Controlled Comparison of the Bronchodilator Effects of Three  -Adrenergic Stimulant Drugs Administered by Inhalation to Patients with Asthma

In studies on human isolated peripheral airway smooth muscle; 1 A concentration dependent f,-adrenoceptor tachyphylaxis was observed to isoprenaline. 2 Cross desensitization to other fl-adrenoceptor agonists was demonstrated.3 The desensitizatio1i was reversible with time. Hydrocortisone appeared to accelerate the recovery from the desensitized state. Low concentration isoprenaline (10-9 mol 1-') prevented recovery whereas cycloheximide 1.8 x 10-4 mol 1-1 had no noticeable effect on recovery. Continued occupancy of the receptor appears to prevent recovery. The recovery from the desensitized state does not apparently require synthesis of new proteins. 4 Bronchial wall cyclic AMP response to isoprenaline was attenuated after isoprenaline induced desensitization whereas total phosphodiesterase activity of bronchial wall was not altered by desensitization. Thus by exclusion the adenylate cyclase receptor complex may be altered in human peripheral airway smooth muscle fl-adrenoceptor tachyphylaxis.

Section: Introductionmentioning

confidence: 99%

Tachyphylaxis to beta‐adrenoceptor agonists in human bronchial smooth muscle: studies in vitro.

Davis¹,

Conolly²

1980

“…Data on pulse rates were thus calculated in terms of peak effect. (Choo-Kang et al, 1969) or by mouth (Cochrane, Clark & Hanan, 1973) in the management of asthma is well established. Ingram, Gaddie, Skinner & Palmer (1975) studied the response to intramuscular salbutamol in asthmatic patients.…”

Section: Resultsmentioning

confidence: 99%

“…The drug used most frequently by the subcutaneous route is adrenaline which should be administered with extreme caution to asthmatic patients with low arterial oxygen 'tensions and chronic asthmatic patients with a significant degree of emphysema and related heart disease (Goodman & Gilman, 1970). Choo-Kang, Simpson & Grant (1969) have shown that salbutamol is a selective 12 -adrenergic receptor agonist when administered by pressurized aerosol and is free from serious side effects after oral administration (Parker, Choo-Kang, Cooper, Cameron & Grant, 1971). A formulation suitable for subcutaneous administration is now available and it was decided to determine the optimum dose of salbutamol administered by this route.…”

Section: Introductionmentioning

confidence: 99%

Determination of the optimum dose of subcutaneous salbutamol in asthmatic patients.

Coady¹,

Stewart²,

Davis³

1976

Saline and salbutamol (250 mug, 500 mug, 750 mug, and 1000 mug) injections were administered under double‐blind conditions to seven chronic stable asthmatic patients. The response on the respiratory system (FEV1, FVC) and cardiovascular system (pulse rate, blood pressure and ECG) was monitored for 3 hours. Increasing the dose of salbutamol increased the peak and weighted average effects of FEV1 and pulse rate. The optimum dose, a titration of desired increases in FEV1 and undesirable increases in pulse rate, is 500 mug but doses up to 1000 mug may be administered if necessary.

“…During the last few years salbutamol has become widely used for the relief of bronchospasm (Choo-Kang, Simpson & Grant, 1969). In a double blind cross-over study in patients with chronic asthma treated for four weeks with either placebo or salbutamol, (2 or 4 mg) by mouth, Parker, Choo-Kang, Cooper, Cameron & Grant (1971) found that the larger dose produced significant improvement in the peak flow rate.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Salbutamol Tolerance

Sims

1974

I A double blind cross-over study was carried out on patients with reversible airways disease attending an out-patient clinic. 2 Twenty patients were given either salbutamol (200,g) or propellant by aerosol for two week periods and in another study twelve patients were given identical tablets containing either salbutamol (4 mg) or placebo for four week periods. Both forms of therapy were taken four times per day but stopped the evening before attending the clinic.3 The improvement in FEV, 10 min following salbutamol (200 Mg) by aerosol was measured after previous treatment with either salbutamol or placebo administered by aerosol and orally and the results were compared statistically. This failed to show a significant difference and suggests that regular treatment with salbutamol does not lead to a decreased response.