Comparative Pharmacology
Head-to-head clinical analysis: FAYOSIM versus PROMETHAZINE DM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FAYOSIM versus PROMETHAZINE DM.
FAYOSIM vs PROMETHAZINE DM
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
FAYOSIM (plecanatide) is a guanylate cyclase-C (GC-C) agonist. It binds to GC-C receptors on the luminal surface of intestinal epithelial cells, activating the receptor and increasing intracellular cyclic guanosine monophosphate (cGMP) levels. Elevated cGMP stimulates chloride and bicarbonate secretion into the intestinal lumen, enhancing fluid secretion and accelerating gastrointestinal transit, thereby promoting bowel movements.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist, antiemetic via blockade of dopamine D2 receptors in the chemoreceptor trigger zone, and sedative via central anticholinergic effects. Dextromethorphan is an NMDA receptor antagonist and sigma-1 receptor agonist, suppressing cough by central action on the cough center.
10 mg orally once daily
2 teaspoonfuls (10 mL) orally every 4-6 hours, not to exceed 8 teaspoonfuls (40 mL) per 24 hours.
None Documented
None Documented
12-16 hours in healthy adults; prolonged to 20-30 hours in moderate renal impairment (CrCl <50 mL/min) requiring dose adjustment.
16-19 hours (terminal); note: effect may last longer due to active metabolites and tissue binding
Primarily renal elimination, 80% unchanged drug in urine; 15% biliary/fecal; 5% metabolized.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal (20-30%)
Category C
Category A/B
Antihistamine
Antihistamine / Antiemetic