Table 5.

Food and Drug Administration-approved pharmacological strategies

Intervention	Design and sample	Scales used	Mechanism of action	Effect on fatigue
Duloxetine	3 double blind, placebo-controlled RCTs of patients with FM (n = 899) [88-90]	MFI	Blocks reuptake of serotonin and norepinephrine within the central nervous system	Clinically meaningful improvement in 2 of the RCTs, no clinically meaningful improvement in the other
		FIQ fatigue
Milnacipran	6 double-blind, placebo-controlled RCTs of patients with FM (n = 4,243) [91-96]	MFI	Blocks reuptake of serotonin and norepinephrine within the central nervous system	No clinically meaningful improvement in 4 RCTs using MFI, cannot draw conclusion in 2 RCTs, and clinically meaningful improvement in 1 RCT (VAS fatigue)
	1 double-blind, dose finding trial (n = 468) [97]	VAS fatigue
Pregabalin	3 double-blind, placebo-controlled RCTs of patients with FM (n = 2,328) [98-100]	MAF	Interacts with the alpha-2-delta subunit of l-type voltage-regulated calcium channels	No clinically meaningful improvement in 2 RCTs, cannot draw conclusion in 1 RCT

FIQ, Fibromyalgia Impact Questionnaire; FM, fibromyalgia; MAF, Multidimensional Assessment of Fatigue; MFI, Multidimensional Fatigue Inventory; RCT, randomized controlled trial; VAS, Visual Analogue Scale.