Comparative Pharmacology
Head-to-head clinical analysis: DEXTROMETHORPHAN POLISTIREX versus TUZISTRA XR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEXTROMETHORPHAN POLISTIREX versus TUZISTRA XR.
DEXTROMETHORPHAN POLISTIREX vs TUZISTRA XR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dextromethorphan polistirex is an NMDA receptor antagonist and sigma-1 receptor agonist. It inhibits serotonin reuptake and acts on the brain stem cough center to elevate the threshold for coughing.
Tuzistra XR is a combination of codeine (an opioid agonist) and promethazine (a phenothiazine derivative with antihistaminic, sedative, and anticholinergic effects). Codeine binds to mu-opioid receptors in the CNS, inhibiting cough reflex. Promethazine acts as a histamine H1 receptor antagonist and may have additional central anticholinergic and sedative effects.
30-60 mg orally every 12 hours; not to exceed 120 mg in 24 hours.
Initial: 25 mg orally twice daily; may increase to 50 mg twice daily after 1 week based on tolerability; maximum 50 mg twice daily.
None Documented
None Documented
Terminal half-life: 13–19 hours; clinical context: extended-release formulation due to polistirex complex; time to steady-state: ~3 days
Terminal elimination half-life is 7 hours for the parent drug; clinically, this supports twice-daily dosing for sustained symptom relief.
Renal: ~45% as unchanged drug and metabolites (dextrorphan conjugates); fecal: <2%; biliary: minimal
Primarily hepatic metabolism via glucuronidation; approximately 20% of the dose is excreted unchanged in urine, and 80% is eliminated as metabolites in feces via biliary excretion.
Category C
Category C
Antitussive
Antitussive/decongestant combination