Lidocaine subcutaneous injection

Figure 19-9 Subcutaneous injection of 1% lidocaine with epinephrine at base of papilloma provides adequate anesthesia for excision.

Local anesthetics are widely used to provide anesthesia via local subcutaneous Injection topical application to skin and mucous membranes and epidural, spinal, and regional nerve blocks. In addition, lidocaine (see p 462) is used intravenously as an antiarrhythmic agent and cocaine (see p 171) is a popular drug of abuse. Gommonly used agents are divided into two chemical groups ester-linked and amide-linked (Table 11-2). 

Intramuscular (i.m.) injections are an alternative when i.v. access is not available. For example, lidocaine has been shown to be rapidly absorbed after i.m. injection, with the deltoid muscle being a superior site to either the buttocks or lateral thigh. Many drugs show great variability in absorption after intramuscular or subcutaneous injection. Because of the uncertainty in the bioavailability of the drug from these routes, in an emergency the i.v. route is clearly superior for rapid administration of a defined dose. 

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