Severe adverse reactions to dental local anaesthetics: prolonged mandibular and lingual nerve anaesthesia

Abstract

Background: Prolonged anaesthesia may occur following dental local anaesthetic blocks. This paper reviews the possible mechanisms of injury. Direct injury to the nerve by the needle, although commonly thought to be the mechanism, is unlikely. It is much more likely that the injury is from neurotoxicity and ⁄ or interference with the vascularization of the nerve. Methods: Estimation of the frequency of injury was complicated by the fact that although local anaesthetics are prescription-only (S4) drugs, they are supplied without prescription by dental supply houses. Unlike all other S4 drugs, there is no statutory requirement to record supply. The pharmaceutical and supply houses relied on that and 'commercial confidentiality' to not supply information. Results: An informed estimate of 1 in 27 415 was made but this figure has wide confidence limits. Management of cases of prolonged anaesthesia following local anaesthetic injection is discussed. Conclusions: Patients who suffer this uncommon complication suffer considerable distress and feel injured, so care must be exhibited in their management. Specialist referral is recommended.

Higher concentration local anaesthetics causing prolonged anaesthesia. Do they? A literature review and case reports

“…The recent Australian study found an incidence of 1 in 27 415 although this figure has wide confidence limits. 2 Prolonged anaesthesia may also occur when lower 2% local anaesthetic agents are used. 2 The key issue is that the evidence indicates that there is a greater risk with a higher concentration of local anaesthetics.…”

“…2 Prolonged anaesthesia may also occur when lower 2% local anaesthetic agents are used. 2 The key issue is that the evidence indicates that there is a greater risk with a higher concentration of local anaesthetics. The increased risk is conservatively estimated at 5-to 7-fold.…”

“…Although it is commonly thought that electric shock pain on injection or repeat injections are associated with an increase in prolonged anaesthesia, this is not supported by the literature. 2,6 They all suffered prolonged abnormal sensation in the mandibular or lingual nerves. None of these cases have yet to be fully resolved.…”

“…These have recently been reported. 2,3 In the development of these studies, it is evident that there is concern in the international literature of a risk of a relation between increased concentration and increased neurotoxicity. [4][5][6][7][8][9][10][11][12] It has been claimed by clinical observation that 4% articaine has a faster onset of anaesthesia and fails to be effective less often; two features that practitioners consider important.…”

“…2 In this study, the international literature was reviewed in an attempt to determine the risk of increased concentration of local anaesthetic agents on the incidence of prolonged anaesthesia.…”