Prazosin, an alpha1-adrenoceptor antagonist, partially inhibits exercise-induced asthma

Barnes, Peter J.; Wilson, Nicola; Vickers, H

doi:10.1016/0091-6749(81)90193-7

Cited by 51 publications

(21 citation statements)

References 34 publications

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“…These effects probably account for the development of bronchial obstruction ascribed to stimulation of α 1 -adrenoceptors in some asthmatic subjects [7,[27][28][29]. They are also consistent with reported beneficial effects of various α 1 -adrenoceptor antagonists in asthma [30][31][32]. However, neither the consistency of α 1 -adrenoceptor agonists in causing bronchial obstruction nor the specificity of α 1 -adrenoceptor antagonists to prevent it are unanimously recognized [33,34], and there is debate as to the relevance of using α 1 -adrenoceptors blocking drugs in asthma [34].…”

Section: Discussionsupporting

confidence: 70%

Effects of pretreatment with inhaled methoxamine on bronchial responses to histamine in asthmatic subjects

Phan-Puibaraud¹,

Regnard²,

Monchi³

et al. 1995

Eur Respir J

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The underlying mechanisms of bronchial obstruction in asthma are complex. Both bronchospasm and bronchial oedema are thought to play pivotal roles in asthma, but their respective importance in a given asthmatic individual is unknown. To address this question, we assessed the effects of pretreatment with inhaled methoxamine, a potent alpha 1-adrenoceptor agonist, on bronchial response to inhaled histamine in 10 asthmatic subjects. The study was conducted according to a double-blind, cross-over, randomized and placebo-controlled design. In each subject, dose-response curves for the effects on forced expiratory volume in one second (FEV1) of serially doubling doses of inhaled histamine were obtained on three different days, 15 min after pretreatment with either methoxamine (10 mg) or duplicated placebo. Histamine, first dose 100 micrograms (543 nmol), was delivered by a breath-activated dosimeter every 5 min. FEV1 was measured in triplicate after each dose and the largest value was retained. There was no difference in baseline and prechallenge FEV1 after placebo and methoxamine. Mean coefficient of variation of decrease in FEV1 induced by histamine on the two placebo days was 6.7 +/- 2%. On average, the bronchial responses to histamine were not modified by pretreatment with methoxamine as compared to placebo (delta FEV1 = 0.83 +/- 0.14 l on methoxamine versus 0.85 +/- 0.11 l and 0.86 +/- 0.13 l on the two placebo days).(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionsupporting

confidence: 70%

Effects of pretreatment with inhaled methoxamine on bronchial responses to histamine in asthmatic subjects

Phan-Puibaraud¹,

Regnard²,

Monchi³

et al. 1995

Eur Respir J

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“…However, thymoxamine is non-specific for alpha-adrenoceptors and it was uncertain whether its efficacy could be attributed to its alpha-blocking properties alone. A recent study on the specific dpha-blocker prazosin demonstrated its efficacy as an aerosol in a dose of 2 mg in six of 10 patients with EIA (19). This observation supports the theory that alpha-receptor stimulation may occur as a result of the release of noradrenaline during exercise (see elsewhere in this review).…”

Section: Drugs Whzch Preuent Eiasupporting

confidence: 63%

Current Concepts of Exercise‐Induced Asthma

Anderson

1983

Allergy

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“…Prazosin is free of the pharmacological activity characteristic of other a-adrenoceptor antagonists such as histamine HI-receptor antagonism and inhibition of t2-adrenoceptors. In the present study we did not determine the effect of prazosin on histamineinduced bronchoconstriction, but others have investigated this using a higher dose of prazosin (Barnes et al, 1981b) and found no histamine Hl-receptor antagonism.…”

Section: Analysis Of Resultsmentioning

confidence: 89%

“…This allegedly inert vehicle caused shifts to the right of the dose response curves to both histamine and methoxamine. Barnes et al (1981b) used propylene glycol as the diluent for prazosin to investigate the role of a-adrenoceptors in exercise-induced bronchospasm. In determining whether prazosin affected histamine-induced bronchoconstriction, they reported no significant differences between propylene glycol and prazosin dissolved in propylene glycol.…”

Section: Analysis Of Resultsmentioning

confidence: 99%

“…This study reports the use of inhaled prazosin to antagonize bronchoconstrictor effects of methoxamine. Prazosin is not sufficiently soluble in water or saline and therefore we intended to use propylene glycol, a vehicle used by others for administration of prazosin (Barnes et al, 1981b). During the course of the study it became apparent that propylene glycol was unsuitable for this purpose.…”

Section: Introductionmentioning

confidence: 99%

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The action of prazosin and propylene glycol on methoxamine‐induced bronchoconstriction in asthmatic subjects.

Black¹,

Salome²,

Yan³

et al. 1984

Brit J Clinical Pharma

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The effect of 1 mg inhaled prazosin on bronchoconstriction induced by methoxamine was investigated in seven asthmatic subjects. Prazosin caused significant inhibition of the methoxamine‐induced bronchoconstriction in six of the seven patients. These findings suggest that methoxamine produces bronchoconstriction in asthmatic subjects via stimulation of alpha‐adrenoceptors. In previous studies propylene glycol has been used as a vehicle for delivery of prazosin. This substance was found to cause significant inhibition of methoxamine effects and to shift the dose response curve to histamine to the right in four of seven patients.

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Prazosin, an alpha1-adrenoceptor antagonist, partially inhibits exercise-induced asthma

Cited by 51 publications

References 34 publications

Effects of pretreatment with inhaled methoxamine on bronchial responses to histamine in asthmatic subjects

Effects of pretreatment with inhaled methoxamine on bronchial responses to histamine in asthmatic subjects

Current Concepts of Exercise‐Induced Asthma

The action of prazosin and propylene glycol on methoxamine‐induced bronchoconstriction in asthmatic subjects.

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