Some Recent Studies on the Clinical Pharmacology of Local Anesthetics of Practical Significance

Intranasal anesthetic effects of lidocaine and tetracaine compared

“…In two follow‐up articles, it was demonstrated that tetra caine, when applied topically to the mucous membranes of the pharynx and trachea, is absorbed systemically such that blood levels are comparable with those after intravenous injection 12 , 13 . Vasoconstrictors did not retard the absorption of local anesthetic from the mucous membranes tested, but absorption of local anesthetic from the nasal mucosa was not evaluated 14 . As a result of these reports, the use of tetracaine as a topical anesthetic fell into disfavor.…”

“…With the increased use of functional endoscopic sinus surgery, the number of intranasal procedures performed with local anesthesia will probably increase. For many years, cocaine was the preferred topical local anesthetic agent used for intranasal procedures, but a replacement has been sought because of its increasing cost, decreasing availability, toxicity, and habit‐forming potential 14 …”

The Use of Tetracaine 0.25% Solution in Nasal Packing Removal

“…9,10 Absorption of local anesthetics from the nasal mucosa was not evaluated. 11 As a result of these reports, the use of tetracaine as a topical anesthetic fell into disfavor. 4,6 Intranasal anesthetics are absorbed systemically to some degree.…”

Aspects of the Pharmacology of Local Anaesthetic Agents

“…The addition of adrenaline to solutions of mepivacaine and prilocaine has been claimed not to alter the mayirnai blood concentration of the local anaesthetic agent in brachial blocks (Dhuner et al, 1965) or in extradurals (Braid and Scott, 1965Scott, , 1966. And it is thought not to prolong the duration of action of local anaesthetics on mucous membranes, nor does it hinder their rapid absorption therefrom (Campbell, 1957;Adriani and Zepernick, 1963).…”

“…scand. ) several cases may be explained by the gross overdose administered, often in combination with thê discriminate use of central depressant or stimulant drugs for the treatment of convulsions and hypotension (Moore, 1966;Richards, Smith and Katz, 1968;Adriani, 1968). It has been clearly demonstrated, in both animal experiments and in man that local anaesthetic agents administered in doses sufficient to attain convulsant blood or plasma levels, or approaching thereto, do not have a deleterious effect on the circulation ( fig.…”