Weight Change with Long-term Duloxetine Use in Chronic Painful Conditions

P. Gaynor; B. McCarberg; W. Zheng; S. Shoemaker; H. Duenas


Int J Clin Pract. 2011;65(3):341-349. 

In This Article

Abstract and Introduction


Aims: Report weight change baseline up to 12–15 months in duloxetine-treated patients during clinical trials of chronic painful conditions of diabetic peripheral neuropathic pain (DPNP), fibromyalgia, chronic low back pain (CLBP) and chronic knee pain as a result of osteoarthritis.
Methods: Weight change data from 16 duloxetine studies in chronic painful conditions were pooled by pain condition and duration, creating 10 datasets. Datasets included placebo-controlled, open-label and routine-care-controlled designs. Assessments included mean weight change from baseline, baseline body mass index category, potentially clinically significant (PCS) weight change and weight-related treatment-emergent adverse events.
Results: Total number of patients was 5111 with mean baseline weight ranging from 70 to 97 kg. All duloxetine groups had significant mean weight loss compared with placebo at acute phase completion (p ≤ 0.001). In studies > 3 months, patients from fibromyalgia and CLBP studies had overall mean weight increase (up to 1.1 kg), whereas patients in DPNP studies had overall mean weight loss (−0.33 to −1.7 kg) at end-point. Overall, the percentage of patients with PCS weight gain was 0.4–16% and PCS weight loss was 2.5–9.9%.
Discussion: Weight change data in clinical trials of patients with fibromyalgia or CLBP treated with duloxetine for up to 15 months were consistent with data reported in 10 clinical trials of patients with major depressive disorder (MDD) using duloxetine up to 52 weeks. Patients with DPNP had weight loss at end-point.
Conclusion: Mean weight changes and percentages of patients with PCS weight loss and weight gain observed in DPNP, fibromyalgia and CLBP with long-term duloxetine treatment were consistent with those reported previously for MDD studies.


Body weight may be affected by numerous factors, including age, presence of disease and personal health behaviour. Chronic pain may interfere with daily activities, mobility, activity level and appetite, which in turn may contribute to changes in weight.[1] The International Association of the Study of Pain (IASP) reports that one in five adults have chronic pain, and between one-half and two-thirds of those reporting chronic pain are unable to perform everyday activities, including exercise.[2] According to Wright and associates, the state of being overweight or obese has been consistently associated with some chronic painful conditions, including fibromyalgia and low-back pain.[3] There are data to suggest that some medications, including antidepressants, antiglycaemics, antiepileptics, as well as some used to treat chronic painful conditions such as fibromyalgia and diabetic peripheral neuropathic pain (DPNP), may contribute to unintentional change in body weight.[4–6] Change in body weight, particularly weight increase, may affect a patient's willingness to try and/or adhere to a particular therapy and it has been suggested that clinicians should consider this possibility when developing a therapeutic regimen.[4]

The effect of medication on body weight is one consideration that a practitioner may evaluate when choosing a particular therapy. Duloxetine hydrochloride is a serotonin and norepinephrine reuptake inhibitor approved in the United States for the treatment of major depressive disorder (MDD), generalised anxiety disorder, management of DPNP, fibromyalgia and chronic musculoskeletal pain as established in chronic low back pain and chronic pain due to osteoarthritis.[7] Although weight change in duloxetine-treated patients in MDD studies has been reported, data on long-term weight change in duloxetine-treated patients with chronic painful conditions are limited. In an analysis of 10 acute and long-term duloxetine clinical trials in patients with MDD, Wise et al. reported that duloxetine-treated patients had statistically significant mean weight loss (kg) compared with placebo (p < 0.001).[8] At end-point, significantly more duloxetine – compared with placebo-treated patients in the acute MDD studies experienced potentially clinically significant (PCS) weight loss (p = 0.035), and although not statistically significant, fewer patients experienced PCS weight gain (p = 0.103). In the long-term MDD studies, duloxetine-treated patients experienced weight gain [significant weight gain at end-point in the comparator-controlled study (p ≤ 0.05) and the non-placebo-controlled study (p ≤ 0.001), and non-statistically significant weight gain in the placebo-controlled trial]. Significantly more duloxetine-treated patients in the long-term MDD studies experienced PCS weight gain at end-point. The authors suggested that, overall, there seemed to be a pattern of acute weight loss with duloxetine, followed by weight gain after longer term treatment, and concluded that duloxetine may be an acceptable option when effects on weight are a consideration of a medication to treat depression.[8] The primary objective of this analysis was to report weight change in studies with durations up to 12–15 months in patients taking duloxetine for chronic painful conditions including DPNP, fibromyalgia, chronic low back pain (CLBP) and osteoarthritis (OA).


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