Background: Corticosteroid injections have been used in carpal tunnel syndrome (CTS). However, there have been reported side effects associated with the drugs. Dexamethasone sodium phosphate has been studied to cause fewer side effects and the least neurotoxic agent. However, evidence of the efficacy of dexamethasone sodium phosphate in CTS is still lacking.

Objective: To compare the efficacy of dexamethasone sodium phosphate and triamcinolone acetonide in the treatment of CTS and observe their complications.

Materials and Methods: A prospective randomized double-blind controlled trial study was performed between January and December 2015 at HRH Princess Maha Chakri Sirindhorn Medical Center, Srinakharinwirot University in Nakhon Nayok province. Patients with CTS were randomly assigned into two groups based on the mode of treatment with either dexamethasone sodium phosphate or triamcinolone acetonide. Results of treatment were measured via hand grip power, positive Phalen’s test time, Global Symptom Score for Carpal Tunnel Syndrome (GSS), Disability of Arm, Shoulder, and Hand Questionnaire (DASH) score. Negative outcome in patients that required surgery and the complications were also recorded.

Results: Sixty patients with CTS were randomly assigned into two groups [dexamethasone sodium phosphate group (n = 30) and triamcinolone acetonide group (n = 30)]. There was no difference of demographic data between the two groups. The dexamethasone sodium phosphate group improved significantly in positive Phalen’s test time (mean difference -5.53; 95% confidence interval -0.56 to -10.50, p=0.029). In other measurement, the dexamethasone sodium phosphate group had better scores and had a lower number of patients who required and underwent surgery, but there was no significant difference between the two groups (p>0.05). No serious complication was detected at the time of follow-up.

Conclusion: In the treatment of CTS by corticosteroid injection, dexamethasone sodium phosphate was effective and improved significantly in positive Phalen’s test time, compared to those treated with triamcinolone acetonide, which was widely prescribed.

No serious complication was detected in either groups.