Key result
Carisoprodol showed no evidence of direct muscle relaxation but produced sedation and psychomotor impairment, most prominently at 1.5 hours after dosing, with no withdrawal symptoms detected.
Why the study?
Centrally acting skeletal muscle relaxants like carisoprodol treat acute musculoskeletal conditions, but their precise mode of action has not been characterized.
Does carisoprodol produce direct muscle relaxation or act through sedation in healthy volunteers?
RCT (n=13)
Double-blind
randomized
Does carisoprodol produce direct muscle relaxation or act through sedation in healthy volunteers?
Carisoprodol appears to act primarily through sedation rather than direct muscle relaxation, with low risk of dependence at recommended doses.
Supports reevaluating carisoprodol as sedative rather than myorelaxant; challenges mechanistic assumptions and informs prescribing in practice.
Centrally acting skeletal muscle relaxants (CMR) such as carisoprodol are used to treat acute, painful musculoskeletal conditions, though its precise mode of action has not been characterized. A double-blinded, placebo-controlled, randomized clinical trial was designed to evaluate the pharmacokinetics-pharmacodynamics (PKPD) of CMR after single (350 mg), double (700 mg), and multiple doses (up to 350 mg/8 h, 14 days) of carisoprodol. Muscular (Electromyogram-EMG, muscular strength dynamometry), central (sedation), and tolerability (psychomotor activity test, adverse events) parameters, as well as withdrawal symptoms, were evaluated. Thirteen healthy volunteers were enrolled. No evidence of direct muscle relaxation was evidenced, but some differences on sedation were evidenced throughout the study, suggesting that CMRs act, at least partly, through sedation. Most significant differences were detected at 1.5 h after dosing. The effect on psychomotor impairment was variable, most prominently after 1.5 h, too, suggesting that it is produced by carisoprodol rather than by meprobamate. No withdrawal symptoms were detected, so the risk of dependence following maximum doses and duration of treatment recommended, and under medical supervision, should be low.
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Calvo et al. (2022) conducted an RCT in Healthy volunteers (n=13). Carisoprodol vs. Placebo was evaluated on Pharmacokinetics-pharmacodynamics (PKPD) including muscular, central, and tolerability parameters. Carisoprodol showed no evidence of direct muscle relaxation but produced sedation and psychomotor impairment, most prominently at 1.5 hours after dosing, with no withdrawal symptoms detected.
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