XAAR (Pregabalin) is an analogue of the neurotransmitter gamma amino butyric acid (GABA). It has analgesic and anticonvulsant activity. Chemically pregabalin is described as (S)-3-(aminomethyl)- 5-methyl-hexanoic acid and the molecular formula is C8H17N02
MECHANISM OF ACTION
Pregabalin reduces neuronal calcium currents by binding to the alpha 2 delta subunit of voltage gated calcium channels in CNS tissues and this particular mechanism may be responsible for effects in neuropathic pain, anxiety and other pain syndromes. Pregabalin does not block sodium channels, is not active at opiate receptors and does not alter cyclooxygenase enzyme activity. It is inactive at serotonin and dopamine receptors and does not inhibit dopamine, serotonin or noradrenaline reuptake.
PHARMACOKINETICS
Absorption and Distribution: Following oral administration of pregabalin(Xaar) capsules under fasting conditions, peak plasma concentrations occur within 1.5 hours. Pregabalin oral bioavailability is > 90% and is independent of dose. Following single (25 to 300mg) and multiple doses (75 to 900mg/day) administration, maximum plasma concentrations (Cmax) and area under the plasma concentration time curve (AUC) values increase linearly. Following repeated administration, a steady state is achieved within 24 to 48 hours. Pregabalin does not bind to plasma proteins. The apparent volume of distribution of pregabalin following oral administration is approximately 0.5L/kg.
Metabolism and Elimination: Pregabalin undergoes negligible metabolism in humans. About 98% of the dose is excreted in the urine as an unchanged drug. The N-methylated derivative of pregabalin, found in urine, accounted for 0.9% of the dose. Pregabalin’s mean elimination half life is 6.3 hours and is eliminated from the systemic circulation primarily by renal excretion as an unchanged drug. Pregabalin is removed by haemodialysis.
Renal Insufficiency: Pregabalin clearance is nearly proportional to creatinine clearance. Pregabalin is effectively removed by haemodialysis (following 4 hour haemodialysis treatment plasma pregabalin concentrations are reduced by approximately 50%). Dose adjustments are required for patients on haemodialysis.
Elderly (Over 65 years of age): Pregabalin clearance tends to decrease with increasing age. This decrease in pregabalin oral clearance is consistent with a decrease in creatinine clearance associated with increasing age. Reduction of pregabalin(Xaar) dose may be required in patients with age-related compromised renal function.
INSTRUCTIONS
Store in a cool & dry place below 25°C.
Protect from light, heat and moisture.
Keep out of reach of children.