Combination Of Salbutamol Research Articles

Effects of BRL38227, salbutamol, and aminophylline, alone and in combination, on plasma potassium and on the heart

AbstractThe present study was undertaken in order to examine the effects of the potassium channel activator BRL38227 and of aminophylline on hypokalaemia, cardiac stimulation (increased heart rate and contractility, dQ/dt), and electrocardiogram (ECG) changes induced by the β2‐adrenoceptor agonist, salbutamol in the anaesthetised cat. Salbutamol (1.25 μg.kg−1min−1), but not BRL38227 (0.1–1.0 μg.kg−1 min−1), infusion elicited a marked hypokalaemia (plasma K+ >2.5 mmolliter −1). This dose of salbutamol also elicited an immediate cardiac stimulation which appeared to be maximal and changes in ECG were evident as a reduction in QTc interval (20%) and T‐wave height (80%). Cardiac stimulation following either BRL38227 or aminophylline was more gradual in onset, the maximum response being about 50–80% of the salbutamol effect. No ECG changes were observed in cats receiving BRL38227 whilst T‐wave amplitude was reduced (50–60%) following aminophylline. Combination of salbutamol with aminophylline resulted in a greater degree of hypokalaemia, cardiac stimulation, and T‐wave depression. The salbutamol‐induced reduction in QTc was converted to a slight prolongation after infusion for 75 min. The ECG changes observed were not indicative of arrhythmia. Conversely, BRL38227 had no effect on salbutamol‐induced hypokalaemia, cardiac stimulation, or T‐wave depression, though the degree of QTc interval shortening was reduced. When BRL38227 was administered in conjunction with aminophylline, plasma potassium and QTc were unchanged. Depression of T‐wave amplitude by aminophylline was slightly reduced in the combination group. Effects on heart rate and dQ/dt were similar to those seen for BRL38227 alone. Salbutamol‐induced hypokalaemia was reversed by the nonselective β‐adrenoceptor antagonist, propranolol, but not by the β1‐adrenoceptor selective antagonist, atenolol, confirming a β2‐adrenoceptor selective effect. Cardiac stimulation was reversed by both propranolol and atenolol. In conclusion, salbutamol‐induced hypokalaemia, cardiac stimulation, and ECG changes, as well as the additive effect of aminophylline, were demonstrated in the anaesthetised cat, but were unchanged by BRL38227. Furthermore, combination of BRL38227 with aminophylline did not result in any adverse effects on the parameters measured. Thus, on the basis of these results in the cat, combination of BRL38227 with the bronchodilator drugs, salbutamol or aminophylline, would not be expected to exacerbate the cardiovascular effects of these drugs. © 1992 Wiley‐Liss, Inc.

Childhood eosinophilic fasciitis presenting as inflammatory polyarthritis and associated with selective IgA deficiency.

A 13 year old school boy presented with seronegative inflammatory polyarthritis after a flu-like illness. Four months later clinical features of eosinophilic fasciitis became apparent. After histological diagnosis treatment was started with prednisone 40 mg daily, with a good response. Routine investigations showed persistent selective IgA deficiency.

Combination of Theophylline and Salbutamol for Arrhythmias in Severe COPD

We conducted a single-bind placebo controlled study using 24-hour continuous ambulatory electrocardiographic recordings. The arrhythmogenic potential of the combination of salbutamol and theophylline was investigated in 25 ambulatory subjects with severe chronic airflow obstruction (mean age 65 +/- 8 SD, mean FEV1 31 percent +/- 13 SD predicted). Asymptomatic arrhythmias were very prevalent in the study population: 76 percent of the patients had runs of supraventricular tachycardia while 24 percent had runs of ventricular tachycardia. Individual arrhythmia frequency showed greater between-test variability than previously described in non-COPD subjects. The mode of administration of salbutamol may have affected arrhythmia frequency in that subjects using aerosol nebulizers had more ventricular extrasystoles than those using metered dose inhalers. Although the addition of theophylline to salbutamol significantly increased heart rate and supraventricular extrasystoles, there was no statistically significant increase in ventricular arrhythmias.

