Evaluate the plasma triglyceride concentration four weeks after beginning a reduced-fat diet. If the reduction in triglycerides
is inadequate, ask the owner about compliance (e.g. excess or inappropriate treats, access to other foods), reevaluate the diet's fat content, and reevaluate the medical record
to ensure other diseases were ruled out (especially hypothyroidism and hyperadrenocorticism). For patients with poor response
to low-fat commercial diets, consultation with a nutritionist for a balanced ultra-low-fat home-cooked diet may be beneficial.
When low-fat diets are not adequate, lipid-reducing pharmacologic agents can be considered.
Pharmacologic intervention. Lipid-lowering agents used in people include chitosan, omega-3 fatty acids, niacin, fibric acid derivatives, and statins.18 Evidence for their effectiveness and safety in veterinary medicine is lacking.
Chitosan is a calorie-free, animal-derived fiber supplement that not only passes through the intestines without being digested
but also absorbs and removes fat.19 There are no clinical trials reporting the benefit or side effects of chitosan.
Diets rich in omega-3 fatty acids can lower hypertriglyceridemia in people by decreasing the production of VLDLs.18 Menhaden oil can be used in dogs at a dosage of 200 mg/kg/day.3,10
Niacin (100 mg/day in dogs) may also reduce hypertriglyceridemia by decreasing fatty acid release from adipocytes and reducing
the VLDL production.3,10 Potential side effects of niacin include erythema, pruritus, abnormal hepatic function test results, vomiting, and diarrhea.3,10 In our experience, these side effects and the lack of convincing evidence of efficacy limit niacin use in dogs and cats.
Fibric acid derivatives lower triglycerides by stimulating lipoprotein lipase, which decreases the production of fatty acids
and, in turn, reduces VLDL concentrations.18 We commonly use gemfibrozil (Lopid—Pfizer) at a dosage of 200 mg/day in dogs and 10 mg/kg every 12 hours in cats.3,10 Potential side effects include abdominal pain, vomiting, diarrhea, myositis, and abnormal hepatic function test results.3,18
The statins can be used to lower VLDLs, LDLs, and HDLs in people.18 Statins are usually prescribed for hypercholesterolemia in people; however, they are modestly effective at lowering triglyceride
concentrations.18 Adverse effects in people include lethargy, diarrhea, muscle pain, and hepatotoxicity. Because of these potential side effects
in dogs and cats and the lack of convincing efficacy in lowering triglyceride concentration, we rarely use statins to treat
Treatment of hypercholesterolemia relies largely on diet and occasionally on pharmacologic intervention. As mentioned previously,
dogs and cats transport most of their cholesterol as HDLs, minimizing the risk of atherosclerosis. Thus, we do not recommend
treating hypercholesterolemia until the concentration is above 750 mg/dl in dogs or 650 mg/dl in cats because of the likely
increase in LDL that may predispose them to atherosclerosis at these concentrations.9 As with hypertriglyceridemia, the search for secondary causes is a must. In our experience, severe hypercholesterolemia
in cats is rarely encountered and in dogs is usually secondary to hypothyroidism.
Dietary modification. For severe idiopathic hypercholesterolemia, low-fat diets are the mainstay of therapy.3 In addition, soluble fiber (gums, pectins) can be added to diets to help decrease the cholesterol concentration.19 Soluble fiber interferes with the enteric absorption of bile acids and increases the hepatic use of cholesterol to synthesize
Pharmacologic intervention. For those patients unresponsive to diet alone, bile acid sequestrates and statins may be considered.