Royal Hallamshire Hospital, Sheffield S10 2JF1 The pharmacokinetics and pharmacodynamics of oral verapamil and propranolol were studied in patients with stable angina pectoris during chronic mono-and dual therapy. 2 The peak plasma concentrations (Cmax) and areas under the plasma concentrationtime curves (AUC) of verapamil were similar during combined treatment with propranolol (mean ± s.d.: Cmax = 491 ± 397 ng ml-'; AUC = 2075 ± 1524 ng ml-' h) or atenolol (mean + s.d.: Cmax = 372 ± 320 ng ml-'; AUC = 1985 ± 1660 ng ml-' h).3 No differences in Cmax and AUC were observed during verapamil monotherapy (mean + s.d.: Cmax = 287 ± 105 ng ml-'; AUC = 1375 ± 455 ng ml-' h) vs combined treatment with propranolol (mean ± s.d.: Cmax = 312 ± 55 ng ml-'; AUC = 1566 ± 486 ng ml-' h).4 Treatment with verapamil increased the Cmax (mean ± s.d.: 227 ± 117 vs 116 ± 62 ng ml-', P < 0.05) and AUC (1389 ± 617 vs 837 ± 316 ng ml-' h, P = 0.0625) of propranolol in all subjects. 5 Transient atrioventricular dissociation occurred in two patients 2 h after dosing with verapamil and propranolol or atenolol.6 Close observation of patients is essential when 13-adrenoceptor antagonists and verapamil are used together.