Cetra Tablet

Description: Tramadol is a centrally acting opioid analgesic which binds to mu-opioid receptors and weakly inhibits the reuptake of norepinephrine and serotonin. Paracetamol, a para-aminophenol derivative, has analgesic, antipyretic and weak anti-inflammatory activity. Together, tramadol and paracetamol has faster onset of action compared to tramadol alone and longer duration of action compared to paracetamol alone.
Duration: 5 hr.
Pharmacokinetics:
Absorption: Readily absorbed from GI tract. Tramadol: Bioavailability: Approx 70-75% (oral); 100% (IM). Paracetamol: Time to peak plasma concentration: 10-60 min.
Distribution: Widely distributed, crosses the placenta and distributesd into the breast milk. Plasma protein binding: Approx 20% (tramadol); negligible (paracetamol).
Metabolism: Tramadol: Undergoes N- and O-demethylation by CYP3A4 and CYP2D6 isoenzymes and also by glucuronidation and sulfation. Paracetamol: Hepatic via glucuronic and sulfuric acid conjugation.
Excretion: Tramadol: Via urine as metabolites. Elimination half-life: Approx 6 hr. Paracetamol: Via urine as glucuronide and sulfate conjugates; <5% as unchanged drug Elimination half life: Approx 1-3 hr.