Thromboxanes blockers

Drugs that target other sites of platelet action include thromboxane synthetase inhibitors, serotonin or 5-hydroxytryptamine (5-HT2) receptor blockers, and thromboxane A2 receptor blockers, in addition to cyclooxygenase inhibitors and prostaglandin analogues. 

Figure 12.11. StractuiES of two thromboxane A receptor blockers (a), and of BM 573, a combined antagonist of both TXA receptor and TXA synthase (b). BM 573 was derived from the diuretic torasemide.

Hoet B, Amout J, Van Geet C, Deckmyn H, Verha e R, Vermylen J. Ridogrd, a cnnbined thromboxane synthase inhibitor and receptor blocker, decreases elevated plasma p-thrombc>globulin levds in patients with documented peripheral arterial disease. Thromb Haemost 1990 64 87-90... 

A direct effect of AmB on cell function was suggested by in vitro experiments, which demonstrated a vasoconstrictor action of AmB in perfused afferent arterioles and isometrically contracting rings of rabbit aorta or renal artery, effects which were prevented in Ca -free medium and by Ca" " channel blockers or theophylline [103]. Thus, AmB-induced reductions in RBF or GFR are not secondary to activation of TGF, but due to its direct vasoconstrictor effect. A role for thromboxane A2 has also been suggested based upon partial inhibition of the AmB-induced vasoconstriction and reduction in GFR by pretreatment with ibuprofen or a thromboxane receptor antagonist [104]. 

Gresek. P. era/. (1991) Thromboxane synthase inhibitors, thromboxane receptor antagonists and dual blockers in thrombotic disorders. Trends Pharmacol Sci., 12.158-163. 

Guo et al. (1990) working with an in vivo rabbit model showed that pre- or posttreatment with indomethacin, an inhibitor of thromboxane and prostacyclin production but not of leukotriene production, partially blocked phosgene-induced pulmonary oedema. The leukotriene receptor blockers FPL 55712 and LY 171883 dramatically reduced the oedema when given post-exposure to phosgene. 

Thromboxane receptor blockers Platelet-Promoting Agents... 

Urbaschek, R., Patscheke, H., Stegmeier, K. and Urbaschek, B. (1985). The effect of a thromboxane receptor blocker in endotoxin shock. Circ. Shock, 16, 71... 

Another study speculates on the attribution of diarrhoea induced by CPT-11 to effects on secretion. In this study, thromboxane synthase inhibitors such as indomethacin and a thromboxane A2 receptor blocker depressed the short-circuit current caused by CPT-11 [181]. This current depends on the presence of Cf ions and is considered to reflect the amount of secretion of these ions. Therefore, it was postulated that CPT-11 induces secretion of Cr ions mediated by eicosanoid and this secretion may be related to the occurrence of diarrhoea. 

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