Table 2.

Side-effect profile

Study	Headache	Dyspepsia	Back pain	Myalgia
McMahon et al21	8.7% (10 mg)	8.7% (10 mg)	4.3% (10 mg)	0% (10 mg)
	13.6% (20 mg)	6.1% (20 mg)	4.5% (20 mg)	4.5% (20 mg)
	16.1% (on-demand)	9.8% (on-demand)	6.3% (on-demand)	4.5% (on-demand)
McMahon et al46	8.0% (10 mg daily)	10.7% (10 mg daily)	6.7% (10 mg daily)	4.0% (10 mg daily)
	17.1% (20 mg as-needed)	12.9% (20 mg as-needed)	4.3% (20 mg as-needed)	4.3% (20 mg as-needed)
Porst et al42	6.4% (5 mg)	5.5% (5 mg)	3.7% (5 mg)	2.8% (5 mg)
	10.5% (10 mg)	11.4% (10 mg)	9.5% (10 mg)	6.7% (10 mg)
	7.4% (placebo)	3.7% (placebo)	3.7% (placebo)	0.0% (placebo)
Rajfer et al47	3.1% (2.5 mg)	4.2% (2.5 mg)	5.2% (2.5 mg)	4.2% (2.5 mg)
	1.0% (5 mg)	1.0% (5 mg)	2.1% (5 mg)	1.0% (5 mg)
	3.2% (placebo)	1.1% (placebo)	3.2% (placebo)	2.1% (placebo)
Hellstrom et al55	16% (20 mg)	8% (20 mg)	11% (20 mg)	8% (20 mg)
	2% (placebo)	1% (placebo)	3% (placebo)	1% (placebo)
Donatucci et al43
1-y extension phase	9%	9%	7%	–
2-y extension phase	2%	4%	5%	–
Porst et al48
1-y extension phase	9.0%	9.0%	6.8%	–
2-y extension phase	2.1%	3.8%	5.0%	–
Porst et al50	3.5% (2.5 mg)	0.9% (2.5 mg)	1.8% (2.5 mg)	1.8% (2.5 mg)
	3.4% (5 mg)	4.3% (5 mg)	0.9% (5 mg)	0.9% (5 mg)
	5.0% (10 mg)	1.7% (10 mg)	4.2% (10 mg)	3.3% (10 mg)
	1.7% (20 mg)	2.6% (20 mg)	5.2% (20 mg)	2.6% (20 mg)
	3.5% (placebo)	0% (placebo)	0.9% (placebo)	0% (placebo)