Spinal prilocaine

Determination of the ED95 of intrathecal hyperbaric prilocaine with sufentanil for scheduled cesarean delivery: a dose-finding study based on the continual reassessment method

BACKGROUND

Scheduled cesarean section is routinely performed under spinal anesthesia using hyperbaric bupivacaine. The current study was undertaken to determine the clinically relevant 95% effective dose of intrathecal 2% hyperbaric prilocaine co-administered with sufentanil for scheduled cesarean section, using continual reassessment method.

METHODS

We conducted a dose-response, prospective, double-blinded study to determine the ED95 values of intrathecal hyperbaric prilocaine used with 2,5 mcg of sufentanil and 100 mcg of morphine for cesarean delivery. Each parturient enrolled in the study received an intrathecal dose of hyperbaric prilocaine determined by the CRM and the success or failure of the block was assessed as being the primary endpoint.

RESULTS

The doses given for each cohort varied from 35 to 50 mg of HP, according to the CRM, with a final ED95 lying between 45 and 50 mg of Prilocaine after completion of the 10 cohorts. Few side effects were reported and patients were globally satisfied.

CONCLUSIONS

The ED95 of intrathecal hyperbaric prilocaine with sufentanil 2.5 μg and morphine 100 μg for elective cesarean delivery was found to be between 45 and 50 mg. It may be an interesting alternative to other long-lasting local anesthetics in this context.

TRIAL REGISTRATION

The study was registered on January 30, 2017 - retrospectively registered - and results posted at the public database clinicaltrials.gov ( NCT03036384 ).

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.

Prilocaine spinal anesthesia for ambulatory surgery: A review of the available studies

Transient neurologic symptoms (TNS) led to the abandonment of intrathecal lidocaine. We reviewed the published literature for information about the duration of action and side effects of intrathecal prilocaine, which has been recently reintroduced in Europe. Medline and EMBASE databases were searched for the time period from 1966 to 2015. Fourteen prospective and one retrospective study were retrieved. The duration of the surgical block can be adjusted using doses between 40 and 80mg. Hyperbaric prilocaine in doses as low as 10mg can be used for perianal procedures. Four cases of TNS in 486 patients were reported in prospective studies, and none in 5000 cases in a retrospective data set. Spinal prilocaine appears to be safe and reliable for day case anesthesia. However, as chloroprocaine has a shorter duration and a lower risk of TNS and urinary retention, the indications for prilocaine remain to be defined.