Vasospastic phenomena in patients treated with beta-adrenoceptor blocking agents

Twenty-one patients developed Raynaud's phenomenon during treatment with beta-adrenoceptor blocking agents. The vasospastic symptoms were obviously related to the treatment, but their pathogenesis is still controversial. A decrease in cardiac output might explain the phenomenon. According to our very preliminary data an alpha-adrenergic dominance caused by a direct effect on the peripheral circulation seems more probable. Vasospastic symptoms may arise after treatment with both cardioselective and non-selective beta blocking agents. Cautious prescription of beta blocking drugs to patients with preexisting peripheral vascular disease is recommended.

Acute intervention with metoprolol in myocardial infarction

Studies in experimental and clinical myocardial infarction support the idea that sympathetic activity and myocardial noradrenaline release play a significant role in the development of myocardial ischemic damage. Betablockade has been shown to limit infarct size and lower the incidence of ventricular fibrillation in experimental models. Betablockade to patients (pts) with acute myocardial infarction (AMI) has been shown to reduce ischemia reflected as reduction of ischemic chest pain, decrease ST-segment elevation and increase lactate extraction. Whether this treatment in the clinical situation can prevent development of infarction, reduce infarct size and early mortality in man remains to be proven. In Gøteborg a double-blind study on metoprolol and placebo was started four and a half years ago. Inclusion of pts. in the study has been terminated and survival data will be available on May 1, 1981. 1395 pts. were included of whom 800 developed AMI. Metoprolol 15 mg was given IV followed by a total daily dose of 200 mg/day. The tolerance for betablockade was generally good. Analysis of serum enzyme estimations of maximal LD I + II showed a significant reduction by metoprolol when the treatment was given within 12 hours of onset of pain. In a subgroup consisting of 103 pts. with AMI metoprolol had no clearcut effects on the ventricular arrhythmias during the first 24 hours in hospital. The betablockade resulted in a 15% reduction in heart rate. The main objective of this study, the mortality during three months of blind treatment will be published late in 1981.

Antihypertensive effects at rest and during exercise of a calcium blocker, nifedipine, alone and in combination with metoprolol

The effects of metoprolol and/or nifedipine on blood pressure were studied in 12 hypertensive males at rest and during standardized exercise on an ergometer bicycle. Metoprolol (100 mg X 2) and nifedipine (10 mg X 3) gave similar blood pressure reductions both at rest and during exercise. When the drugs were combined, the antihypertensive effect was potentiated. The PQ interval was not affected during any treatment period. No adverse reactions to the combined treatment were noted. The combination of a calcium blocker with vasodilating properties with a beta-blocker, which reduces cardiac output, thus seems a logical and promising therapeutic approach in the treatment of hypertension.

Ventricular dysrhythmias in middle-aged hypertensive men treated either with a diuretic agent or a beta-blocker

The purpose of this study was to identify the frequency of cardiac dysrhythmias in two similar groups of hypertensive middle-aged males (age 45-66). They had previously been randomized either to a diuretic treatment (n = 42), or a beta-blocking agent (n = 41). A 24-hour ambulatory Holter monitoring, and serum potassium, was obtained in all patients, serum magnesium was measured in 35 patients. The mean number of ventricular premature beats (VPBs) and the frequency of complex arrhythmias (19 vs. 5) was significantly higher in the diuretic group (p less than 0.01). The serum potassium was significantly lower (p less than 0.001) in the diuretic group, and there was a significant (p less than 0.005) inverse correlation between the number of VPBs and the serum potassium in all treated patients. The patients with complex arrhythmias were older (p less than 0.01) than the remainder of the patients. No correlation between serum magnesium and VPBs or complex arrhythmias was found. This study demonstrates increased frequency of VPBs in older hypertensive males, treated with diuretics, and that hypokalaemia predisposes to increased cardiac arrhythmias. We conclude that in older mildly hypertensive men hypokalaemia should be avoided.

Established beta-adrenergic receptor blocking therapy and acute myocardial infarction. A clinical study of risks and benefits

In order to evaluate the risks and benefits of continuing established therapy with beta-adrenergic receptor blocking drugs during acute myocardial infarction (AMI), 183 consecutive patients, 63 with (beta-blocker group) and 120 without (control group) this therapy, were studied. Detailed information on previous diseases, present symptoms, established medication, clinical and laboratory findings on admission and during the first 12 hours in the CCU was collected. The incidences of congestive heart failure, hypotension, AV blocks and ventricular arrhythmias were not significantly more common in the control group (8 vs. 28%, p less than 0.01). Thus, continuation of established therapy with beta-adrenergic receptor blocking drugs does not seem to increase the risk of complications after hospital admission for AMI. The reason for the low incidence of inferior wall infarction in the beta-blocker group is not clear but it cannot be excluded that when patients on beta-adrenergic receptor blocking therapy develop an inferior AMI, they may run a greater risk of sudden death.

