Bile-acid sequestrants with ezetimibe

Renal function impairment For patients with severe renal insufficiency, do not start ezetimibe/simvastatin unless the patient has already tolerated treatment with simvastatin at a dose of 5 mg or higher. Exercise caution when ezetimibe/simvastatin is administered to these patients, and monitor them closely. Concomitant bile acid sequestrants Give ezetimibe/simvastatin either 2 hours or more before or 4 hours or more after administration of a bile acid sequestrant. Concomitant cyclosporine Exercise caution when initiating ezetimibe/simvastatin in the setting of cyclosporine. In patients taking cyclosporine, do not start ezetimibe/simvastatin unless the patient has already tolerated treatment with simvastatin at a dose of 5 mg or higher. Do not exceed 10 mg ezetimibe/10 mg simvastatin daily. 

Ann Jeina was treated with a statin (pravastatin) and cholestyramine, a bile acid sequestrant. With the introduction of the cholesterol absorption blocker ezetimibe, the use of cholestyramine with its high level of gastrointestinal side effects may decline. Ezetimibe reduces the percentage of absorption of free cholesterol present in the lumen of the gut and hence the amount of cholesterol available to the enteroc5de to package into chylomicrons. This, in turn, reduces the amount of cholesterol returning to the liver in chylomicron remnants. The net result is a reduction in the cholesterol pool in hepatocytes. The latter induces the synthesis of an increased number of LDL receptors by the hver cells. As a consequence, the capacity of the liver to increase hepatic uptake of LDL from the circulation leads to a decrease in serum LDL levels. 

Coadministration with bile acid sequestrants Dosing of ezetimibe should occur at least 2 hours before or at least 4 hours after administration of a bile acid sequestrant. 

An opposite effect is at the basis of the up-regulation of LDL receptors in response to treatments with bile acid sequestrants, intestinal cholesterol absorption inhibitors, and HMG-CoA reductase inhibitors. The first class of drugs inhibits the intestinal reabsorption of bile acids, thus promoting increased conversion of cholesterol to bile acids in the liver. The increased demand for cholesterol results in activation of the SREBP system and upregulation of LDL receptor synthesis (as well as cholesterol synthesis via upregulation of HMG-CoA reductase). Similarly, inhibition of intestinal cholesterol absorption with ezetimibe results in a reduction in the hepatic cholesterol pool... 

The primary goal of therapy is the control of the hypercholesterolemia and prevention of atherosclerotic cardiovascular disease. Patients with heterozygous FH can usually be successfully treated with medications to lower the LDL cholesterol to acceptable levels (Table 14-2). They are generally responsive to treatment with statins, alone or in combination with other drugs, such as bile acid sequestrants (such as cholestyramine) or cholesterol absorption inhibitors (such as ezetimibe) that act additively to upregulate the expression of the functioning LDL receptor as described in the Biochemical Perspectives section. In a few cases, a more aggressive treatment with LDL apheresis (discussed in this section) may have to be considered in order to reach acceptable LDL cholesterol levels. 

All HMGRIs are approved for the treatment of primary hypercholesterolemia and familial combined hyperlipidemia (Fredrickson s type Ha and lib) (Table 30.2) In patients who have not responded to diet, exercise, and other non pharmacological methods (Table 30.6) (15,21). They may be used either alone or In combination with bile acid sequestrants, ezetimibe, or niacin. As previously mentioned, they should be administered at least 1 hour before or 4 to 6 hours after bile acid sequestrants when this combination Is desired. Fluvastatin, lovastatin, pravastatin, and simvastatin have been specifically Indicated to reduce the mortality of CHD and stroke. By reducing plasma LDL levels, these compounds slow the progression of atherosclerosis and reduce the risk of myocardial Infarction and other ramifications of vascular occlusion. Atorvastatin, rosuvastatin, and simvastatin have been shown to be effective In homozygous familial hyperlipidemia and are Indicated for this use. Additionally, atorvastatin, pravastatin, and simvastatin are Indicated for primary dysbetallpoprotelnemla (Fredrickson s type III) (Table 30.2). Finally, atorvastatin, pravastatin, rosuvastatin, and simvastatin are Indicated for the treatment of hypertriglyceridemia. 

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