Pharmacy Students’ Retention of Knowledge of Drug-Drug Interactions

Article Figures & Data

Table 1.

Pharmacy Students’ Scores on a DDI Recognition Assessment

Object Drug	Precipitant Drug	Correct Answer for DR Scores	Correct Response % Baseline	Correct Response % Posttest	Correct Response % 1-Year	Absolute Difference in Scores Between:
Object Drug	Precipitant Drug	Correct Answer for DR Scores	Correct Response % Baseline	Correct Response % Posttest	Correct Response % 1-Year	Baseline and Posttest	Post and 1-Year	Baseline and 1-Year
Nitroglycerine	Sildenafil	I	97	100	100	+3	0	+3
Warfarin	Sulfamethoxazole/trimethoprim	I	94	97	97	+3	0	+3
Acetaminophen/codeine	Amoxicillin	NI	91	100	100	+9	0	+9
Warfarin	Naproxen	I	82	100	97	+18	−3	+15
Warfarin	Amiodarone	I	76	100	88	+24	−12	+12
Warfarin	Fluconazole	I	76	97	82	+21	−15	+6
Digoxin	Amiodarone	I	76	88	94	+12	+6	+18
Carbamazepine	Clarithromycin	I	65	97	94	+32	−3	+29
Warfarin	Gemfibrozil	I	59	97	71	+38	−26	+12
Simvastatin	Itraconazole	I	56	97	91	+41	−6	+35
Digoxin	Itraconazole	I	56	91	88	+35	−3	+32
Digoxin	Clarithromycin	I	53	97	79	+44	−18	+26
Digoxin	Sildenafil	NI	44	91	100	+47	+9	+56
Metformin	Erythromycin	NI	38	88	97^d	+50	+9	+59
Warfarin	Digoxin	NI	9	79	88	+70	+9	+79

Table 2.

Pharmacy Students’ Scores on an Assessment of DDI Management Strategy

Object Drug	Precipitant Drug	Correct Answer for MS Scores	Correct Response, % Baseline	Correct Response, % Post Test	Correct Response, % 1-Year	Absolute Difference in Scores Between:
Object Drug	Precipitant Drug	Correct Answer for MS Scores	Correct Response, % Baseline	Correct Response, % Post Test	Correct Response, % 1-Year	Baseline and Post	Post and 1-Year	Baseline and 1-Year
Nitroglycerine	Sildenafil	AC	94	100	100	+6	0	+6
Warfarin	Sulfamethoxazole/trimethoprim	UAC	26	88	56	+62	−32	+30
Acetaminophen/codeine	Amoxicillin	NI	91	100	100	+9	0	+9
Warfarin	Naproxen	UAC	24	91	38	+67	−53	+14
Warfarin	Amiodarone	TP	50	68	59	+18	−9	+9
Warfarin	Fluconazole	UAC	32	91	41	+59	−50	+9
Digoxin	Amiodarone	TP	21	82	44	+61	−38	+23
Carbamazepine	Clarithromycin	TP	50	85	41	+35	−44	−9
Warfarin	Gemfibrozil	UAC	18	91	32	+73	−59	+14
Simvastatin	Itraconazole	UAC	24	68	53	+44	−15	+29
Digoxin	Itraconazole	TP	29	74	41	+45	−33	+12
Digoxin	Clarithromycin	TP	29	91	53	+62	−38	+24
Digoxin	Sildenafil	NI	44	91	59	+47	−32	+15
Metformin	Erythromycin	NI	38	88	59	+50	−29	+21
Warfarin	Digoxin	NI	9	79	44	+70	−35	+35

Abbreviations: MS = DDI Management Strategy; AC = Avoid Combination; UAC = Usually Avoid Combination; TP = Take Precautions; NI = No Interaction.

Table 3.

Comparison of Drug-Drug Interaction Knowledge Between Students Who Presented at Least One DDI Vignette and Those Who Did Not Complete Any

Case Presented	Correct DR (%) CV (n = 18)	Correct DR (%) No CV (n = 16)	P	Correct MS (%) CV (n = 18)	Correct MS (%) No CV n = 16	P
Nitroglycerine + sildenafil	18 (100)	16 (100)	N/A	18 (100)	16 (100)	N/A
Warfarin + sulfamethoxazole/trimethoprim	18 (100)	15 (94)	0.28	12 (67)	7 (44)	0.19
Warfarin + naproxen	17 (94)	16 (100)	0.34	4 (22)	9 (56)	0.045
Warfarin + amiodarone	16 (89)	14 (88)	0.90	10 (56)	10 (63)	0.69
Warfarin + fluconazole	15 (83)	13 (81)	0.88	9 (50)	5 (31)	0.28
Digoxin + amiodarone	17 (94)	15 (94)	0.94	9 (50)	6 (38)	0.47
Carbamazepine + clarithromycin	17 (94)	15 (94)	0.94	8 (44)	6 (38)	0.69
Warfarin + gemfibrozil	15 (83)	9 (56)	0.80	8 (44)	3 (19)	0.11
Simvastatin + itraconazole	17 (94)	14 (88)	0.48	13 (72)	5 (31)	0.021
Digoxin + itraconazole	16 (89)	14 (88)	0.90	8 (44)	6 (38)	0.69
Digoxin + clarithromycin	15 (83)	12 (75)	0.55	11 (61)	7 (44)	0.31

Abbreviations : DR = DDI Recognition; MS = DDI Management Strategy; CV = Case Vignette

Table 4.

Vignette Presentation Characteristics

Characteristic	No. (%), N = 141
Health Care
Professionals Attending
Pharmacists	119 (84)
Others	55 (39)
Physicians	18 (13)
Nurse Practitioners	4 (3)
Setting
Hospital acute care	53 (38)
Community pharmacy	33 (23)
Other	16 (11)
Ambulatory care pharmacy	14 (10)
Hospital pharmacy	13 (9)
Community health center	6 (4)
Managed care	3 (2)
Office-based practice (group)	3 (2)
Subject of Vignette
Warfarin + sulfamethoxazole/trimethoprim	24 (17)
Warfarin + fluconazole	22 (16)
Warfarin + amiodarone	18 (13)
Simvastatin + itraconazole	17 (12)
Warfarin + naproxen	16 (11)
Carbamazepine + clarithromycin	15 (11)
Warfarin + gemfibrozil	9 (6)
Nitroglycerine + sildenafil	8 (6)
Digoxin + amiodarone	7 (5)
Digoxin + clarithromycin	3 (2)
Digoxin + itraconazole	2 (1)