Tolerability to treatment with metoprolol in acute myocardial infarction in relation to age

A double-blind trial with the beta 1-selective blocker metoprolol in suspected acute myocardial infarction and during 3 months' follow-up included 1395 patients, aged 40-74 years, 698 on metoprolol and 697 on placebo. In order to further evaluate the tolerability to beta-blockade in the elderly, the total series was divided into 2 groups according to median age (61 years) and into quartiles, the lowest quartile (40-57 years) being compared with the highest (67-74 years). The decrease in heart rate and systolic blood pressure after intravenous metoprolol in the acute phase was similar in the elderly and the younger patients. Hypotension was observed more often in the metoprolol-treated than in the placebo-treated younger patients, while no difference was observed in the elderly. Bradycardia was observed more often in the metoprolol group in both age groups, while there was no difference regarding the incidence of congestive heart failure in either the younger or in the elderly patients. The effect on mortality, serious ventricular arrhythmias and chest pain seemed to be similar in different age groups. From the present series we conclude that hemodynamic reactions and tolerability to beta-blockade can be expected to be similar in elderly and younger patients.

Peripheral vasospasm during beta-receptor blockade - a comparison between metoprolol and pindolol

Ten men reported vasospastic symptoms in their hands during metoprolol treatment. They had no signs of occlusive arterial disease. The temperature reaction to local cooling was measured and no improvement was found after changing to pindolol. Vasospastic symptoms during beta-receptor blockade may arise in predisposed individuals irrespective of the type of beta-receptor antagonist used.

Influence of time and physical activity on blood pressure and heart rate during treatment with beta-blocking agents once daily

In a cross-over study of 52 middle-aged patients with mild to moderate essential hypertension, we have compared the effect and tolerability of 100 mg atenolol and 100 mg metoprolol given once daily. After 1 1/2 and 3 months of treatment, both systolic and diastolic blood pressure 24 hours after drug intake were significantly lower on atenolol. There were no significant differences after 3 months when blood pressure was read 3-4 hours after dose intake. During exercise, systolic blood pressure and heart rate were--at all work-loads--significantly lower on atenolol. Four patients on metoprolol and one patient on atenolol discontinued treatment owing to side-effects. The results support the need for thorough analysis of the duration of action and influence of physical activity and sympathetic tone in comparisons between presumedly equivalent antihypertensive drugs.

Metoprolol succinate therapy associated with erythema multiforme

Metoprolol succinate is a widely used medication for the management of hypertension, heart failure, and angina. We report the case of a 36-year-old woman who developed erythema multiforme after administration of a low dose of this drug. She also presented with pruritic burning pain throughout her body accompanied by chills. While erythema multiforme has been reported with carvedilol, this is the first observation of metoprolol succinate causing this and physicians should be aware of this potential, yet rare, side-effect.

[Perioperative beta-blockade for reduction of cardiovascular complications in non-cardiac surgery: advantages and disadvantages]

The results of the recently published PeriOperative ISchemic Evaluation (POISE) trial show that perioperative use of metoprolol in patients with atherosclerosis undergoing major non-cardiac surgery reduces the risk of cardiovascular complications. This effect was primarily produced by a 1.5% reduction in non-fatal myocardial infarction (MI), but this advantage was outweighed by a 0.8% increase in total mortality and a 0.5% increase in nonfatal stroke. These results, combined with previous meta-analyses, confirm that non-fatal MI is reduced at the cost of a statistically significant increase in stroke rate and a near significant increase in mortality. It is likely that the increase in complications is due to a high dose of metoprolol being given too shortly before the operation. These findings call for judicious perioperative use of adrenergic beta-antagonists in cardiac-high-risk patients undergoing high risk non-cardiac surgery. Dosage should be lower and administration should be implemented longer before the operation.

Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial

BACKGROUND

Trials of beta blockers in patients undergoing non-cardiac surgery have reported conflicting results. This randomised controlled trial, done in 190 hospitals in 23 countries, was designed to investigate the effects of perioperative beta blockers.

METHODS

We randomly assigned 8351 patients with, or at risk of, atherosclerotic disease who were undergoing non-cardiac surgery to receive extended-release metoprolol succinate (n=4174) or placebo (n=4177), by a computerised randomisation phone service. Study treatment was started 2-4 h before surgery and continued for 30 days. Patients, health-care providers, data collectors, and outcome adjudicators were masked to treatment allocation. The primary endpoint was a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal cardiac arrest. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00182039.

FINDINGS

All 8351 patients were included in analyses; 8331 (99.8%) patients completed the 30-day follow-up. Fewer patients in the metoprolol group than in the placebo group reached the primary endpoint (244 [5.8%] patients in the metoprolol group vs 290 [6.9%] in the placebo group; hazard ratio 0.84, 95% CI 0.70-0.99; p=0.0399). Fewer patients in the metoprolol group than in the placebo group had a myocardial infarction (176 [4.2%] vs 239 [5.7%] patients; 0.73, 0.60-0.89; p=0.0017). However, there were more deaths in the metoprolol group than in the placebo group (129 [3.1%] vs 97 [2.3%] patients; 1.33, 1.03-1.74; p=0.0317). More patients in the metoprolol group than in the placebo group had a stroke (41 [1.0%] vs 19 [0.5%] patients; 2.17, 1.26-3.74; p=0.0053).

INTERPRETATION

Our results highlight the risk in assuming a perioperative beta-blocker regimen has benefit without substantial harm, and the importance and need for large randomised trials in the perioperative setting. Patients are unlikely to accept the risks associated with perioperative extended-release metoprolol.