Comparative effects of ephedrine on adrenergic responsiveness in normal and asthmatic subjects

Morris, Helen; Rusnak, Stuart A.; Selner, John C.; Barzens, Kathy; Barnes, John S.

doi:10.1016/0091-6749(78)90050-7

Cited by 17 publications

(3 citation statements)

References 33 publications

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“…A question that has been raised in regard to studies of asthmatic patients is the possibility that prior treatment of these patients with adrenergic bronchodilators rather than asthma itself has produced the observed fl-adrenergic desensitization (23,24). Since the dogs in our study have received no prior treatment with bronchodilators, such an effect cannot explain the impaired relaxation in response to isoproterenol seen in our asthmatic dogs.…”

Section: Discussioncontrasting

confidence: 43%

Depressed cyclic AMP levels in airway smooth muscle from asthmatic dogs

Rinard¹,

Rubinfeld²,

Brunton³

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

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Section: Discussioncontrasting

confidence: 43%

Depressed cyclic AMP levels in airway smooth muscle from asthmatic dogs

Rinard¹,

Rubinfeld²,

Brunton³

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

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“…The blunted subjective response seen in our patients could have resulted from ,B-adrenoceptor tolerance from long term therapy with 132-adrenoceptor agonists (Trautlein et al, 1976;Bengtsson et al, 1982). Similar changes also occur in leukocyte 13-adrenoceptors and cAMP responses (Conolly & Greenacre, 1976;Morris et al, 1978). In the present study no effect on heart rate or tremor was seen until 500 ,g and 1000 ,ug of salbutamol respectively.…”

Section: Discussionmentioning

confidence: 33%

Beta‐adrenoceptor responses to high doses of inhaled salbutamol in patients with bronchial asthma.

Lipworth

Clark

Dhillon

et al. 1988

Brit J Clinical Pharma

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1 Fourteen asthmatics (mean ± s.e. mean baseline FEV1 62 ± 6% of predicted) were given cumulative doubling doses of salbutamol by metered-dose inhaler as follows: 100 ,ug, 200 pg, 500 pg, 1000 pug, 2000 ,ug, 4000 ,ug. 2 Airways, tremor, haemodynamic and cyclic AMP responses were measured at each dose increment (made every 20 min). 3 There was a linear log dose-response relationship for each airways parameter (FEV1, VC, sGaw, FEF 50%). The plateau in the dose-response curve was not reached within our dose range. These changes were also mirrored in cyclic AMP responses. 4 There was a wide range in maximum airways response expressed in terms of absolute increase over baseline (95% confidence intervals: AFEV1 667-1483 ml; A VC 689-1695 ml; A sGaw 0.92-4.50 s-1 kPa-1; A FEF 50% 0.94-2.15 1 s-). Patients with a lower baseline showed a greater response in terms of percent increase in FEV1 (r = -0.83, P < 0.001). There was however, no correlation between baseline airway calibre and the dose required for maximum bronchodilatation.5 There were objective increases (mean ± s.e. mean) in both heart rate (maximum A HR of 14 ± 5 beats min-' at 4000 ,ug) and tremor power (maximum A Tr of 115 ± 44% at 2000 ,ug). These were not dose limiting side-effects as subjective symptoms were infrequent at higher doses. 6 Higher than conventional doses of salbutamol given by metered-dose inhaler may produce a distinct improvement in airways response without significant side-effects. There is a wide individual variation in airways response to inhaled salbutamol, although most patients required higher doses to achieve maximal bronchodilatation. The severity of asthma does not however predict the dose required for maximum airways response.

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“…In healthy volun teers a 4-week treatment course with inhaled salbutamol (S) brings about a reduction in airway response to the drug [2,3], In patients with bronchial asthma the results are contradictory: in some studies the airway response re mains constant, while in others it is reduced [4][5][6][7][8], Moreover, the effect of steroids on the (^-receptor is not entirely clear even if some studies appear to indicate that these drugs arc capable of restoring the receptor response to adrenergic stimuli, both in normal subjects desensitized by previous treatment [9] and in patients with bronchial asthma [2,10],…”

Section: Introductionmentioning

confidence: 99%

Effects of Therapeutic Doses of Salbutamol Alone and Combined with Beclomethasone Dipropionate on Airway Responsiveness and Cyclic AMP Plasma Levels in Asthmatic Patients

Ferrari¹,

Testi²,

Romito³

et al. 1993

Respiration

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Twelve asthmatic patients received by inhalation for 2 weeks, in a double-blind, cross-over design, beclomethasone dipropionate (BDP; 600 μg/day) plus salbutamol (S; 900 μg/day), or S (900 μg/day) alone. Before and after each treatment course the subjects received intravenous cumulative doses of S up to 200 μg. In basal conditions and immediately before the next dose forced expiratory volume in 1 s (FEV₁) and plasma cyclic AMP (cAMP) were measured. BDP + S treatment increased FEV₁ basal values (p < 0.05) whereas inhaled S resulted in unsignificant improvement of ventilatory parameters. The slopes of the dose-response curves of FΕV₁ and plasma cAMP to intravenous S were unaffected by the two treatment courses. Our results suggest that DBP + S, differently from S alone, improves ventilatory function in asthmatic patients and that neither S nor S + BDP seem to affect adrenergic function.

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Comparative effects of ephedrine on adrenergic responsiveness in normal and asthmatic subjects

Cited by 17 publications

References 33 publications

Depressed cyclic AMP levels in airway smooth muscle from asthmatic dogs

Depressed cyclic AMP levels in airway smooth muscle from asthmatic dogs

Beta‐adrenoceptor responses to high doses of inhaled salbutamol in patients with bronchial asthma.

Effects of Therapeutic Doses of Salbutamol Alone and Combined with Beclomethasone Dipropionate on Airway Responsiveness and Cyclic AMP Plasma Levels in Asthmatic Patients

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