The Food and Drug Administration (FDA) has approved mipomersen sodium subcutaneous injection (Kynamro) for the treatment of homozygous familial hypercholesterolemia (HoFH), a rare inherited condition that prevents the body from removing low-density lipoprotein (LDL) cholesterol, the so-called "bad" cholesterol, from the blood. Patients with HoFH have severely elevated LDL cholesterol levels and elevated risks of heart attack and death before the age of 30. Patients with HoFH also have elevated levels of apolipoprotein B, total cholesterol, and non-high-density lipoprotein cholesterol, which are lipid particles that give rise to LDL cholesterol. Mipomersen sodium is injected weekly as part of a regimen with other lipid-lowering drugs and diet.

Mipomersen sodium's label carries a boxed warning that the drug increases the risk of hepatotoxicity. It can increase the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). It also increases hepatic fat (hepatic steatosis), which can occur whether or not ALT and AST levels are elevated. Hepatic steatosis is a risk factor for progressive liver disease (steatohepatitis and cirrhosis). If the ALT or AST level is equal to or greater than three times the upper limit of normal, mipomersen sodium should be withheld. If the patient demonstrates clinically significant liver toxicity, the drug should be discontinued.

The vast majority (84%) of patients using mipomersen sodium will develop injection-site reactions (erythema, pain, tenderness, pruritus, and local swelling). Thirty percent will develop flulike symptoms (high fever, chills, muscle aches, arthralgia, malaise, or fatigue) within two days after an injection. Elevations in ALT and AST levels are also common but aren't necessarily substantial enough to indicate hepatoxicity.

Nurses providing education regarding mipomersen sodium should teach subcutaneous injection technique using the prefilled syringe that will be dispensed by the pharmacy. The medication should be at room temperature prior to administration. Nurses should emphasize the importance of returning for blood work to allow liver-function monitoring and assessment of cholesterol levels.

To read the FDA news release regarding mipomersen sodium, go to http://1.usa.gov/T79wQI.