Drugs
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Bivalirudin, a synthetic analogue of hirudin, is a specific and reversible inhibitor of thrombin which binds directly with both fluid-phase and clot-bound thrombin. In patients with unstable angina undergoing percutaneous transluminal coronary angioplasty (PTCA), results from a large well designed study and its reanalysis (n = 4312) indicate that bivalirudin is more effective than heparin in the prevention of ischaemic complications for up to 90 days after the start of treatment. In addition, among patients undergoing PTCA for post myocardial infarction (MI) bivalirudin may be more effective than heparin in preventing ischaemic complications for up to 180 days after treatment was started. Data from dose-finding studies indicate bivalirudin has potential in the treatment of patients with unstable angina not undergoing percutaneous coronary intervention (PCI); however, well designed comparative studies are needed before firm conclusions can be made. Among patients with acute ST elevation MI, randomised trials have demonstrated bivalirudin to be significantly more effective than heparin in improving early patency in patients receiving thrombolytic therapy with streptokinase. Data from the Hirulog and Early Reperfusion/Occlusion (HERO)-1 trial (n = 412) indicate that bivalirudin recipients were significantly more likely to have Thrombin Inhibition in Myocardial Ischaemia (TIMI) grade 3 flow at 90 to 120 minutes than heparin recipients. In addition, data from the HERO-2 trial (n = 17 073) show bivalirudin was significantly more effective than heparin in reducing adjudicated 96-hour reinfarction and 30-day investigator-reported death/reinfarction than heparin. Bivalirudin was as effective as heparin in reducing 30-day mortality. Data from a meta-analysis of four randomised trials among patients undergoing PTCA or treatment for acute coronary syndromes indicate that, at after 30 to 50 days of follow-up, bivalirudin was significantly more effective than heparin in reducing the incidence of nonfatal MI and the combined endpoint of death or nonfatal MI. The most significant adverse events associated with bivalirudin are bleeding complications. In individual trials, bivalirudin was as well tolerated as heparin with, in general, a reduced incidence of bleeding complications. Additionally, bivalirudin provides a more consistent, predictable anticoagulant response. In 4312 patients with unstable angina undergoing PTCA the incidence of retroperitoneal bleeding, blood transfusion and major haemorrhage was significantly lower in bivalirudin than heparin recipients. Data from the HERO-2 trial in patients with acute MI indicate that although bivalirudin recipients had a significantly higher incidence of mild or moderate bleeding than heparin recipients, there was no difference in intracranial haemorrhage, severe bleeding or transfusions. Data from a meta-analysis among 5674 patients with ischaemic heart disease show bivalirudin recipients were at a significantly lower risk of haemorrhagic events than heparin recipients. ⋯ Bivalirudin is an effective alternative to heparin in the prevention of ischaemic complications in patients with unstable angina undergoing PTCA. In addition, the drug has shown potential in the treatment of patients with unstable angina not undergoing PCI. For patients with MI, it is clear that bivalirudin can replace heparin in the management of MI where streptokinase is used as the thrombolytic agent. Further data are required on the efficacy of bivalirudin in patients undergoing thrombolysis with newer thrombolytics.
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Serious infection with vancomycin-resistant enterococci (VRE) usually occurs in patients with significantly compromised host defences and serious co-morbidities, and this magnifies the importance of effective antimicrobial treatment. Assessments of antibacterial efficacy against VRE have been hampered by the lack of a comparator treatment arm(s), complex treatment requirements including surgery, and advanced illness-severity associated with a high crude mortality. Treatment options include available agents which don't have a specific VRE approval (chloramphenicol, doxycycline, high-dose ampicillin or ampicillin/sulbactam), and nitrofurantoin (for lower urinary tract infection). ⋯ This category includes daptomycin (an acidic lipopeptide), oritavancin (LY-333328; a glycopeptide), and tigilcycline (GAR-936; a novel analogue of minocycline). Finally, strategies to suppress or eradicate the VRE intestinal reservoir have been reported for the combination of oral doxycyline plus bacitracin and oral ramoplanin (a novel glycolipodepsipeptide). If successful, a likely application of such an approach is the reduction of VRE infection during high risk periods in high risk patient groups such as the post-chemotherapy neutropenic nadir or early post-solid abdominal organ transplantation.
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Therapeutic drug monitoring (TDM) is a standard clinical technique used for many disease states, including many infectious diseases. As for these other conditions, the use of TDM in the setting of tuberculosis (TB) allows the clinician to make informed decisions regarding the timely adjustment of drug therapy. Such adjustments may not be required for otherwise healthy individuals who are responding to the standard, four-drug TB regimens. ⋯ TDM is only one part of the care of patients with TB. In isolation, it is of limited value. However, combined with clinical and bacteriological data, it can be a decisive tool, allowing the clinician to successfully treat even the most complicated TB patients.
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The coexistence of hypercholesterolaemia and diabetes dramatically and synergistically increases the risk of microvascular and macrovascular complications in patients. A single unifying mechanism of increased production of reactive oxygen species (ROS) by angiotensin II (Ang II) may serve as a causal link between hyperglycaemia and hypercholesterolaemia and many of the major pathways responsible for atherogenic and diabetic disorders. Several lines of evidence suggest a crucial role for Ang II-mediated oxidative stress in the pathogenesis of hyperglycaemia- and hypercholesterolemia-associated endothelial dysfunction. ⋯ Taken together, these data suggest that activation of the renin-angiotensin system is a mechanism for the initiation and progression of inflammatory cell infiltration found in early changes common to both hypercholesterolaemia and hyperglycaemia. While the base of information regarding ARBs in high-risk patients with diabetes and hypercholesterolemia is lacking, preclinical and pilot trial data suggest that the ARBs are reno- and vasculoprotective in these patients. Therapeutic blockade of Ang II AT(1) receptors in diabetic and hypercholesterolaemic humans by ARBs, with concomitant elevation in plasma and tissue Ang II levels, may provide vascular and renal protection not only by reducing AT(1) receptor-mediated pro-oxidative effects, but also by unopposed AT(2) receptor stimulation.
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This article reviews the use of low molecular weight heparin (LMWH) and antiplatelet agents in the treatment of unstable angina and non-ST segment elevation myocardial infarction (NSTEMI), which together account for 1 million hospitalisations annually in the US alone. Mortality and recurrent myocardial infarction (MI) in these conditions is currently approximately 8 to 16% at 1 month, and there is a need to optimise treatment further. Since their introduction, LMWHs have been shown to be successful and well tolerated in the treatment of unstable angina and NSTEMI, but differences have been seen in their efficacy compared with the parent compound, unfractionated heparin (UFH). ⋯ A further study (SYNERGY [Superior Yield of the New strategy of Enoxaparin, Revascularization and GlYcoprotein IIb/IIIa inhibitors]) will investigate the efficacy of the combination of enoxaparin with abciximab versus that of UFH and abciximab in a large cohort of 8000 patients. The use of GP IIb/IIIa agents and LMWH in patients with UA/STEMI has led to their use in those with ST-elevation MI, and studies indicate LMWH is efficacious and can be used safely as an adjunct to thrombolysis. New studies will investigate the use of these agents in patients with STEMI not undergoing thrombolysis and we await the results of these studies.