Key result
Phenylpropanolamine induced ventricular fibrillation in 50% of isolated rat hearts after nitric oxide synthesis inhibition with L-NAME, compared to 0% in normal hearts.
Why the study?
Does nitric oxide synthase inhibition enhance the myocardial toxicity of phenylpropanolamine in isolated rat hearts?
Population
Isolated hearts (n=8) from male Sprague-Dawley rats weighing 300-400 g
Comparison
Phenylpropanolamine infused at 0.05, 0.125… vs Phenylpropanolamine infused at the same doses…
Design
Preclinical
Authors
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Phenylpropanolamine may provoke ventricular fibrillation under nitric oxide deficiency; hypothesis-generating for human relevance and should not yet change practice.
Does nitric oxide synthase inhibition enhance the myocardial toxicity of phenylpropanolamine in isolated rat hearts?
Absolute Event Rate: 50% vs 0%
Inhibition of nitric oxide synthesis sensitizes the heart to the myocardial depressant effects of phenylpropanolamine and increases the risk for ventricular fibrillation.
Zaloga et al. (2000) studied Myocardial toxicity (n=8). Phenylpropanolamine (PPA) with N-nitro-L-arginine methyl ester (L-NAME) vs. Phenylpropanolamine (PPA) alone was evaluated on Ventricular fibrillation. Phenylpropanolamine induced ventricular fibrillation in 50% of isolated rat hearts after nitric oxide synthesis inhibition with L-NAME, compared to 0% in normal hearts.
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