Evaluation of a drug-drug interaction: fax alert intervention program

Table 3 Counts of unique fax alerts sent and recommended therapy changes for intervention and control groups

*PDDI pair*	*Unique fax alerts sent*	*% of total PDDIs*	*Number of intervention group changes*	*Change rate (%)*	*Number of control group changes*	*Change rate (%)*	*p-Value*
Warfarin + Statins^a	939	46.5%	9	1.0%	10	1.1%	0.82
Statins + Azoles^b	247	12.2%	2	0.8%	2	0.8%	1.0
Warfarin + Fibrates^c	303	15.0%	55	18.2%	48	15.8%	0.45
Simvastatin + Amiodarone	169	8.4%	8	4.7%	3	1.8%	0.13
Statins + Macrolides^d	140	6.9%	41	29.3%	42	30.0%	0.89
Benzodiazepines + Azoles^e	86	4.3%	9	10.5%	4	4.7%	0.15
Warfarin + Azoles^e	62	3.1%	1	1.6%	1	1.6%	1.0
Ciprofloxacin + Tizanidine	24	1.2%	13	54.2%	11	45.8%	0.56
Isotretinoin + Tetracycline/Minocycline	15	0.7%	1	6.7%	1	6.7%	1.0
Amiodarone + Macrolides^f	11	0.5%	2	18.2%	4	36.4%	0.63
Theophylline + Quinolones^g	12	0.6%	8	66.7%	2	16.7%	0.04
Amiodarone + Quinolones^h	7	0.3%	3	42.9%	2	28.6%	1.0
Carbamazepine + Macrolidesⁱ	4	0.2%	2	50.0%	2	50.0%	1.0
Total	2019	100.0%	154	7.6%	132	6.5%	0.177

NA = not applicable to calculate recommended therapy modification using a pharmacy claims database; PDE5 = phosphodiesterase type 5.
^a warfarin + atorvastatin, lovastatin, or simvastatin.
^b atorvastatin, lovastatin, or simvastatin + itraconazole, ketoconazole, posaconazole, voriconazole, or fluconazole.
^c warfarin + fenofibrate or gemfibrozil.
^d atorvastatin, lovastatin, or simvastatin + erythromycin or clarithromycin.
^e warfarin + fluconazole, miconazole, or voriconazole.
^f amiodarone + clarithromycin or erythromycin.
^g theophylline + ciprofloxacin or norfloxacin.
^h amiodarone + gemifloxacin, levofloxacin, moxifloxacin, or ofloxacin.
ⁱ carbamazepine + erythromycin or clarithromycin.

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