Pharmacotherapeutic group: Antiinflammatory and antirheumatic products, non-steroids, oxicams. ATC code: M01AC05.
Pharmacology: Pharmacodynamics: Larfix contains Lornoxicam which is a non-steroidal anti-inflammatory drug with analgesic properties and belongs to the class of oxicams. Lornoxicam's mode of action is mainly related to the inhibition of the prostaglandin synthesis (inhibition of the cyclooxygenase enzyme) leading to desensitisation of peripheral nociceptors and consequently inhibition of inflammation. A central effect on nociception, which seems to be independent of anti-inflammatory effects has also been suggested.
Lornoxicam has no effect on vital signs (e.g. body temperature, respiratory rate, heart rate, blood pressure, ECG, spirometry).
Pharmacokinetics: Absorption: Lornoxicam is absorbed rapidly and almost completely from the gastrointestinal tract. Maximum plasma concentrations are achieved after approx. 1-2 hours. The absolute bioavailability of lornoxicam is 90-100%. No first-pass effect was observed. The mean elimination half-life is 3 to 4 hours. Simultaneous intake of lornoxicam with meals reduced Cmax by approx. 30%. Tmax was increased from 1.5 to 2.3 hours. The absorption of lornoxicam (calculated on AUC) can be reduced up to 20%.
Distribution: Lornoxicam is found in the plasma in unchanged form and as its hydroxylated metabolite. The plasma protein binding of lornoxicam is 99% and not concentration dependent.
Metabolism: Lornoxicam is extensively metabolised in the liver, primarily to the inactive 5-hydroxylornoxicam by hydroxylation. CYP2C9 is involved in this biotransformation of lornoxicam. Due to genetic polymorphism, slow and extensive metabolisers exist for this enzyme, which could result in markedly, increased plasma levels of lornoxicam in slow metabolisers. The hydroxylated metabolite exhibits no pharmacological activity. Lornoxicam is metabolised completely, and approximately 2/3 is eliminated via the liver and 1/3 via the kidneys as inactive substance.
Elimination: The mean elimination half-life of the parent compound is 3 to 4 hours. After oral administration about 50% is excreted in the faeces and 42% through the kidneys, mainly as 5-hydroxylornoxicam. The elimination half-life of 5-hydroxylornoxicam is about 9 hours after a parenteral single or twice daily dose.
In elderly patients above age 65, the clearance is reduced with 30-40%. Apart from reduced clearance, there is no significant change in the kinetic profile of lornoxicam in elderly patients. There is no significant change in the kinetic profile of lornoxicam in patients with renal or hepatic failure, except for accumulation in patients with chronic liver disease after 7 days of treatment with daily doses of 12 and 16 mg.