Coxibs have both pro-thrombotic and impairment of wound healing effects. So why don’t these cancel each other out?

Thrombosis and impairment of wound healing are not contradictory. Instead, wound healing is a complex process that occurs over days to weeks, and even sometimes months or years, involving the recruitment of a cascade of many cell types.

Haemostasis, which is dependent on COX-1 and platelet aggregation, is only a small component of wound healing that occurs over seconds to minutes when there is bleeding. All the rest of the process over subsequent days and weeks depends on cascades initiated by COX-2-dependent mechanisms. When there is tissue damage without bleeding, all the rest of the COX-2-dependent processes still occur without the need for thrombosis. So even if there is enhanced thrombosis, there can still be impaired wound healing.