.
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.
1 tablet (doxylamine succinate 10 mg / pyridoxine hydrochloride 10 mg) orally twice daily (morning and evening), increased to three times daily if needed (one tablet in the morning, one in the afternoon, and two at bedtime). Maximum: 4 tablets per day.
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.
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
moderateDoxylamine: terminal half-life 10-12 hours; steady state reached in 3-4 days. Pyridoxine: half-life 15-20 days for body stores, but plasma half-life of pyridoxal phosphate ~15-30 minutes.
Terminal elimination half-life 9-16 hours; may be prolonged in hepatic impairment.
Doxylamine: ~60% renal as unchanged drug and metabolites; Pyridoxine: primarily renal as 4-pyridoxic acid and other metabolites. Up to 70% of pyridoxine metabolites excreted in urine within 24 hours.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal minor.
Category C
Category A/B
Antiemetic
Antihistamine / Antiemetic
Promethazine + Clotrimazole
"The metabolism of Clotrimazole can be decreased when combined with Promethazine."