[Effects of KW-3635 on the diuretic action of furosemide in rats].

The effects of KW-3635 (sodium (E)-11-[2-(5,6-dimethyl-1-benzimidazolyl) ethylidene]-6,11-dihydrodibenz-[b,e]oxepine-2-carboxylate monohydrate, CAS 127166-41-0), a novel thromboxane A2 (TxA2) receptor antagonist, on furosemide diuresis were examined in rats. After an overnight fast, the rats received either saline or drugs, and 6-hr urine samples were collected. Urine volume, urinary excretion of electrolytes and urine TxB2 were measured. The administration of KW-3635 (10, 30 mg/kg, p.o.) or BM-13505 (10, 30 mg/kg) significantly increased the diuretic effect of furosemide (10 mg/kg, p.o.). Neither drug had any effect on urinary excretion of TxB2. These results demonstrated that the diuretic effect of furosemide was potentiated by TxA2 receptor blockade with KW-3635 or BM-13505. It is suggested that the diuretic effect of furosemide might be modulated by renal production of TxA2 elicited by this drug.