Cholesterol management guidelines from the American College of Cardiology/American Heart Association Task Force were last published in 2019.

View the Comparison Table: Some Lipid-Lowering Drugs

The FDA has approved the oral adenosine triphosphate-citrate lyase (ACL) inhibitor bempedoic acid for use alone (Nexletol – Esperion) and in a fixed-dose combination with the cholesterol absorption inhibitor ezetimibe (Nexlizet) as an adjunct to diet and maximally tolerated statin therapy in adults with heterozygous familial hypercholesterolemia (HeFH) or established atherosclerotic cardiovascular disease (ASCVD) who require additional lowering of LDL-cholesterol (LDL-C). Bempedoic acid is the first ACL inhibitor to be approved in the US.

Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain and altered bowel habits, often accompanied by bloating.IBS is classified according to the predominant bowel symptom as IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed type (IBS-M), or unclassified (IBS-U). Alterations in the microbiome, stress responses, sensory and motor function of the gut, and host genetic factors may be contributing factors. Since the exact cause of IBS is unknown, the goal of treatment is symptom control.

View the Table: Safety of Drugs for IBS in Pregnancy and Lactation

Diet, exercise, and weight loss can improve glycemic control, but almost all patients with type 2 diabetes eventually require drug therapy. Treating to a glycated hemoglobin (A1C) concentration of <7% can prevent microvascular complications (retinopathy, nephropathy, and neuropathy), but whether it prevents macrovascular complications and death is unclear. An A1C target of <8% may be appropriate for older patients and those with underlying cardiovascular disease (CVD), a history of severe hypoglycemia, diabetes-related complications, a limited life expectancy, or a long duration of disease.

Cholesterol management guidelines from the American College of Cardiology/American Heart Association Task Force have recently been published. See Table 1 for a brief summary of their recommendations.

View the Expanded Table: Lipid-Lowering Drugs

The goal of drug therapy for type 2 diabetes is to achieve and maintain a near-normal glycated hemoglobin (A1C) concentration without inducing hypoglycemia; the target is generally an A1C of ≤7%. Treating to this target has been shown to prevent microvascular complications (retinopathy, nephropathy, and neuropathy), but whether it prevents macrovascular outcomes is unclear. An A1C target of <8% may be appropriate for older patients and those with underlying cardiovascular disease, a history of severe hypoglycemia, diabetes-related complications or comorbidities, or a long duration of disease.

Lipid-lowering drugs should be taken indefinitely; when they are stopped, plasma lipoproteins return to pretreatment levels. HMG-CoA reductase inhibitors (statins) remain the drugs of choice for treatment of most patients who require lipid-lowering therapy.

Irritable bowel syndrome (IBS) is a common disorder characterized by chronic, intermittent abdominal pain or discomfort and altered bowel habits. It is subtyped according to the predominant bowel symptom as IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed type (IBS-M), or unclassified (IBS-U). Since the exact cause of IBS is unknown, the goal of treatment is symptom control.

Combining a statin with another drug that lowers low-density lipoprotein cholesterol (LDL-C), such as colesevelam (Welchol), niacin (Niaspan, and others), or ezetimibe (Zetia), can reduce LDL-C levels more than a statin alone, but studies convincingly demonstrating that such combinations improve clinical outcomes have been lacking. The results of a long-term randomized, double-blind clinical trial (IMPROVE-IT) recently presented at the American Heart Association's Scientific Sessions 2014 indicate that addition of ezetimibe to simvastatin in high-risk patients reduces cardiovascular events.1

IMPROVE-IT compared the efficacy of simvastatin 40 mg plus placebo with that of simvastatin 40 mg plus ezetimibe 10 mg (Vytorin) in preventing the primary endpoint, a composite of cardiovascular events (cardiovascular death, MI, hospital admission for unstable angina, coronary revascularization, or stroke) in patients with acute coronary syndrome and normal LDL-C levels (≤125 mg/dL; mean 95 mg/dL). After one year, mean LDL-C was reduced further with the addition of ezetimibe (to 53.2 vs. 69.9 mg/dL with simvastatin alone). After 7 years, 2742 events had occurred among the 9077 patients taking simvastatin plus placebo and 2572 among the 9067 taking simvastatin plus ezetimibe (event rate: 34.7% vs. 32.7%; p = 0.016). There was no significant difference between the 2 groups in noncardiovascular adverse events, including gallbladder-related events, myopathy, or cancer.

1. C Cannon et al. IMProved Reduction of Outcomes: Vytorin Efficacy International Trial. Available at www.timi.org. Accessed November 21, 2014.

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The goal of drug therapy for type 2 diabetes is to achieve and maintain a near-normal A1C concentration without inducing hypoglycemia; the target is generally an A1C of <7.0%. Treating to this target has been shown to prevent the microvascular complications of retinopathy and nephropathy, but whether it prevents macrovascular outcomes remains unclear. Three large trials found that intensive glucose control did not reduce the incidence of macrovascular events. One of these trials (ACCORD) in >10,000 patients with type 2 diabetes, with or at high-risk for cardiovascular disease, found that treating patients intensively with antihyperglycemic drugs to an A1C target of 6.0% for a mean of 3.7 years did not significantly reduce the incidence of major cardiovascular events (the primary endpoint) and was associated with increased all-cause mortality compared to patients treated to an A1C target of 7.0-7.9%. An A1C target of 7-8% may be prudent in older patients and in those with underlying cardiovascular disease, severe hypoglycemia, or multiple diabetes-related complications or co-morbidities.

