VASOCONSTRICTIVE EFFECTS OF COCAINE AND LIDOCAINE WITH EPINEPHRINE INTHE HAMSTER-CHEEK POUCH MODEL

Otolaryngologists frequently use cocaine and lidocaine with epinephrin e for their anesthetic and vasoconstrictive effects. However, no studi es have visually compared the vasoconstrictive effects of cocaine to l idocaine with epinephrine. This study used the everted hamster cheek p ouch model to assess the vasoconstrictive effects of cocaine and lidoc aine with epinephrine by measuring the diameter changes of arterioles. Our results showed that locally injected 1% lidocaine with 1:100,000 units epinephrine caused the greatest diameter reduction in arterioles to 32% of the initial resting diameter. Topical 1% lidocaine with 1:1 00,00 units epinephrine caused a gradual reduction in diameter with fi ndings equivalent to those of injected 1% lidocaine with 1:100,000 uni ts epinephrine at 30 minutes. Topical 5% cocaine HCl showed a minimal response, with a reduction to only 85% of the resting arteriolar diame ter. Topical NaCl and injected NaCl controls showed no significant art eriolar reduction. Vasoconstrictive differences between the preparatio ns were statistically significant (p < 0.05). Five percent cocaine is a much weaker vasoconstrictor than locally injected 1% lidocaine with 1:100,000 epinephrine.