Analysis of Real World Dosing Patterns for the 3 FDA-Approved Medications in the Treatment of Fibromyalgia

BACKGROUND: Fibromyalgia is a chronic condition characterized by widespread pain, fatigue, and sleep disturbances that affects approximately 2% to 4% of the adult population in the United States, with minimal real-world data related to the use of medications and associated dosages for this condition. OBJECTIVE: To analyze the real-world dosing patterns of the 3 medications approved by the US Food and Drug Administration for fibromyalgia-pregabalin, duloxetine, and milnacipran. METHODS: Using QuintilesIMS' (now IQVIA) electronic medical record data linked to administrative claims, we identified adults with fibromyalgia who were newly prescribed pregabalin, duloxetine, or milnacipran between January 1, 2006, and December 31, 2014. We summarized and compared the starting and maximum doses with United States prescribing information (USPI) dosing recommendations. RESULTS: In all, 1043 patients who were receiving pregabalin, 1281 receiving duloxetine, and 326 patients receiving milnacipran with similar age and comorbidity profiles were included in the study. The mean starting dose was 176 mg daily, 56 mg daily, and 95 mg daily for pregabalin, duloxetine, and milnacipran, respectively. More patients receiving pregabalin (35%) had a starting dose lower than recommended compared with patients receiving duloxetine (7%) or milnacipran (17%; P<.0001). Of the patients who received pregabalin, 27% had USPI-recommended maintenance dosing versus 91% of patients who received duloxetine and 80% who received milnacipran (P<.0001). The mean duration of treatment was longer for duloxetine (205 days; P<.0001) than for pregabalin (167 days) and milnacipran (167 days). The duration of using the maximum dose of each medication as a percentage of the total time of medication use was 77% for pregabalin, 84% for duloxetine, and 90% for milnacipran (P<.0001). CONCLUSIONS: Patients using pregabalin were the most likely of the 3 cohorts to receive lower than label-recommended starting doses and the least likely to receive the recommended maintenance doses during follow-up compared with those receiving duloxetine or milnacipran. Real-world prescribing patterns indicate that factors other than label recommendations may be influencing prescribed dosing.