[Investigations in animal experiments into the influence of the beta-1-selective blocking agent metoprolol on the cardiovascular and metabolic side effects of the tocolytic fenoterol].

: The influence of the highly selective beta-1-adrenergic blocker Metoprolol on cardiovascular and metabolic side effects of the beta-mimetic Fenoterol, used for labour inhibition, was investigated in anesthetized mongrel dogs. In a dosage of 1.5 microgram/kg BW/min Metoprolol antagonized the positive inotropic and chronotropic cardiac effects of Fenoterol (0.06 microgram/kg BW/min) thus compensating the impaired energetic balance of the myocardium. As expected, there was no influence on the beta-mimetic mediated metabolic alterations. Taking into account its pharmacologic actions, the additional application of Metoprolol in labour inhibition with beta-mimetics seems to be advantageous. On account of the proven results a reduction of the more or less considerable missensations and a cardioprotective effect may be expected.