Paracetamol 325 mg/tramadol 37.5 mg effect on pain during needle electromyography: a double-blind crossover clinical trial

Needle insertion during electromyography (EMG) may cause varying levels of pain that could lead to inaccurate assessment and premature termination of the procedure. The aim of this study is to compare paracetamol 325 mg/tramadol 37.5 mg with placebo in relieving pain before EMG. This is a randomized, crossover, placebo-controlled, double-blind clinical trial; forty-four healthy individuals, including 27 males with a mean age of 35.3 years (range 18–59 years), entered this study. The needles were inserted unilaterally 2 h after administration of two analgesic tablets of paracetamol 325 mg/tramadol 37.5 mg or two placebo tablets. The pain was scored through a 100-mm visual analog scale (VAS) immediately and 2 h after the procedure. The side effects were also recorded. Within a week, the procedure was repeated on the other upper limb, changing the treatment and placebo. The immediate and 2-h VAS scores were notably lower after administration of treatment compared to placebo (immediate pain: 17.5 ± 12.8 vs. 32.1 ± 16.0, P < 0.001; and 2-h pain: 1.6 ± 5.6 vs. 5.8 ± 7.9, P = 0. 002). There was a higher prevalence of side effects when treatment was used (48 vs. 9 %, P < 0.001). Although most symptoms were mild, transient and resolved without medical interventions, on one occasion a volunteer experienced brief loss of consciousness and one subject had severe vertigo that required hospitalization and fluid therapy. Paracetamol 325 mg/tramadol 37.5 mg administration prior to EMG could effectively alleviate pain. Further application of this medication in patients with neuromuscular disorders would warrant additional clinical trials, particularly considering the adverse events.