Articaine hydrochloride with adrenaline

Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Articaine is a local anaesthetic that has been approved overseas for several years. Like other amide anaesthetics, articaine blocks nerve conduction when it is infiltrated around a nerve. This action is prolonged by combining the drug with a vasoconstrictor such as adrenaline.

The combination of articaine and adrenaline can be used for local or regional anaesthesia for dental procedures. Anaesthesia begins within six minutes and lasts for an hour. The half-life of articaine is approximately 1.8 hours. It is metabolised and then mainly excreted in the urine.

Articaine 4% with adrenaline was compared with lignocaine 2% with adrenaline in three double-blind trials. The drugs were given as submucosal infiltrations or nerve blocks before dental procedures. There were no significant differences, on a visual analogue pain scale, between the anaesthesia achieved by the 882 patients given articaine and the 443 given lignocaine^.1

Approximately one patient in five reported an adverse event after dental anaesthesia. The most common complaint in both groups was postoperative pain, followed by headaches and facial swelling. Although the incidence was less than 1%, paraesthesia and hypoesthesia affected more of the patients treated with articaine. Although some patients developed changes in pulse and blood pressure these could have been related to anxiety about the injection and the procedure.² As with other local anaesthetics it is important that the drug is not injected into a blood vessel. The dental surgery should have resuscitation equipment in case of cardiovascular collapse or convulsions. Although the immunogenic potential of articaine is probably low, it is contraindicated in patients with an allergy to sodium metabisulfite as the formulation includes this antioxidant.

Widespread use of articaine has allowed rare adverse effects to emerge. For example, there may be paralysis of the ocular muscles after posterior, superior alveolar injections of articaine.³ Although the efficacy of articaine appears to equal that of lignocaine, there does not seem to be a compelling clinical reason for Australian dentists to change their choice of local anaesthetic.