Effect of propranolol on respiratory function and exercise tolerance in patients with chronic obstructive lung disease

Cardioselective beta-blockers for chronic obstructive pulmonary disease

BACKGROUND

Beta-blocker therapy has a proven mortality benefit in patients with hypertension, heart failure and coronary artery disease, as well as during the perioperative period. These drugs have traditionally been considered contraindicated in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To assess the effect of cardioselective beta-blockers on respiratory function of patients with COPD.

SEARCH STRATEGY

A comprehensive search of the Cochrane Airways Group Specialised Register (derived from systematic searches of CENTRAL, MEDLINE, EMBASE and CINAHL) was carried out to identify randomised blinded controlled trials from 1966 to May 2005. We did not exclude trials on the basis of language.

SELECTION CRITERIA

Randomised, blinded, controlled trials of single dose or longer duration that studied the effects of cardioselective beta-blockers on the forced expiratory volume in 1 second (FEV1) or symptoms in patients with COPD.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted data from the selected articles, reconciling differences by consensus. Two interventions studied were the administration of beta-blocker, given either as a single dose or for longer duration, and the use of beta2-agonist given after the study drug.

MAIN RESULTS

Eleven studies of single-dose treatment and 9 of treatment for longer durations, ranging from 2 days to 12 weeks, met selection criteria. Cardioselective beta-blockers, given as a single dose or for longer duration, produced no change in FEV1 or respiratory symptoms compared to placebo, and did not affect the FEV1 treatment response to beta2-agonists. A subgroup analysis revealed no change in results for those participants with severe chronic airways obstruction or for those with a reversible obstructive component.

AUTHORS' CONCLUSIONS

Cardioselective beta-blockers, given to patients with COPD in the identified studies did not produce adverse respiratory effects. Given their demonstrated benefit in conditions such as heart failure, coronary artery disease and hypertension, cardioselective beta-blockers should not be routinely withheld from patients with COPD.

Cardioselective beta-blockers for chronic obstructive pulmonary disease

BACKGROUND

Beta-blocker therapy has a proven mortality benefit in patients with hypertension, heart failure and coronary artery disease, as well as during the perioperative period. These drugs have traditionally been considered contraindicated in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To assess the effect of cardioselective beta-blockers on respiratory function of patients with COPD.

SEARCH STRATEGY

A comprehensive search of EMBASE, MEDLINE and CINAHL was performed using the Cochrane Airways Group registry to identify randomised blinded controlled trials from 1966 to May 2001. The search was completed using the terms: asthma*, bronchial hyperreactivity*, respiratory sounds*, wheez*, obstructive lung disease* or obstructive airway disease*, and adrenergic antagonist*, sympatholytic* or adrenergic receptor block*. We did not exclude trials on the basis of language.

SELECTION CRITERIA

Randomised, blinded, controlled trials of single dose or longer duration that studied the effects of cardioselective beta-blockers on the forced expiratory volume in 1 second (FEV1) or symptoms in patients with COPD.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted data from the selected articles, reconciling differences by consensus. Two interventions studied were the administration of beta-blocker, given either as a single dose or for longer duration, and the use of beta2-agonist given after the study drug.

MAIN RESULTS

Eleven studies of single-dose treatment and 8 of treatment for longer duration, ranging from 2 days to 12 weeks, met selection criteria. Cardioselective beta-blockers produced no statistically significant change in FEV1 or respiratory symptoms compared to placebo, given as a single dose (Weighted Mean Difference -2.05% [95% Confidence interval, -6.05 to 1.96%]) or for longer duration (WMD -2.55% [95% CI, -5.94 to 0.84]), and did not significantly affect the FEV1 treatment response to beta2-agonists. Exacerbations and hospitalizations were recorded in all trials, but none occurred during the periods of study, in either group. A subgroup analysis revealed no significant change in results for those participants with severe chronic airways obstruction or for those with a reversible obstructive component.

REVIEWER'S CONCLUSIONS

The available evidence suggests that cardioselective beta-blockers, given to patients with COPD do not produce a significant short-term reduction in airway function or in the incidence of COPD exacerbations. However, the trials were small and of short duration. Given their demonstrated benefit in conditions such as heart failure, coronary artery disease and hypertension, cardioselective beta-blockers should be considered for patients with COPD, but administered with careful monitoring since data concerning long term administration and their effects during exacerbations are not available.

