CLINICAL PHARMACOKINETICS OF ARTICAINE

Articaine is the most widely used local anaesthetic agent in dentistry in a number of European countries. The amide structure of articaine i s similar to that of other local anaesthetics, but it contains an addi tional ester group which is quickly hydrolysed by esterases. High perf ormance liquid chromatography has been used to determine the concentra tions of articaine and its metabolite articainic acid in serum. Rapid sample preparation is critical in the accurate determination of artica ine serum concentrations, since blood and serum are the sites of metab olism. The time to maximum drug concentrations of articaine occurs abo ut 10 to 15 minutes after submucosal injection of articaine 4% 80mg, i rrespective of epinephrine (adrenaline). The mean maximum plasma drug concentration is about 400 mu g/L for articaine with epinephrine 1 : 2 00 000 and 580 mu g/L for articaine without epinephrine. The eliminati on half-time of articaine is about 20 minutes. The rapid breakdown of articaine to the inactive metabolite articainic acid is related to a v ery low systemic toxicity and consequently to the possibility of repea ted injections. Equal analgesic efficacy along with lower systemic tox icity (i.e. a wide therapeutic range) permits the use of articaine in higher concentrations than other amide-type local anaesthetics. Comple te anaesthesia can be observed in nearly 90% of all cases, using artic aine 4% 60 to 80mg with epinephrine 1 : 200 000. Articaine is better a ble to diffuse through soft tissue and bone than other local anaesthet ics. The concentration of articaine in the alveolus of a tooth in the upper jaw, after extraction was about 100 times higher than that in sy stemic circulation. The plasma protein binding rate of articaine and a rticainic acid is 70%. It has been concluded that an unintentional int ravascular injection of articaine 80mg does not cause toxic effects in healthy individuals.