UNUSUALLY PROLONGED DURATION OF SPINAL-ANESTHESIA FOLLOWING 2-PERCENTMEPIVACAINE

Background and Objectives: Spinal mepivacaine has been reported as a r eliable anesthetic for ambulatory anesthesia. Its pharmacologic proper ties are midway between those of bupivacaine and lidocaine, and it can be used in intermediate duration ambulatory surgical procedures. Meth ods: A patient taking clonidine transdermal patches (TTS) to control h igh blood pressure received spinal mepivacaine for surgical repair of a ruptured meniscus with arthroscopy. Results: The resulting duration of sensory and motor block were 12 and 8.5 hours, respectively. These are more than four times as long as the reported mean durations with t his spinal local anesthetic. We hypothesized that the use of clonidine via TTS for the previous 16 months contributed to this unusual delay of recovery from spinal anesthesia. Conclusions: Clonidine can increas e the duration of spinal anesthetics. Even though this well-known effe ct has been considered mostly beneficial, it can be an adverse effect when spinal ambulatory anesthesia is given to patients receiving cloni dine TTS or clonidine in other forms for long-term treatment of hypert ension or other diseases.