A clinical double-blind study of dibucaine and tetracaine in spinal anesthesia.

The effects of 0.25% dibucaine and 0.5% tetracaine used for the production of spinal anesthesia were compared in 30 healthy surgical patients. Fifteen patients were assigned to each of the two agents using a randomized, observer and patient-blinded method. Success rate, times of onset and regression of analgesia, intensity of motor blockade, and cardiovascular effects were assessed and the results were analyzed statistically. There were no differences in success rate, in latency, or in duration of action between the two spinal anesthetic agents. Tetracaine was found to be associated with a significantly greater decrease in arterial pressure and more complete motor blockade.