Effects of Pharmacist Interventions on Pain Intensity: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Effects of Pharmacist Interventions on Pain Intensity: Systematic Review and Meta-Analysis of Randomized Controlled Trials
McKenzie Pfeffer, PharmD, St. Cloud VA

Background: Pain plays a significant role in the lives of many individuals. It is associated with a high rate of disability and disease burden and can also have a substantial impact on quality of life. Patients experiencing chronic pain may not only notice physical limitations, but may also see an impact on several areas of daily life such as poor sleep quality, inability to accomplish daily tasks, and mental health challenges. Over 100 million adults in the United States have chronic pain, which contributes to staggering costs up to 635 billion dollars per year to the US healthcare system. Pharmacists continue to be one of the most accessible health care professionals. As a result, pharmacists providing clinical services not only increase access to care, but may also contribute to improved outcomes in overall functioning and reduction in pain. Prior to this review, comprehensive assessment of pharmacist interventions on pain intensity was limited.

Purpose: The aim of this systematic review and meta-analysis was to assess current literature on the effect of any type of pharmacist intervention, whether led by a pharmacist or in a supportive role, on pain intensity over time in patients with any type of pain.

Study Design: Electronic databases including MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from inception until May 2021. Several search terms were pharmacy, pain, and randomized controlled trial. Randomized controlled trials (RCTs) and clinical trials were screened by two reviewers independently. Each trial required a control group who received usual care. Pain types, pharmacist intervention types, settings, and pain assessment tools varied. The outcome of interest was a reduction in pain intensity. Data was pooled using a random-effects model. Results were presented as standardized mean differences (SMD) and their 95% confidence interval (CI). Subgroup analyses were performed based on pain etiology.

Results: Upon reviewing 1478 records through the database search, 12 studies were eligible for inclusion. Within the 12 studies, a total of 1710 participants were identified, over 60% of whom were female. Study locations were across the world, including the United States (n= 2), and most were based in a community pharmacy setting (n=4). Other settings included community clinics (n= 3), hospitals (n=3) or specialized outpatient settings such as pain clinics (n=3). Pain etiologies included originating from the musculoskeletal and neurologic systems, cancer-related pain, postoperative pain, and chronic pain. Pharmacist interventions ranged from medication reviews, patient education (e.g. counseling), dosage adjustments, and nonprescription medication recommendations. Results of the pooled estimates of the studies revealed a statistically significant reduction in pain intensity compared with controls (SMD -0.22 [95% CI -0.31 to -0.12]). Educational interventions alone were not found to be statistically significant in reduction in pain intensity. Subgroup analyses based on pain type showed pharmacist intervention was effective in reducing pain intensity for patients with chronic pain (SMD -0.26 [95% CI -0.37 to -0.14) but no reduction in pain intensity for patients with acute pain (SMD -0.14 [95% CI -0.40 to 0.12]). Subgroup analyses showed that pharmacist interventions at outpatient clinics and hospitals were effective, but not in community pharmacy settings.

Conclusion: While there were several limitations, including small sample size and variability in pharmacist interventions and settings, findings from this systematic review and meta-analysis showed that pharmacists in both community clinic and hospital settings may play an important role in reducing pain intensity in patients with pain of different etiologies. However, further high quality studies are needed to determine clinical significance.

Key Point: Pharmacists are well-positioned within the healthcare team to provide education and patient care for patients with pain from various etiologies. These interventions have the potential to reduce pain intensity and improve patient outcomes and quality of life.


  1. Duenas M, Ojeda B, Salazar A, Mico JA, Failed I. A review of chronic pain impact on patients, their social environment and the health care system. J Pain Res. 2016;9:457-467. doi:10.2147/JPR.S105892.
  2. Veettil SK, Darouiche G, Sawangjit R, Cox N, Ming Lai N, Chaiyakunapruk N. Effects of pharmacist interventions on pain intensity: systematic review and meta-analysis of randomized controlled trials. J Am Pharm Assoc. 2022(25:S1544-3191(22). Doi:10.1016/j.japh.2022.02.015.