Comparative study of cardiovascular, neurological and metabolic side effects of 8 narcotics in dogs. Pethidine, piritramide, morphine, phenoperidine, fentanyl, R 39 209, sufentanil, R 34 995. III. Comparative study of the acute metabolic toxicity of the narcotics used in high and massive doses in curarised and mechanically ventilated dogs.

The I.V. administration in dogs of high and massive doses of narcotics produced an acute rise in CO2 consumption, a rise of plasma catecholamines and other slight biochemical and metabolic perturbances. A general trend towards metabolic acidosis and hypermetabolism was noticed but important differences appeared according the drugs and doses chosen. The safety margin for metabolic toxicity (ratio between IV doses producing severe metabolic side-effects and doses necessary for deep surgical analgesia) were calculated for each narcotic and found as follows: 1 for pethidine, 3.3 for piritramide, 13 for morphine and phenoperidine, 12.5 for R 39 209, 60 for fentanyl, 800 for sufentanil and 4 000 for R 34 995. Drug associations may decrease or increase the metabolic safety margin of the narcotics. Beneficial associations with morphinomimetics are found with droperidol, etomidate and flunitrazepam.