Table 5.

Analysis of potential DDIs in accordance with the Food and Drug Administration recommendations. Critical interactions exceeding the cutoff of R ≥ 1.1 are highlighted in bold

		Perpetrator
		Fenoterol	Sumatriptan	Ipratropium	Trospium	Metformin	Quinidine	Verapamil	Trimethoprim
Victim drug	Fenoterol		1.00	1.00	1.00	1.00	1.17	1.18	1.19
	Salbutamol	1.00	1.00	1.00	1.01	1.00	1.45	1.53	1.23
	Sumatriptan	1.00		1.00	1.00	1.01	1.11	1.09	1.71
	Zolmitriptan	1.00	1.00	1.00	1.01	1.00	1.32	1.60	1.24
	Ipratropium	1.00	1.01		1.01	1.01	1.10	1.09	1.79
	Trospium	1.00	1.01	1.00		1.00	1.15	1.13	1.46
	Methylnaltrexone	1.00	1.00	1.00	1.01	1.01	1.32	1.29	1.45
	Metformin	1.00	1.00	1.00	1.01		1.25	1.30	1.20

DDI, drug-drug interaction; R, drug drug interaction risk.