Source: Health Products Regulatory Authority (ZA) Revision Year: 2023 Publisher: Macleods Pharmaceuticals SA (Pty) Ltd, Office block 1, Bassonia Estate Office Park (East), 1 Cussonia Drive, Bassonia Rock, Ext. 12, Alberton, South Africa
Pharmaceutical groups: A.2.9.Other analgesics
ATC code: N02AX02
Tramadol hydrochloride is a centrally acting analgesic with binding to specific opioid receptors. It is a non-selective, agonist at mu (μ), delta (δ) and kappa (k) opioid receptors with a higher affinity for the μ receptor. Other mechanisms, which contribute to its analgesic effect, are inhibition of neuronal re-uptake of noradrenaline acts as an anti-inflammatory, analgesic and as well as the enhancement of serotonin release. The relationship between serum concentrations and the analgesic effect is dose-dependent, but varies considerably. Patients devoid of CYP2D6 may need higher doses of tramadol, to achieve adequate analgesia.
After oral administration of DOLTREX 50 MG tablets, tramadol hydrochloride is absorbed with an absorption half-life (t½ka) of 0, 38 ± 0, 18 hours.
The mean systemic bioavailability is 68%, independent of food intake.
Tramadol has a linear pharmacokinetic profile within the therapeutic dosage range.
The elimination half-life is 5 to 7 hours. Tramadol is mainly metabolised in the liver (90%).
Tramadol hydrochloride and its metabolites are almost completely excreted by the renal route (95%). Biliary excretion of these components is quantitatively insignificant and is therefore subject to hepatic metabolism and renal elimination.
The terminal half-life (t½β) is prolonged in impaired hepatic or renal function. In patients with liver cirrhosis, the mean t½β of tramadol was 13, 3 ± 4, 9 h, t½,β/M1 18, 5 ± 9, 4 h, in patients with renal insufficiency (creatinine clearance ≤5 ml/min) the values were 11, 0 ± 3, 2 h (tramadol) and 16, 9 ± 3, 0 h (M1) respectively.
The inhibition of one or both types of isoenzymes CYP3A4 and CYP2D6 involved in the biotransformation of tramadol may affect the plasma concentration of tramadol or its active metabolite.
Tramadol hydrochloride crosses the blood-brain and placental barrier. Small amounts are excreted in breast milk unchanged or as the metabolite M1.
Not available.
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