Respiratory function in the elderly and the effects of beta blockade

Bronchoconstriction, the main respiratory side effect from beta-blocking drugs, can be severe and precipitous in patients with asthma, but at most is very minor in patients with chronic bronchitis. Elderly patients with asthma and chronic bronchitis appear to run a similar risk from beta-blocking drugs as younger patients with these conditions, though there are no direct comparisons. Several studies have looked at the response of elderly patients to beta-blocking drugs, and the profile and incidence of respiratory side effects has been similar to those seen in studies of younger subjects. There is a greater danger in the elderly that a past history of asthma may be overlooked or that bronchoconstriction from a beta-blocking drug is attributed to other causes.

Comparative effects of celiprolol, propranolol, oxprenolol, and atenolol on respiratory function in hypertensive patients with chronic obstructive lung disease

The aim of the study was to compare the pulmonary effects of four beta-blockers with different ancillary properties: propranolol (non-beta 1 selective without ISA), oxprenolol (non-beta 1 selective with ISA), atenolol (beta 1 selective), and celipropol (beta 1 selective with mild beta 2-agonist and alpha 2-antagonist activity) in hypertensive patients with chronic obstructive lung disease. Ten asthmatic patients, all males, aged 50-66 years were studied. Entry criteria were a) DBP greater than or equal to 95 mmHg and less than or equal to 115 mmHg; b) FEV1 less than 70% of the theoretical values; c) FEV1 increase of at least 20% after salbutamol inhalation (200 micrograms). After a 2-week washout period on placebo, each patient received propranolol (80 mg/day), oxprenolol (80 mg/day), atenolol (100 mg/day), and celiprolol (200 mg/day) for 1 week, according to a randomized, cross-over design. At the end of the washout and of each treatment period, airway function, assessed by FEV1, FVC, and FEV1%, was evaluated by spirometry both in the basal condition and after salbutamol inhalation. Unlike propranolol and oxprenolol, which significantly reduced FEV1 and inhibited the bronchodilator response to inhaled salbutamol, atenolol and celiprolol did not significantly affect respiratory function and did not antagonize salbutamol effects. Celiprolol more closely approached placebo in its respiratory effects than did atenolol, although the differences were not statistically significant.

Measurement and cardiovascular relevance of partial agonist activity (PAA) involving beta 1- and beta 2-adrenoceptors

In the normal heart the ratio of beta 1/beta 2-receptors in both atria and ventricles is about 75:25; in the failing heart the ratio is about 60:40. Stimulation of either beta 1- or beta 2-receptors results in a positive chronotropic and inotropic response. In the periphery, with the exception of lipolysis, renin release, control of intraocular pressure and intestinal relaxation, beta 2-related activity predominates. The nature of the beta 2-receptor is being unravelled and it has now been cloned. The beta-receptor antagonist is 'anchored' via disulfide bonding. Subsequent events involve the regulatory protein guanine nucleotide which couples the receptor to adenylate cyclase. beta-receptor density may by up- or down-regulated. beta-stimulation down-regulates (uncouples and internalizes or sequestrates) and beta-antagonism up-regulates beta-receptor numbers, but the functional implications of such changes are not always clear. A partial agonist occupies a receptor site and competitively inhibits the full agonist (e.g. noradrenaline). A partial agonist differs from a full agonist in that maximal response of a tissue is less. When background sympathetic activity is absent or very low a partial agonist will act as an agonist, e.g. increase heart rate, but when background tone is high the partial agonist will behave functionally as an antagonist, e.g. decrease heart rate. In animals partial agonist activity (PAA) can be assessed in many ways. In the catecholamine-depleted (reserpine or syrosingopine), vagotomized or pithed, intact animal beta-activity can be assessed via changes in heart rate, cardiac contractility and atrioventricular conduction. Isolated organs can also be used such as atria, papillary muscle, tracheal, mesenteric artery and uterine preparations. The choice of animal is important as marked species differences in response can occur. In man assessing PAA is difficult due to the presence of an intact sympathetic system: the problem can be overcome by autonomic blockade of constrictor and vagal reflexes with prazosin, clonidine and atropine but leaving the beta-receptor mediated responses unimpaired. beta 1- and beta 2-selective PAA can also be gauged via an increased sleeping heart rate (basal sympathetic tone) in the presence and absence of a beta 1- and beta 2-selective antagonist. beta 1-selective PAA can also cause an increase in resting systolic blood pressure, beta 2-selective PAA may be further assessed by a fall in DBP, increased blood flow, fall in peripheral resistance or increased finger tremor.(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of intrinsic sympathomimetic activity on respiratory function during chronic beta blockade: comparison of propranolol and pindolol

