Vasoconstrictive effects of cocaine and lidocaine with epinephrine in the hamster cheek pouch model.

Otolaryngologists frequently use cocaine and lidocaine with epinephrine for their anesthetic and vasoconstrictive effects. However, no studies have visually compared the vasoconstrictive effects of cocaine to lidocaine with epinephrine. This study used the everted hamster cheek pouch model to assess the vasoconstrictive effects of cocaine and lidocaine 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 1:100,000 units epinephrine caused a gradual reduction in diameter with findings equivalent to those of injected 1% lidocaine with 1:100,000 units epinephrine at 30 minutes. Topical 5% cocaine HCl showed a minimal response, with a reduction to only 85% of the resting arteriolar diameter. Topical NaCl and injected NaCl controls showed no significant arteriolar reduction. Vasoconstrictive differences between the preparations were statistically significant (p < 0.05). Five percent cocaine is a much weaker vasoconstrictor than locally injected 1% lidocaine with 1:100,000 units epinephrine.