THE TOXICITY, ANESTHETIC POTENCY AND SOME PHARMACOLOGICAL ACTIONS OF A NEW LOCAL ANESTHETIC BETA-DIETHYLAMINOETHYL ESTER OF 4-AMINO-1-NAPHTHOIC ACID (NAPHTHOCAINE)

¹ From the Department of Pharmacology, Jefferson Medical College, Philadelphia, Pennsylvania

1. Studies were made on the toxicity, anesthetic potency and pharmacological actions of the mono-hydrochloride of beta-diethylaminoethyl ester of 4-amino-1-naphthoic acid (naphthocaine).

2. The subcutaneous LD 50 of naphthocaine for white mice was found to be 107 mgm. per kilogram. For rabbits the LD 50 was noted to be 54 mgm. per kilogram. The LD 50 of cocaine for white mice was found to be 127 mgm. per kilogram.

3. Minimum effective concentrations of naphthocaine and cocaine were found to be 0.025 and 0.25 per cent respectively.

4. Using 1.0 as the anesthetic index for cocaine, naphthocaine will in comparison have an index of 8.4.

5. Naphthocaine produces clonic-tonic convulsions.

6. Using the rabbit cornea as the test object, naphthocaine was found to be a more efficient topical anesthetic than cocaine of the same concentration. With the use of the guinea pig, intradermal injections, naphthocaine produced anesthesia of longer duration than that observed by procaine of the same concentration.

7. Naphthocaine does not produce corneal ulceration in cats.

8. Naphthocaine injected intravenously in dogs produces a temporary fall in blood pressure and a temporary depression of respiration.

9. Following the intravenous injection of naphthocaine in dogs no constant effect in the size of the spleen and cardiac rate was noted.

10. In experimental animals naphthocaine produces death by respiratory failure.