Extreme care must be used with application to the lip because of the possibility of systemic absorption of the cocaine - inappropriate supervision of an infant or young child could result in serious consequences. T.A.C. is not as effective on the less vascularized tissues of the extremities and torso. Although moderate anesthetic effects are noted on adults, supplemental injections of local anesthesia, such as Lidocaine are usually required. Decreasing nerve transmission at the site of application provides limited, brief, local anesthetic effects. Temporary relief of discomfort and a dry, bloodless field for suturing is created by the combination of these three medications.
Tetracaine inhibits initiation and conduction of nerve impulses at the site of application.
Adrenaline causes vasoconstriction, decreasing the systemic absorption of medications, as well as reducing the flow of blood to the wound site, allowing for a dry tissue field to repair. Cocaine produces prolonged vasoconstriction and rapidly blocks initiation and conduction of nerve impulses where applied. Tetracaine is a potent amino ester. Esters are metabolized by plasma and liver cholinesterases. Effects of topical Tetracaine last about 45 minutes.