Adverse Drug Reactions To Local Anesthesia

Dent Clin N Am 46 (2002) 747–757

Adverse drug reactions to local anesthesia
Richard L. Finder, DMD, MSa,b, Paul A. Moore, DMD, PhD, MPHc,*
Department of Physiology and Pharmacology, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA b Ambulatory Anesthesia Associates, 2 Parkway Center, Suite G-1, Pittsburgh, PA 15220, USA c Department ofDental Public Health, University of Pittsburgh School of Dental Medicine, 552 Salk Hall, 3501 Terrace Street, Pittsburgh, PA 15261, USA
a

A dentist’s ability to safely administer regional anesthesia is essential for dental practice. Local anesthetic solutions used in the United States for dental anesthesia are formulated with several components. The contents of a standard local anesthetic cartridgemay include an amide or ester local anesthetic drug, an adrenergic vasoconstrictor, and an antioxidant. In susceptible patients, any of these components may induce systemic, dose-dependent adverse reactions. Although extremely rare, allergic reactions may also occur. Signs and symptoms of the various adverse reactions associated with local anesthetics are quite distinctive, permitting rapiddiagnosis and treatment (see box below). Serious reactions are extremely infrequent and, when treated properly, are unlikely to result in significant morbidity or mortality. Local anesthesia toxicity When the local anesthetic contained in a dental cartridge diffuses away from the site of injection, it is absorbed into the systemic circulation where it is metabolized and excreted. The doses of a localanesthetic used in dentistry are usually minimal, and systemic effects are therefore uncommon. However, if an inadvertent vascular injection occurs or when repeated injections are administered, blood levels of a local anesthetic may become elevated. Signs and symptoms Initially, excitatory reactions to local anesthetic overdose are seen such as tremors, muscle twitching, shivering, and clonic-tonicconvulsions [1–3].
* Corresponding author. E-mail address: pam7@pitt.edu (P.A. Moore). 0011-8532/02/$ - see front matter Ó 2002, Elsevier Science (USA). All rights reserved. PII: S 0 0 1 1 - 8 5 3 2 ( 0 2 ) 0 0 0 1 8 - 6

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R.L. Finder, P.A. Moore / Dent Clin N Am 46 (2002) 747–757

Diagnosis of local anesthesia reactions Local anesthesia toxicity Initial symptoms include tremors, muscletwitching, and convulsions. Following the initial phase, respiratory depression, lethargy, and loss of consciousness are possible. Cardiovascular depression may induce hypotension at extremely high blood concentrations. Hypoxia secondary to respiratory depression can rapidly produce the most serious outcomes including cardiovascular collapse, brain damage, and death. Vasoconstrictor reactionsInitial signs of the sympathetic nervous system stimulation include palpitations, increased heart rate, and elevated blood pressure. Anxiety, nervousness, and fear are often associated with the palpitations. With severe overdose, arrhythmia, stroke, and myocardial infarction are possible. Methemoglobinemia Because methemoglobinemia is caused by metabolites of prilocaine, symptoms frequently do notoccur for 1–3 hours following treatment. Methemoglobinemia also has been reported following benzocaine and other local anesthetics. Cyanosis without signs of respiratory distress may be apparent when methemoglobin levels reaches 10–20%. Vomiting and headache have been described. At higher blood concentrations of methemoglobin, dyspnea, seizures, stupor, coma, and death are possible. Allergicreactions to local anesthetics Mild manifestations of allergy to systemic drugs include urticaria, erythema, and intense itching. More severe reactions may include angioedema and respiratory distress. Although extremely unlikely, one should be prepared for the life-threatening anaphylactic responses including dyspnea, hypotension, and loss of consciousness. Sulfite antioxidant reactions Asthma-like signs...