Thrombosis drugs affecting

Argatroban is a small molecule thrombin inhibitor that is FDA approved for use in patients with heparin-induced thrombocytopenia (HIT) with or without thrombosis and coronary angioplasty in patients with HIT. It, too, has a short half-life, is given by continuous intravenous infusion, and monitoring is done by aPTT. Its clearance is not affected by renal disease but is dependent on liver function. The drug requires dose reduction in patients with liver disease. Patients on argatroban will demonstrate elevated INRs because of test interference, rendering the transition to warfarin difficult. 

Based on the differences between hemostasis and thrombosis mechanisms, which, even though similar, are developing through different routes, the practical point related to antithrombotic therapies is that increased concentrations of antithrombotic drugs will affect thrombosis as well as hemostasis but, as the latter is a weaker process than the former, any important increase in anticoagulant potential will produce a bleeding tendency before stopping thrombosis (26). 

The droplet size distribution of the emulsions may change as a consequence of photochemical reactions in TPN formulations. Physical stability of the emulsion is an important issue for patient safety because coalescence of the disperse phase and a subsequent increase in globule size could result in thrombosis in vivo (Ford, 1988). Thus, stability testing of TPN emulsions should also include size distribution analyses after exposure to irradiation, as described by Williams et al. (1990). Ideally, the emulsion should be formulated so that the disperse droplets have a size distribution corresponding to the chylomicra (500 to 1000 nm), which are the natural transport systems for fat through the blood stream (Ford, 1988). The size of the disperse droplets should not be affected by the storage temperature or exposure to optical irradiation. However, it is important to note that addition of any substance (e.g., a drug) to a photochemically stable TPN preparation may alter the photoreactivity and thus the photochemical stability of the formulation. 

Vasculitis affecting the central nervous system (CNS) represents a heterogeneous group of inflammatory diseases that may be idiopathic or associated with autoimmune diseases, infections, drug exposure, radiation, or cancer. Inflammatory cells invade vessel walls, and neuropeptide release increases vasomotor reactivity. These properties lead to vessel narrowing. There is also loss of normal endothelial anticoagulant properties and vessels have increased susceptibility to thrombosis. Consequently, patients with vasculitis develop ischemic and thrombotic infarctions. There is also altered wall competence, which can result in dissection or vessel wall disruption with intracranial hemorrhage. MRA is clinically used to screen for vasculitis, but is less sensitive than DSA (Fig. 6.20). One study of 14 patients with suspected vasculitis reported that MRA can detect distal stenoses in vasculitis with a... 

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