The long term effect of beta blockers and the influence of intrinsic sympathomimetic activity on respiratory function were assessed in patients with chronic stable angina pectoris randomised to receive treatment with propranolol (n = 21) or pindolol (n = 19) for one year. Forced expiratory volume in one second (FEV1) had fallen by a mean of 240 ml after one year (p less than 0.001) in those treated with propranolol compared with 120 ml in those treated with pindolol (p less than 0.05). The difference between the groups was significant (p less than 0.01). Vital capacity fell significantly only in those treated with propranolol (p less than 0.05 at one year). In those in whom the basal ratio of FEV1 to forced vital capacity was low (less than 70%) propranolol, but not pindolol, caused a significant (p less than 0.05) fall in FEV1 throughout treatment. Long term administration of pindolol has a less adverse effect on respiratory function than propranolol, which results in a progressive deterioration in respiratory function over one year.

Ventilatory effects of beta 1-receptor-selective blockade with bisoprolol and metoprolol in asthmatic patients

In a double blind, placebo-controlled study the ventilatory effects of the beta 1-selective receptor blockers bisoprolol (EMD 33512) and metoprolol and their interactions with the beta 2-adrenoceptor agonist terbutaline were investigated in 8 asthmatic patients. Both beta-blockers, in all the doses given, caused a significant decrease in peak expiratory flow rate (PEFR). Vital capacity (VC) and forced expiratory volume in one second (FEV1) were significantly decreased only after 10 mg bisoprolol. Terbutaline inhalation caused the same significant improvements in FEV1 and PEFR during placebo as during bisoprolol 10 mg, bisoprolol 20 mg and metoprolol 100 mg. Both beta-blockers caused equal changes in heart rate (HR) at rest. Systolic and diastolic blood pressure (BP) decreased significantly after bisoprolol 20 mg and metoprolol 100 mg, but not after bisoprolol 10 mg. Inhalation of terbutaline up to a dose of 3.5 mg had no influence on HR and BP. The results point to good beta 1-selectivity of bisoprolol 10 mg and 20 mg and metoprolol 100 mg in asthmatic patients. No correlation was found between the plasma levels of the beta-blockers and the changes in the ventilatory indices, HR or BP.

Inhalation challenge with carbachol and isoproterenol to predict bronchospastic response to propranolol in COPD

Disabling propranolol-induced bronchospasm occasionally prevents use of this drug in patients with chronic obstructive pulmonary disease (COPD). A means was developed to identify patients who have high risk for this adverse effect using bronchial challenge by inhaling the parasympathomimetic drug, carbachol, and isoproterenol. After baseline pulmonary function tests, 12 patients with varying degrees of COPD and 13 control patients underwent maximal beta-blockade using intravenously administered propranolol during cardiac catheterization followed by repeat pulmonary function testing. Seven of the patients with COPD and ten of the control subjects were restudied while taking propranolol orally for at least three weeks. The results indicated that the bronchodilator response to inhaled isoproterenol does not reliably identify patients who develop bronchoconstriction with propranolol, but bronchoconstriction after inhaling carbachol is indicative of the high risk of developing bronchoconstriction from propranolol.

