Prilocaine hydrochloride 2% hyperbaric solution for intrathecal injection: a clinical review

Prilocaine is a local anesthetic characterized by intermediate potency and duration and fast onset of action. As hyperbaric formulation of 5% solution, it was introduced and has been successfully used for spinal anesthesia since 1960. A new formulation of 2% plain and hyperbaric solution is currently available in Europe. Because of its lower incidence of transient neurological symptoms, prilocaine is suggested as substitute to lidocaine and mepivacaine in spinal anesthesia for ambulatory surgery, as well as a suitable alternative to low doses of long-acting local anesthetics. The National Library of Medicine database, the Excerpta Medica database, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials database, were searched for the period 1970 to September 2016, with the aim to identify studies evaluating the intrathecal use of 2% prilocaine. A total of 13 randomized clinical trials (RCTs), 1 observational study, 2 dose finding, and 4 systematic reviews has been used for this review. The studies evaluated showed that 2% hyperbaric prilocaine due to a favorable anesthetic and safety profile is an alternative drug to lidocaine and mepivacaine for spinal anesthesia of intermediate or short duration. In comparison with plain solutions, hyperbaricity remarkably accelerates the onset and offset times of intrathecal 2% prilocaine. Literature suggests a dose ranging between 40 and 60 mg of prilocaine for lower extremities and lower abdominal procedures lasting up to 90 min, whereas a dose ranging from 10 to 30 mg is appropriate for perineal surgery. Readiness for discharge occurs in ~4 h from spinal administration.