Indomethacin blunts ethchlorvynol-induced pulmonary hypertension but not pulmonary edema.

Ethchlorvynol (10 mg/kg) causes transient pulmonary hypertension and an increased permeability pulmonary edema in sheep. To determine the role of cyclooxygenase and its metabolites, histamine, and catecholamines in both phenomena, we studied five groups of sheep: group I, placebo; group II, ethchlorvynol; group III, indomethacin with ethchlorvynol; group IV, diphenhydramine with ethchlorvynol; group V, phentolamine with ethchlorvynol. Indomethacin, but not diphenhydramine or phentolamine, blunted the pulmonary hypertensive response seen immediately following the ethchlorvynol injection. However, none of the drugs had any effect on the increased permeability pulmonary edema. We conclude that cyclooxygenase or its metabolites partially mediates the hypertensive response but not the increased permeability pulmonary edema seen in sheep following ethchlorvynol injection.