| Combination bronchodilators: antagonism of airway smooth muscle contractions in vitro. | |
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MedLine Citation:
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PMID: 463689 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The component drugs of fixed-dose combination bronchodilators may interact in a synergistic manner to antagonize airway contractions. To examine this hypothesis, combinations of ephedrine (E) and theophylline (Th) or salbutamol (S) and theophylline were tested for their ability to relax contracted guinea-pig airway smooth muscle in vitro. The combination bronchodilator effect was compared to the summed effects of the component drugs given individually (i.e. a theoretical additive response, Ta). Relaxation responses to combination bronchodilators were considered less-than-additive if significantly less than Ta, additive if non-significant and greater-than-additive or synergistic if the values were significantly greater than Ta. It was found that the E-Th combinations interacted primarily in an additive fashion to relax contractions induced by histamine, acetylcholine and 5-hydroxytryptamine at concentrations that produced one-half maximal contractile response (ED50). Similarly S-Th combinations interacted in an additive manner to reverse histamine and acetylcholine contractions. In the case of both E-Th and S-Th combinations, the drugs were more effective in reducing the smooth muscle contractions when given during rather than prior to the response. It may be concluded that beta-sympathomimetics and methylxanthines when combined do not interact in a synergistic fashion to produce relaxation of contracted airway smooth muscle. |
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Authors:
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C J Hanna; S H Roth |
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Publication Detail:
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Type: In Vitro; Journal Article |
Journal Detail:
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Title: Agents and actions Volume: 9 ISSN: 0065-4299 ISO Abbreviation: Agents Actions Publication Date: 1979 Apr |
Date Detail:
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Created Date: 1979-09-17 Completed Date: 1979-09-17 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0213341 Medline TA: Agents Actions Country: SWITZERLAND |
Other Details:
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Languages: eng Pagination: 18-23 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acetylcholine
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antagonists & inhibitors Airway Resistance / drug effects* Albuterol / pharmacology Animals Bronchodilator Agents / pharmacology* Drug Combinations Drug Interactions Ephedrine / pharmacology Guinea Pigs Histamine Antagonists Muscle Contraction / drug effects Muscle, Smooth / drug effects Serotonin Antagonists Theophylline / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Bronchodilator Agents; 0/Drug Combinations; 0/Histamine Antagonists; 0/Serotonin Antagonists; 18559-94-9/Albuterol; 299-42-3/Ephedrine; 51-84-3/Acetylcholine; 58-55-9/Theophylline |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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