Therapeutic benefits of calcium channel blockers in cyclosporine-treated organ transplant recipients: blood pressure control and immunosuppression
Article Abstract:
Cyclosporine is an immunosuppressive drug administered to the majority of organ transplant patients to prevent rejection of the implanted organ. Although it is quite effective in blocking tissue graft-induced activation of the immune system (the mechanism underlying organ rejection), cyclosporine also causes hypertension (high blood pressure) and reversible toxic effects on the kidney. The hypertension may result from a direct constrictive effect of cyclosporine on the muscle tissue of the blood vessels, as well as increasing the sensitivity of this tissue to other vasoconstrictors and decreasing the perfusion of blood through the kidney (resulting in decreased fluid excretion in the urine, which can also increase blood pressure). The hypertensive effects of cyclosporine can often be controlled with calcium antagonists such as verapamil, which inhibit the uptake of calcium into vascular muscle, preventing constriction of the blood vessels; this may result from both direct and indirect actions of the antagonists. Another beneficial effect that may result from calcium antagonist administration is an enhancement of the immunosuppressive actions of cyclosporine. Laboratory tests have shown that verapamil and cyclosporine have additive effects in suppressing activation and function of human peripheral blood mononuclear cells (effector cells of the immune system). The two drugs seem to have different mechanisms of action on immune function: cyclosporine inhibits immune cell activation in a manner that is independent of calcium, whereas verapamil may exert its effects through blockade of calcium entry (although very recent experiments suggest that it may interact with neurotransmitter receptors to carry out at least part of its immunosuppressive actions). In any case, it is clear that calcium channel blockers are important therapeutic agents in reducing the adverse effects of cyclosporine on organ transplant patients. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
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Workshop IV - National Cholesterol Education Program guidelines: are they clinically relevant?
Article Abstract:
In 1987, the National Cholesterol Education Program (NCEP) published guidelines concerning the identification and treatment of patients with elevated cholesterol levels. These guidelines have been instrumental in allowing many physicians to develop a rational approach to patient care regarding cholesterol levels. Particularly helpful have been the guidelines concerning dietary approaches to the control of elevated cholesterol, and steps to take when dietary therapy fails. Full implementation of the NCEP recommendations is hindered by financial constraints: many physicians do not have time to fully educate each patient in sensible eating habits, and patients are unwilling or unable to pay for trained dieticians to help them in this regard. This often leads physicians to prescribe cholesterol-lowering drugs in place of dietary changes. The lack of accuracy in many laboratory assays for cholesterol (with variability between 10 and 12 percent) makes the therapeutically desirable change of 7 to 11 percent of the cholesterol level quite difficult to detect; it is recommended that physicians use only certified laboratories (with assay variability in the 3-to-5 percent range) for cholesterol determination. The guidelines do not adequately address the needs of some groups of patients who have special problems relating to their disease, and physicians are often left to speculate about optimal treatment for non-insulin-dependent diabetics, patients with kidney and thyroid conditions, and patients with pre-existing CAD. However, the NCEP guidelines are playing an important role in making lower cholesterol levels (and, it is to be hoped, lower rates of CAD) an attainable goal for the population at large. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
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