Effect of silymarin topical gel compared to placebo topical gel as adjunctive therapy on pain control after stroke: a double-blind randomized clinical trial

To assess the effect of silymarin topical gel compared to placebo topical gel as adjunctive therapy on pain control after stroke

This is a Phase III double-blind randomized clinical trial with a control group with parallel groups, in which eligible patients will be randomly assigned to the intervention and control groups using block randomization.

This study will be conducted at the Besat Hospital in Hamadan city, involving 25 eligible patients with stroke. The patients will be randomly assigned to the intervention and control groups through the block randomization. This trial will be double-blinded.

Inclusion criteria: Age 18 to 75 years; Stroke; Shoulder and scapula muscle pain and stiffness; Exclusion criteria: Pregnancy or breastfeeding; Kidney or liver failure; Use of painkillers; Substance abuse

Intervention group: Standard treatment included pregabalin tablets 50 to 75 mg twice daily and duloxetine tablets 20 mg twice daily for 3 months plus 3% silymarin topical gel on the shoulder and scapula area twice daily for 3 months Control group: Standard treatment included pregabalin tablets 50 to 75 mg twice daily and duloxetine tablets 20 mg twice daily for 3 months plus placebo topical gel on the shoulder and scapula area twice daily for 3 months

Primary outcome: Mean pain score; Mean quality of life score; Degree and frequency of muscle cramps Secondary outcome: Local complications (redness, burning, itching)

In this study, random assignment of patients to the intervention and control groups will be carried out using block randomization. To achieve this, four sheets of paper will be prepared - two with the name of the intervention and two with the name of the control. These paper sheets will be pooled and placed in a container. Patients will be selected one at a time without replacement, and for each patient, a paper sheet will be randomly drawn from the container. After each draw, the paper sheets will be returned to the container, and the process will be repeated until the desired sample size is reached.

Both the medications and placebos will have the same shape. Consequently, patients will remain unaware of the type of intervention they receive. Moreover, the randomization process will be conducted by a separate individual from the one who examines the patients, ensuring that the examining person remains unaware of the intervention. Therefore, the trial will be conducted as a double-blind study.