Drug Allergies and Implications for Dental Practice
Adverse reactions to medications prescribed or administered in dental practice can be worrying. Most of these reactions are somewhat predictable based on the pharmacodynamic properties of the drug. Others, such as allergic and pseudoallergic reactions, are generally unpredictable and unrelated to normal drug action. This article will review immune and nonimmune-mediated mechanisms that account for allergic and related reactions to the particular drug classes commonly used in dentistry. The appropriate management of these reactions will also be addressed.Abstract

Managing history of local anesthetic allergy. Carefully question the patient regarding the nature of the reaction. If allergist referral is elected, discuss the case history with the physician and request testing for plain lidocaine, which the allergist has available, along with plain prilocaine or mepivacaine, which you will need to provide. (Epinephrine cannot be included, as it inhibits autacoids and renders any testing invalid.) Also address the possibility of bisulfite allergy.

Pseudoallergy and altered arachidonic acid metabolism. Aspirin and the nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit 2 families of cyclooxygenases (COX-1 and COX-2) from converting arachidonic acid to various prostanoids, including prostaglandins, prostacyclin, and thromboxanes. This in turn reduces the eventual effects normally produced by these prostanoids and leaves more arachidonic acid available as a substrate for lipoxygenase to produce leukotrienes. Inhibiting COX-1 in particular also diminishes the inhibitory effect of prostaglandin E2 (PGE2) on lipoxygenase activity. The increased synthesis of leukotrienes may produce anaphylactoid syndromes in susceptible patients. Selective inhibition of COX-2 is less likely to produce this altered metabolism.

Managing history of penicillin allergy.

Management of allergic reactions.
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