Table 2. Cross-matching the national DDI rules with the list of high-priority DDI rules.

Rule No.*	List of high-priority DDI rules			National DDI rules
	Object drug/class	Precipitant drug/class	No. of final pairs	No. of matched rules	No. of unmatched national rules
3	Amphetamine and derivatives	MAO inhibitors	60	6	54
4	Atazanavir	PPI	5	4	1
5	Febuxostat	Azathioprine/mercaptopurine	2	0	2
8	SSRIs	MAO inhibitors	55	4	51
11	Irinotecan	Strong CYP3A4 inhibitors	24	1	23
16	Narcotic analgesics	MAO inhibitors	30	3	27
20	TCAs†	MAO inhibitors	40	5	35
21	QT-prolonging agents‡	QT-prolonging agents‡	2,162	17	2,145
22	Ramelteon	CYP1A2 inhibitors	4	0	4
23	Strong CYP3A4 inhibitors	Protease inhibitors	60	2	58
25	HMG Co-A reductase inhibitors	CYP3A4 inhibitors	38	12	26
27	CYP3A4 inhibitors	Ergot alkaloids and derivatives	60	22	38
28	Tizanidine	CYP1A2 inhibitors	7	1	6
30	Tranylcypromine	Procarbazine	1	0	1
31	Triptans	MAO inhibitors	15	1	14
	No. of class-pairs: 15 (100.0%)			No. of matched class-pairs 12 (80.0%)
	No. of drug-pairs: 2,563 (100.0%)			No. of matched drug-pairs 78 (3.0%)

DDI = drug-drug interaction, PPI = proton-pump inhibitors, SSRI = selective serotonin reuptake inhibitors, MAO = monoamine oxidase, TCAs = tricyclic antidepressants.

^*Rule number in (13); ^†List of TCAs: Mayo Clinic, http://www.mayoclinic.org/diseases-conditions/depression/in-depth/antidepressants/art-20046983?pg=2; ^‡QT-prolonging agents: https://www.crediblemeds.org (accessed May 15, 2015).