Inhibition by drugs of passive cutaneous anaphylaxis-induced skin histamine decrease.

Passive cutaneous anaphylaxis (PCA) was produced in the rat with mouse IgE-rich antiserum. The effect of drugs on the PCA-induced skin histamine decrease and leakage of protein-bound dye was studied. Salbutamol (0.5 mg/kg i.v. or 1.0 mg/kg s.c.) and cromoglycate (10 mg/kg i.v.) significantly inhibited the skin histamine decrease. A combination of salbutamol (0.5 mg/kg i.v. or 1.0 mg/kg s.c.) and aminophylline (25 mg/kg i.v. or 75 mg/kg s.c.) had an additive or greater than additive effect on the histamine decrease. Salbutamol (1.0 mg/kg s.c.) inhibited the dye leakage markedly, and aminophylline (75 mg/kg s.c.) slightly. These results indicate that the decrease in the skin histamine content is useful as an index of the in vivo inhibitory effect of antiallergic drugs on the antigen-induced histamine release.

Inhibition of adjuvant arthritis by salbutamol and aminophylline

Salbutamol (3 mg/kg) and aminophylline (75 mg/kg) were administered s.c. to rats separately or in combination after intradermal injection of adjuvant into the left hind paw. The paw volume was measured plethysmographically; tissue cyclic AMP content was determined by a protein binding assay following whole body microwave irradiation. The combination of salbutamol and aminophylline given daily significantly inhibited the swelling response in both the adjuvant-injected and the non-injected paws. This drug combination significantly increased the cyclic AMP levels in inflamed tissue of the adjuvant-injected hind paw and in lymphoid tissue such as the spleen and thymus. The combined treatment seems to have immunosuppressive as well as anti-inflammatory effects on adjuvant-induced arthritis.

A comparative study of atropine methonitrate, salbutamol, and their combination in airways obstruction.

Dose-response relationships of the cholinergic antagonist, atropine methonitrate, and the beta-adrenergic agonist, salbutamol, were examined by cumulative dose techniques. A wet aerosol, 1.5 mg atropine methonitrate produced a maximum response. The response to 200 microgram of salbutamol from a pressurised aerosol was close to maximum. Secondly, the bronchodilator response of salbutamol microgram was compared with atropine methonitrate 2 mg and placebo in 18 asthmatic patients in a randomised crossover study. In 11 of them the bronchodilator response of the combination of salbutamol and atropine methonitrate was evaluated. Atropine methonitrate produced a similar peak bronchodilator effect to salbutamol, but its effect was more prolonged, the response being significantly greater at four and six hours than with salbutamol. The combination of drugs produced a significantly greater and more lasting bronchodilatation than either of the drugs alone. Despite mild side effects, atropine methonitrate, either alone or in combination with an adrenergic drug, appears to have a place in the treatment of sever reversible airway obstruction not adequately controlled by conventional treatment.

A comparison of the bronchodilator activity of Sch 1000 and salbutamol

The effects of the β 2-adrenergic agonist, salbutamol, 200 μg, and the cholinergic antagonist, Sch 1000, 40 μg, have been compared in 25 asthmatic patients using a single dose, double-blind, crossover trial design. Salbutamol aerosol produces a greater degree of bronchodilatation than Sch 1000 aerosol during the initial three hours following drug administration. There is no significant difference in the bronchodilator effects of the two drugs in the interval four to eight hours after drug administration. Nonatopic patients showed less difference in bronchodilator response to each of the two drugs than atopic patients. Neither drug showed any significant adverse effect on blood pressure, pulse rate, or electrocardiogram. In six asthmatic patients the effect of the combination of salbutamol, 200 μg, and Sch 1000, 40 μg, was evaluated. The combination produced a longer duration of bronchodilatation than either drug alone when compared to placebo.