In contrast, Type IV hypersensitivity reactions usually manifest between 24 and 48В h and are also known as delayed allergic contact dermatitis. dyspnea, cough wheezing, hypotension or tachycardia). urticaria or angioedema) or systemic symptoms (e.g. Type I hypersensitivity reactions usually manifest within a few minutes and can present with either local (e.g. Hypersensitivity reactions seen with local anesthetics can be broadly divided into Type1 and Type IV hypersensitivity reactions. In addition, hypersensitivity reactions are very common with local anesthetics. Systemic adverse effects of local anesthetics usually manifest with cardiovascular (tachycardia, hypotension, arrhythmias) or neurological (headache, dizziness, slurring of speech and/or seizures) complications. Systemic adverse effects can occur due to either direct injection into blood or systemic absorption occurring indirectly through local blood supply or lymph nodes. ДЄdverse effects associated with local anesthetics can be broadly divided into local adverse effects occurring at the site of its use or systemic adverse effects also known as local anesthetic systemic toxicity (LAST). Amide-type local anesthetics compared to ester-type anesthetics are more commonly used due to their better pharmacokinetic properties and lower incidence of adverse effects. Ester-type local anesthetics are metabolized by plasma pseudocholinesterase and their metabolites are excreted through urine. In contrast, examples of esters include procaine, chloroprocaine, tetracaine and benzocaine. Amide-type anesthetics are metabolized by the liver and should be carefully used in patients with liver and/or kidney impairments. Examples of amides include lidocaine, mepivacaine, prilocaine, ropivacaine articaine, levobupivacaine, bupivacaine, dibucaine and etidocaine. Based on their chemical structure, local anesthetics can be divided into two groups namely вЂamidesвЂ™ and вЂestersвЂ™. In addition, local anesthetics are also used for reliving localized pain. Local anesthetics are commonly used all over the world for a number of dental and outpatient surgical procedures. DвЂ™Souza MD, PhD, in Side Effects of Drugs Annual, 2020 Introduction

Pharmacology of local anaesthetics