The impact of medication side effects on functional outcomes among patients with chronic musculoskeletal pain

The primary purpose of the present study was to examine the potential impact of medication side effects (MSE) on functional outcomes among patients with chronic pain. In this study, a sample of 103 patients (52 women, 51 men) with chronic musculoskeletal pain being prescribed analgesic medications were asked to report the presence of any side effects (e.g., dizziness, nausea) that may be associated with their medication, and to rate the intensity of each side effect on a visual analog scale (VAS). Patients were also asked to complete self-report measures of pain intensity, negative affect (NA), daily functioning, and ability to work. For purposes of our study, a medication side effect index (MSE-I) was computed by summing, for each patient, the intensity of each side effect being experienced. Results of correlational analyses indicated that higher scores on the MSE-I were associated with lower scores on measures of daily functioning and ability to work (both p’s < .05). Interestingly, results of a follow-up direct multiple regression analysis revealed that medication side effects (MSE-I) were associated with decreased daily functioning even when controlling for patients’ sex, pain severity, and negative affect (NA) (p < .01). In this regression analysis, pain severity, NA, and medication side effects all emerged as significant unique (i.e., independent) predictors of patients’ daily functioning. Taken together, results from our study suggest that patients’ pain intensity, NA, and medication side effects might represent additive risk factors for poor functional outcomes among patients with chronic pain. The implications of our findings for the management of patients with chronic pain conditions will be discussed.