Aerosolized clenbuterol (NAB 365) and salbutamol in exercise-induced asthma.

The effect of clenbuterol (NAB 365) in inhibiting exercise-induced asthma was compared with that of salbutamol in a single-blind, placebo-controlled, crossover study. Single doses of 20 microgram clenbuterol and 200 microgram salbutamol were given by inhalation 180 minutes before exercise to 9 patients. The exercise used was treadmill running. Clenbuterol offered complete protection to 7 patients, partial protection to 1 and no protection to 1 patient. Salbutamol offered complete protection to 5 patients, partial protection to 1 and no protection to 3 patients. One patient was not protected by any treatment. The protective effects of the two beta-adrenergic bronchodilator drugs were similar (p = 0.42 for FEV1 and p = 0.10 for FEF25-75%). Placebo failed to prevent exercised-induced asthma in any patient. No adverse reactions were manifested or reported by the patients.

Comments on acute studies.

Sixteen papers which have examined the effects of Duovent (a combination of fenoterol 200 micrograms and ipratropium bromide 80 micrograms) in the treatment and prevention of bronchospasm by acute studies are reviewed. The studies suggest that the use of a combination of anticholinergic and beta 2-adrenergic drugs is justified, because the dominant mechanism in bronchospasm is the effect of acetylcholine on muscarinic receptors and because ipratropium bromide increases the action of fenoterol, so as to obtain prolonged bronchospasmolytic and antibronchoconstrictive effects with halved doses of beta 2-agonist.

Intravenous NAB 365 (clenbuterol) and terbutaline in exercise-induced bronchospasm (EIB).

In a single-blind, placebo-controlled, cross-over study, the effects of intravenous 20 micrograms NAB 365 (clenbuterol) and intravenous 250 microgram terbutaline were compared in nine asthmatic patients with bronchospasm induced by exercise. The exercise consisted of treadmill running. The two beta-adrenergic bronchodilator drugs effectively prevented post-exercise bronchospasm in eight of the nine patients. The effects were superior to those in the untreated group and in the placebo-treated group. Six of the patients treated with terbutaline complained of adverse reactions (tremor, palpitation, tachycardia). No adverse reactions were observed after clenbuterol.

Cold-air isocapnic hyperventilation test in the study of the effects and duration of action of Duovent. Comparison with fenoterol, salbutamol, disodium cromoglycate and placebo.

The cold-air isocapnic hyperventilation (CAIH) test is a challenge test for non-specific bronchitis which was recently incorporated into the study of bronchial hyperreactivity. As it is easy to perform and to reproduce, the CAIH test is regarded as a valuable examination in clinical pharmacology. We carried out a study using this test in 12 atopic asthmatics in intercritical phase. The patients were treated for a few days before, under double-blind conditions and random order, with Duovent (80 micrograms ipratropium bromide + 200 micrograms fenoterol), fenoterol (400 micrograms), salbutamol (200 micrograms), disodium cromoglycate (DSCG) (10 mg) and placebo. All the drugs were administered by aerosol 30 min before the test which was repeated at intervals of 120, 240 and 360 min after intake of the drug. Certain parameters of respiratory function were measured by dry spirometry (Vicatest 2 C) before administration of the drug as well as before and 0, 3, 5, 15, 30 and 60 min after each test. For the sake of brevity only the FEV1 values are shown in the figures since the other parameters all revealed a similar pattern. After placebo, all the patients reacted to the CAIH test with significant falls after each of the 4 tests, but there was no statistically significant difference between the 4 tests; there were no statistically significant differences between the pretreatment values in FEV1 recorded before each treatment (verum or placebo).(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchodilator effect of tiaramide hydrochloride.

A bioassay with tiaramide hydrochloride (THC) and placebo was performed in 32 non-asthmatic patients suffering from chronic obstructive lung disease. Each patient received one administration of THC (200 mg) and one of placebo according to a double-blind cross-over design. FVC, FEV1, FM25-75, PEF and FEF200-1,200 were measured before and at several intervals until 360 min after treatment. Significant differences were found between drug and placebo which gave no significant variations. It is concluded that THC is an effective and safe bronchodilator. The substained bronchodilator effect shown by THC appears to be a clinical advantage.

Effectiveness of nedocromil sodium versus placebo as additions to routine asthma maintenance therapy: a multicentre, double-blind, group comparative trial.

A total of 117 subjects took part in a double-blind, placebo-controlled trial of nedocromil sodium (4 x 4 mg daily by inhalation) in the management of patients with moderately severe bronchial asthma. Treatment was randomly allocated and was continued for 12 weeks following a 2-week baseline period on routine asthma therapy. Statistically significant differences for nedocromil sodium versus placebo were found for diary card asthma severity scores, morning and evening peak flow measurements and daily bronchodilator usage. The clinicians' assessments of asthma severity and global opinions of treatment efficacy were also significantly in favour of nedocromil sodium. Overall, the clinical status of these asthmatic patients was improved by adding nedocromil sodium onto their existing therapy.