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The cardio‐toxicity of isoprenaline during hypoxia
Author(s) -
COLLINS J. M.,
McDEVITT D. G.,
SHANKS R. G.,
SWANTON J. G.
Publication year - 1969
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1969.tb08301.x
Subject(s) - isoprenaline , heart rate , blood pressure , anesthesia , medicine , ventricular fibrillation , cardiology , stimulation
1 The effects of the intravenous injection of isoprenaline on heart rate and arterial pressure has been studied in dogs artificially respired with room air or with 12% oxygen—88% nitrogen. 2 In dogs breathing room air, isoprenaline in doses from 0.02 to 500 μg/kg increased heart rate and reduced arterial pressure. Ventricular fibrillation was produced in one out of three dogs given 250 μg/kg. This was the only dog breathing room air which was killed by isoprenaline. 3 In dogs breathing room air the repeated intravenous injection at 5‐min intervals of 2.5 μg/kg increased heart rate and reduced arterial pressure. No ill effects were produced by six doses. 4 In dogs respired with 12% oxygen—88% nitrogen the Pa o 2 was reduced from 84 to 38 mm Hg with no changes in Pa co 2 . In these dogs death was produced by doses of isoprenaline which in dogs breathing room air produced normal responses. 5 The fatal dose of isoprenaline (10–50 μg/kg) reduced heart rate and arterial and pulse pressures; sinus rhythm persisted until arterial pressure was less than 50 mm Hg. Ventricular fibrillation did not occur; death occurred from cardiac asystole. 6 Death was produced in a similar way in dogs with hypoxaemia by giving four or five doses of isoprenaline (2.5 μg/kg) at 5‐min intervals or by two doses of 25 μg/kg. 7 The final reduction in arterial pressure during a fatal response resulted from a reduction in cardiac contractility. 8 These lethal effects of isoprenaline could be prevented by pretreatment with propranolol.