Table II.

Clinical Trials Evaluating Dual Calcium Channel Blocker Therapy in Angina

Reference	Disease and Number of Subjects	Study Design	Monotherapy (Mean Dosage)	Dosage of Dual Therapy	Results of Dual Therapy
Prida et al. 8	Coronary artery spasm n=9	R/P‐C; D‐B mono; O‐L dual, cross‐over	Diltiazem 90–360 mg/d; nifedipine 30–120 mg/d	Diltiazem 90–360 mg/d (206 mg/d); nifedipine 30–120 mg/d (61 mg/d)	Intolerable adverse effects in 33% (3/9); clinical improvement in 22% (2/9); no improvement in 44% (4/9)
Pucci et al. 9	Stable effort angina n=12	D‐B/P‐C; 4 × 4 400‐mg once daily Latin‐square	Diltiazem 60 mg × 1 and felodipine 10 mg × 1	Diltiazem 60 mg × 1 with felodipine 10 mg × 1	Prolongation of exercise time to ischemic threshold and to peak exercise; 1 patient with hypotension
Frishman et al. 10	Stable effort angina n=13	R/PL, D‐B mono; O‐L dual, cross‐over	Diltiazem 180–360 (352 mg/d) and nifedipine 30–120 mg/d (95 mg/d)	Diltiazem 180–360 (320 mg/d) and nifedipine 30–120 mg/d (52 mg/d)	Improved exercise tolerance and ↓ in angina attacks; ↑ nifedipine concentrations with dual therapy
Toyosaki et al. 11	Stable effort angina n=11	R/P‐C/D‐B, cross‐over	Diltiazem 120 mg/d and nifedipine 40 mg/d	Diltiazem 120 mg/d with nifedipine 40 mg/d	↑ exercise time; ↑ nifedipine concentrations with dual therapy
R=randomized; P‐C=placebo‐controlled; D‐B=double‐blind; O‐L=open‐label; PL=placebo Adapted with permission from Ann Pharmacother. 1996;30:802–810. 16