title: The effect of antihistamine, endothelin antagonist and corticosteroid prophylaxis on contrast media induced bronchospasm.
abstract: Bronchospasm is a well recognized adverse reaction to radiographic contrast media (RCM) and may occur more frequently in asthmatics and atopics. This study was designed to identify RCM which are most likely to cause bronchospasm and to investigate underlying mechanisms mediating this response. Guinea pigs (mean body weight 550 g, n = 46) were anaesthetized with Hypnorm (5 ml kg-1) and Hypnovel (2 ml kg-1) and tracheal, jugular and pleural cannulae introduced. Total airways resistance (Raw) was calculated from the slope of the pressure/flow relationship. The effects of RCM (diatrizoate 370 mgI ml-1, ioxaglate 320 mgI ml-1, iotrolan 300 mgI ml-1 and iopromide 300 mgI ml-1) at a dose of 4 ml kg-1 body weight or control solutions matched for volume, pH and osmolarity administered via the jugular vein on Raw were studied. The effects of pre-treatment (30 min before the administration of RCM) with antihistamine (Mepyramine (30 mg kg-1 i.p.)) or non-selective endothelin receptor antagonist (SB209670 (1 mg kg-1 i.v.)) were investigated. The effectiveness of corticosteroids prophylaxis (prednisolone (20 mg kg-1 i.p.)) administered 18-24 h and 1 h pre-RCM was also assessed. Control animals received normal saline pre-treatment before RCM administration. Lungs were taken for histological examination 30-40 min post-administration of RCM. Only ioxaglate caused a significant (p < 0.05) increase in Raw (5.19 +/- 0.58 to 13.95 +/- 3.53 mmHg ml-1 min-1). Neither mannitol nor saline control solutions had any effect on Raw. Pre-treatment with Mepyramine, SB209670 or prednisolone caused no significant change in the ioxaglate induced increase in Raw. Histological examination of lung tissue from ioxaglate treated animals showed no important abnormalities. In summary, only the ionic dimer ioxaglate caused an increase in Raw. This effect was independent of osmolarity and could be the result of the chemical composition of the contrast agent. It was not an inflammatory response and could not be prevented by prophylactic treatment with antihistamine, endothelin antagonist or corticosteroids. The mechanisms responsible for the increase in Raw remain uncertain.
authors.affiliation: Department of Respiratory Medicine, Sheffield University Medical School, UK.
authors.forename: E A
authors.initials: EA
authors.lastname: Laude
authors.forename: C J
authors.initials: CJ
authors.lastname: Emery
authors.forename: S K
authors.initials: SK
authors.lastname: Suvarna
authors.forename: S K
authors.initials: SK
authors.lastname: Morcos
mesh_terms: D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D001986:Bronchial Spasm / Q000139:chemically induced / Q000517:prevention & control*; D003287:Contrast Media / Q000009:adverse effects*; D004353:Drug Evaluation, Preclinical; D065128:Endothelin Receptor Antagonists; D006168:Guinea Pigs; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D007485:Ioxaglic Acid / Q000009:adverse effects*; D008297:Male; D011239:Prednisolone / Q000627:therapeutic use; D011738:Pyrilamine / Q000627:therapeutic use
chemical_list: D000893:Anti-Inflammatory Agents; D003287:Contrast Media; D065128:Endothelin Receptor Antagonists; D006634:Histamine H1 Antagonists; D011239:Prednisolone; D011738:Pyrilamine; D007485:Ioxaglic Acid