The potential beneficial effects of antihypertensive drugs on cardiovascular morbidity and mortality may be compromised by their adverse effects on serum lipid levels. In our study we compared verapamil and captopril and evaluated their effects on blood pressure and on serum lipid and lipoprotein levels, with particular attention to lipoprotein(a) [Lp(a)]. 20 hypertensive patients were treated with sustained release verapamil 240mg once daily or captopril 25mg twice daily for 3 months in a double-blind randomised study. Diastolic blood pressure was reduced from 100 +/- 3mm Hg to 87 +/- 6mm Hg (p < 0.01) and from 100 +/- 5mm Hg to 92 +/- 7mm Hg (p < 0.05) in the verapamil and captopril groups, respectively. Small but significant changes in serum lipid levels were noted: total cholesterol was reduced from 6 to 5.8 mmol/L (verapamil) and from 6.1 to 5.9 mmol/L (captopril); low density lipoprotein (LDL) cholesterol was reduced from 4 to 3.8 mmol/L (verapamil) and from 4.2 to 3.9 mmol/L (captopril); apolipoprotein C-III was reduced from 0.3 +/- 0.07 to 0.2 +/- 0.06 mmol/L (9.7 +/- 2.5 to 9.2 +/- 2.3 mg/dl) [verapamil] and from 0.2 +/- 0.1 to 0.2 +/- 0.09 mmol/L (9.1 +/- 3.7 to 8.3 +/- 3.4 mg/dl) [captopril]; apolipoprotein A-II increased only with verapamil (p < 0.02). Lp(a) levels showed only minor changes in individual patients. In conclusion, in our study verapamil and captopril were effective antihypertensive agents and did not adversely effect the lipid profile.