HMG-CoA reductase inhibitors (statins) inhibit the enzyme that catalyzes the rate-limiting step in cholesterol synthesis. The subsequent reduction in hepatic cholesterol leads to increased expression of LDL receptors, which in turn increases uptake and clearance of LDL-C from the blood. Statins also lower very low-density lipoprotein cholesterol (VLDL-C) and triglycerides. Most statins increase high-density lipoprotein cholesterol (HDL-C), but only modestly.

The development of hyperglycemia in type 2 diabetes results from a combination of metabolic abnormalities that includes insulin resistance, diminished insulin secretion and excess hepatic glucose production. Diet, exercise and weight loss are helpful in improving glucose control, but most patients ultimately require drug therapy.

Drugs that lower low-density lipoprotein cholesterol (LDL-C) concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions. Lipid-regulating drugs must be taken indefinitely; when they are stopped, plasma lipoproteins return to pretreatment levels in 2-3 weeks.

Primary hypothyroidism is usually the result of Hashimoto's thyroiditis, thyroidectomy for hyperthyroidism, goiter or cancer, or radioactive iodine therapy for hyperthyroidism.

The National Cholesterol Education Program recommends that LDL-C be lowered to less than 100 mg/dL (2.6 mmol/L) and considers a value <70 mg/dL (1.8 mmol/L) a reasonable goal for patients at very high risk.

The development of hyperglycemia in type 2 diabetes results from a combination of metabolic abnormalities including insulin resistance, diminished insulin secretion and excess hepatic glucose production. Diet, exercise and weight loss are helpful in improving glucose control, but most patients ultimately require drug therapy.

Colesevelam (Welchol - Daiichi Sankyo - Med Lett Drugs Ther 2000; 42:102), a bile-acid sequestrant used to lower LDL cholesterol, has been approved by the FDA as an adjunct to diet and exercise in the treatment of type 2 diabetes. In unpublished studies summarized in the package insert, patients with type 2 diabetes taking metformin (Glucophage, and others), a sulfonylurea or insulin (each as either monotherapy or in combination with other anti-diabetic agents) were given colesevelam 3800 mg per day or placebo; colesevelam significantly reduced glycosylated hemoglobin (A1c) by about 0.5% more than placebo in all three trials. The mechanism is unclear.

Colesevelam can cause constipation, nausea and dyspepsia, increase serum triglyceride concentrations, and interfere with absorption of other oral drugs. One month's treatment with Welchol obtained from drugstore.com would cost about $200. Medical Letter consultants are not enthusiastic about prescribing it for this indication.

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Drugs that lower low-density lipoprotein cholesterol (LDL-C) concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions. They should not be used as a substitute for lifestyle changes; a combination of diet, exercise and lipid-lowering drugs is optimal for prevention of coronary disease. Lipid-regulating drugs must be taken indefinitely; when they are stopped, plasma lipoprotein levels return to pretreatment levels in 2-3 weeks.

Drugs that lower low-density lipoprotein cholesterol (LDL-C) concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions. In controlled trials in patients with coronary disease, some of these drugs have reduced mortality by 20% to 30%.

Vytorin, a fixed-dose combination of the cholesterol absorption inhibitor ezetimibe (Zetia - Merck/Schering Plough) and the HMG-CoA reductase inhibitor ("statin") simvastatin (Zocor - Merck), has been approved by the FDA for treatment of hypercholesterolemia. It is available as tablets containing 10 mg of ezetimibe combined with 10, 20, 40 or 80 mg of simvastatin.

The recent "PROVE IT" trial in patients with coronary heart disease showed clinical benefits associated with reducing LDL cholesterol concentrations lower than the 100 mg/dL (2.59 mmol/L) or less that had been considered optimal.

Drugs that lower low-density lipoprotein (LDL) cholesterol concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions, and also improve vasodilatation. In controlled trials in patients with coronary disease, they have reduced mortality by 30% to 40%. Lipid-regulating drugs must be taken indefinitely; when they are stopped, plasma lipid levels return to pretreatment levels in 2-3 weeks.

The FDA recently approved three new drugs for treatment of hyperlipidemia. Ezetimibe (ez et' i mibe; Zetia) is the first in a new class of drugs that inhibit intestinal absorption of cholesterol. Extended-release lovastatin (Altocor) is a new formulation of lovastatin (Mevacor, and others). Extended-release niacin plus (immediate-release) lovastatin (Advicor) is the first fixed-dose combination of lipid-lowering drugs.

New recommendations for drug treatment of hypercholesterolemia, if widely followed, will lead to a marked increase in the number of people taking lipid-regulating drugs.