Comparative study of the ventilatory effects of three beta 1-selective blocking agents in asthmatic patients

A double blind, placebo-controlled study of the ventilatory effects of three new beta 1-selective adrenoceptor blockers was carried out in eight asthmatic patients. Measurements were performed before and 2, 3 and 4 h after ingestion of a single oral dose of placebo, atenolol 100 mg, metoprolol 100 mg or acebutolol 400 mg. At each time ventilatory indices and heart rate were assessed before, during and 15 min after an exercise test. The ventilatory indices were re-assessed after challenge with terbutaline 1.5 mg by inhalation. The three beta-blocking agents caused equal falls in exercise heart rate two hours after ingestion, indicating the equipotency of the cardiac effects. The three agents reduced significantly and to the same extent FEV1 and PEFR both before and after exercise. The respiratory indices clearly improved after stimulation with terbutaline. The response to terbutaline was less marked after acebutolol, which may indicate that it has a lower degree of beta 1-selectivity. The beta-blockers did not show any influence on bronchodilatation during exercise, or on exercise-induced bronchospasm.

Adverse effect of propranolol on airway function in nonasthmatic chronic obstructive lung disease

Bronchomotor tone is, in part, under beta-adrenergic control, and beta-adrenergic agonists are commonly used in the therapy for chronic obstructive pulmonary disease (COPD). Beta-adrenergic blockade with propranolol is contraindicated in asthmatic patients, yet little is known of its effect in patients with COPD. We studied 13 patients with COPD in a random-entry, double-blind crossover comparison of oral propranolol, 40 mg, and oral placebo on separate day. Pulmonary function worsened after administration of propranolol. Significant differences were present between the drugs' effect on heart rate, airway resistance, specific resistance, and flow rates at one hour, and persisting through four hours (p less than 0.01). Propranolol may have a deleterious effect on pulmonary function in nonasthmatic COPD. We conclude that when propranolol is to be used in patients with COPD, the short- and long-term effects on airway should be measured sequentially.

Life-threatening cold and exercise-induced asthma potentiated by administration of propranolol

We present two patients with acute respiratory failure secondary to cold and exercise-induced asthma. Neither patient had a prior history of asthma, and both had recently been placed on therapy with propranolol for treatment of hypertension. We discuss the postulated mechanism of bronchospasm in these patients. In addition, we urge aggressive searching for any change in respiratory symptoms in patients receiving propranolol.

Comparative effect of nadolol and propranolol on exercise tolerance in patients with angina pectoris

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Comparison of atenolol and oxprenolol in patients with angina or hypertension and co-existent chronic airways obstruction

1 The effects of atenolol (50 mg and 100 mg) and oxprenolol (80 mg) on respiratory function were studied in ten patients with angina pectoris or hypertension complicated by chronic airways obstruction. 2 In patients with "fixed" airways obstruction, neither atenolol nor exprenolol significantly affected airways resistance. 3 In patients with "labile" airways obstruction, atenolol did not produce a significant increase in airways obstruction, whereas oxprenolol did. 4 Following isoprenaline challenge (1500 microgram by inhalation), atenolol permitted full bronchodilatation, whereas oxprenolol almost completely blocked the action of isoprenaline. 5 Partial agonist activity appears to be of less clinical importance than cardioselectivity.

Side effects and contraindications of beta-receptor blocking agents

Unwanted effects of beta-receptor blocking agents can be divided into three categories: 1. Those arising specifically from the pharmacologic, i.e., beta-blocking action. 2. Side effects not directly (or not with certainty) related to beta-blockade. 3. Adverse and potentially specific reactions to individual beta-blocking agents. Category 1 covers the majority of adverse effects (heart failure, severe bradycardia and hypotension, arterial insufficiency, increased airways resistance, gastrointestinal symptoms, hypoglycemia). These can largely be avoided by proper selection and preparation of patients. Category 2 covers cutaneous reactions (rashes, alopecia, pruritus), purpura (thrombocytopenic and nonthrombocytopenic) etc. as well as side effects attributable to the central nervous system (antianxiety effects, nightmares etc.). In the third category the "oculo-cutaneous syndrome" associated with practolol is discussed.

Reduced respiratory responses to carbon dioxide after propranolol: a central action

In a double-blind study in six subjects propranolol significantly reduced the respiratory sensitivity to carbon dioxide rebreathing. This effect seems to have been due to beta-adrenergic blockade, since it was not seen with D-propranolol. In two subjects increasing doses of propranolol caused progressive reductions in respiratory sensitivity to values below normal and similar to those of patients with ventilatory failure. These changes are probably due to a central action of propranolol.