Apparent elevation of serum CK-MB not due to acute myocardial infarction.

An increased serum level of the MB isoenzyme of creatine kinase (CK-MB) is a useful marker for acute myocardial infarction. Although described extensively in clinical chemistry literature, there is little information in standard medical references about false positives for this test. We report two cases where high levels of measured CK-MB activity were in fact due to another form of CK, associated with internal malignancy.

Atenolol and sustained release nifedipine alone and in combination in hypertension. A randomised, double-blind, crossover study.

In this randomised, double-blind, crossover trial, the efficacy in hypertension of atenolol and nifedipine as single agents or in combination was compared. 81 patients with mild to moderate essential hypertension (sitting diastolic blood pressure 100-120 mm Hg, aged 20-70 years) from 6 outpatient clinics entered the study. By use of a Latin-square design, patients received, in randomised fashion, sustained release nifedipine 20mg twice daily, atenolol 50mg in the morning and then placebo in the evening, or sustained release nifedipine 20mg plus atenolol 50mg in the morning and then placebo in the evening. Each schedule was followed for 4 weeks. All treatments lowered systolic and diastolic blood pressure in the supine and standing positions compared with pretreatment values. The combination regimen significantly reduced supine and standing systolic (p less than 0.01 and p less than 0.001, respectively) and diastolic (p less than 0.001) blood pressure compared with nifedipine alone, and it also significantly reduced supine and standing systolic (p less than 0.01 and p less than 0.03, respectively) and diastolic (p less than 0.01) blood pressure compared with atenolol alone. Heart rate was significantly decreased by atenolol and the combination compared with nifedipine alone. 15 patients withdrew because of side effects: 9 during nifedipine treatment, 2 during atenolol treatment and 4 during combination treatment. Side effects were typical of those associated with nifedipine or atenolol. Flushes and hot sweats, which were frequent with nifedipine, were significantly less (p less than 0.001) with atenolol or the combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the duration of antihypertensive action of atenolol and metoprolol over a 24-hour period.

The antihypertensive and beta-blocking effect of 100 mg atenolol and 100 mg metoprolol each given once daily were compared using an observer-blind, randomized, placebo-controlled crossover study. Blood pressure and heart rate were measured 22 hours after the last tablet of a 2-week dosing period. Twenty-five patients completed the study. Both drugs caused a significant decrease in supine and standing blood pressure, with atenolol effecting, numerically, the greater reductions. The decrease in standing diastolic blood pressure was significantly greater with atenolol than with metoprolol (p less than 0.05). Metoprolol at 22 hours post-dosing did not differ from placebo in the control of exercise systolic blood pressure (191.1 v 194.6 mmHg): the exercise systolic blood pressure achieved on atenolol (177.3 mmHg) was significantly lower than that achieved on both placebo (p less than 0.001) or metoprolol (p less than 0.05). The heart rates achieved on atenolol were significantly lower than those achieved on metoprolol in similar circumstances (p less than 0.001). It is concluded that, at the doses examined in this study, atenolol is the more suitable agent for the control of supine, standing and exercise blood pressure over 22 hours.