Current medicinal chemistry
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Review Comparative Study
New antipsychotics and schizophrenia: a review on efficacy and side effects.
The first compounds showing efficacy in the treatment of schizophrenia and other psychotic disorders was chlorpromazine, an anti-histaminic compound casually observed to possess antipsychotic effects. The discovery of the real mechanism of action of antipsychotic substances dates back to the 1960s, when researchers found that these compounds act as dopamine receptor antagonists. Unfortunately, this type of drugs cannot block the D2 receptors only in the mesolimbic dopaminergic pathway (which mediates their therapeutic effects), because of their non-selective D2 receptor blockage in both the mesolimbic and striatal regions, and the consequent appearance of side effects related to striatal interaction in the same dosage range as is needed for the therapeutical effects. ⋯ Later, other beneficial properties, such as improvement of negative symptoms and of cognitive dysfunction and efficacy in neuroleptic-resistant schizophrenia, were included in the definition of "atypical". In recent years, the appearance of new atypical antipsychotics (risperidone, olanzapine, quetiapine, ziprasidone) has opened new ways to therapy. The aim of this paper is to review literature about newer antipsychotics, focusing on their advantages in terms of efficacy and side effect profiles when compared to classical and older atypical antipsychotics, and to evaluate the efficacy of the different new antipsychotics when compared to one another.
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Review Comparative Study
Pharmacological approaches in the treatment of atrial fibrillation.
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with substantial cardiovascular morbidity and mortality. The arrhythmia can be initiated and/or maintained by rapidly firing foci, single- and multiple-circuit reentry. Once initiated, AF alters atrial electrical and structural properties (atrial remodeling) in a way that promotes its own maintenance and recurrence and may alter the response to antiarrhythmic drugs. ⋯ The recent finding that angiotensin converting enzyme inhibitors and beta-blockers reduce the incidence of AF in patients post myocardial infarction with left ventricular dysfunction confirmed the importance of targeting the underlying arrhythmogenic substrate. This review focuses on the mechanisms underlying AF and the mechanism of action and the efficacy and safety profile of the ADs used in the treatment of atrial fibrillation. The advantages and disadvantages of rhythm and rate control, the role pill in a pocket concept and the role of the new ADs are dicussed.
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Although great progress has been made in our understanding of the molecular bases of mitochondrial disorders due to defects in the respiratory chain, little exists in the way of rational therapy. Possible therapeutic approaches include: palliative therapy; removal of noxious metabolites; administration of artificial electron acceptors, metabolites, and free radical scavengers; genetic counseling; and gene therapy. There has been progress with each of these approaches, although much work remains to be done. Finally, a novel approach to treating a specific mitochondrial disorder, MELAS, is presented.
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Calcium (Ca(2+)) ions are the currency of heart muscle activity. During excitation-contraction coupling Ca(2+) is rapidly cycled between the cytosol (where it activates the myofilaments) and the sarcoplasmic reticulum (SR), the Ca(2+) store. These fluxes occur by the transient activity of Ca(2+)-pumps and -channels. ⋯ These compounds, which increase intracellular cAMP-levels, have failed in clinical trials. Therefore medical researchers are seeking new drugs that act through alternative pathways. Novel cardiac inotropes targeting SR Ca(2+)-cycling proteins may have the potential to fill this gap.
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The classical model of the coagulation cascade is to be replaced by a new, cell based model of coagulation emphasizing the interaction of coagulation proteins with cell surfaces of platelets subendothelial cells and the endothelium. According to current knowledge hemostasis is initiated by the formation of a complex between tissue factor (TF) exposed as a result of a vessel wall injury, and already activated factor (F) VII (FVIIa) normally present in the circulating blood. The TF-FVIIa complexes convert FX into FXa on the TF bearing cell. ⋯ Recombinant coagulation factor VIIa (rFVIIa; NovoSeven(R)) was originally developed and approved for the treatment of bleeding episodes and the prevention of bleeding during surgery in hemophilia patients with inhibitors and in patients with auto-antibodies against FVIII or FIX (acquired hemophilia). As rFVIIa in pharmacological doses enhances thrombin generation on activated platelets, it has been suggested that rFVIIa may also help to improve hemostasis in other situations involving impaired thrombin generation. This is substantiated by the accumulation of published data indicating that rFVIIa is able to control bleeding in patients with thrombocytopenia or platelet function deficiencies as well as in patients without pre-existing coagulopathies.