Complex regional pain syndrome (CRPS) is a disabling pain condition, which is distinct from other pain syndromes by the presence of autonomic dysfunction and regional inflammatory changes. To explore the impact of pharmacological treatment strategies, specifically scheduled, on-demand dosing regimens versus lack of medical treatment, on pain-related and functional outcomes in rehabilitation for individuals with CRPS. A total of 32 participants with CRPS were assigned to three treatment groups depending on analgesic treatment during the course of complex rehabilitation. Pre- and post-rehabilitation assessments were conducted using validated measures, including the Numerical Rating Scale (NRS) for pain, the Short-Form McGill Pain Questionnaire (SF-MPQ), PainDETECT, the Disabilities of the Arm, Shoulder, and Hand (DASH), and the Lower Extremity Functional Scale (LEFS). Significant improvements in pain and upper limb function (DASH scores) were observed across all groups ( < 0.05). No statistically significant changes were found in lower limb function (LEFS). Between-group comparisons revealed significant differences in post-treatment pain scores (SFMPQ-B), particularly between groups with a constant treatment regimen and those without treatment. There were no statistically significant changes compared to different treatment regimen groups. The constant treatment group showed slightly better average improvements in pain and disability compared to other groups. Statistically significant improvements in all CRPS patients were observed in pain-related and functional measures.