Immunoglobulins
The only immunoglobulin in the antilipemic class is evolocumab (Repatha), which has no human pregnancy data. It is an immunoglobulin G2 that is indicated as an adjunct to diet and maximally tolerated statin therapy. It is also indicated as an adjunct to diet and other low-density lipoprotein–lowering therapies in patients with homozygous familial hypercholesterolemia who require additional lowering. No adverse embryo-fetal effects were observed in monkeys. Because statins are contraindicated in the first trimester, the drug, if combined with a statin, can also be classified as contraindicated. However, if the drug is used alone, the embryo-fetal risk appears to be low based on the animal data.
Monoclonal antibodies
The protein alirocumab (Praluent) is a human monoclonal antibody. It is indicated as an adjunct to diet and maximally tolerated statin therapy for the treatment of adults with heterozygous familial hypercholesterolemia or clinical atherosclerotic cardiovascular disease. There are no human pregnancy data. The animal data in rats and monkeys suggest low embryo-fetal risk. However, suppression of the humoral immune response to keyhole hemocyanin antigen was observed in infant monkeys at 4-6 months of age. The significance of this in human infants is apparently unknown. Because statins are contraindicated in the first trimester, the drug should not be used with these agents during that period.
Oligonucleotide inhibitors
No reports describing the use of mipomersen (Kynamro), an oligonucleotide inhibitor of apolipoprotein B-100 synthesis, in human pregnancy have been located. The drug is indicated as an adjunct to lipid-lowering medications and diet to reduce low-density lipoprotein cholesterol, apolipoprotein B, total cholesterol, and non–high-density lipoprotein cholesterol in patients with homozygous familial hypercholesterolemia. It has a very long (1-2 months) elimination half-life. The drug caused fetal toxicity in rats, but not in mice or rabbits.
Vitamins
Niacin is a water-soluble B complex vitamin that is converted in vivo to niacinamide. Niacin has no known embryo-fetal risk.
Miscellaneous agents
The two agents in the miscellaneous category are ezetimibe and lomitapide. Ezetimibe is indicated, either alone or in combination with a statin, as adjunctive therapy to diet for the reduction of cholesterol and triglycerides. Statins are contraindicated in the first trimester, but ezetimibe alone could be used during that period if treatment of the mother was mandated. The drug caused no problems in rabbits, but in rats, a dose 10 times the human exposure increased the incidence of skeletal abnormalities. In one report, a woman with homozygous familial hypercholesterolemia was treated with direct adsorption of lipoprotein apheresis, ezetimibe, and rosuvastatin. When pregnancy was discovered (gestational age not specified), the two drugs were stopped but biweekly apheresis was continued. At 37 weeks’ gestation, the patient gave birth to a healthy 2,400-g male infant.10
There are no human pregnancy data with lomitapide. It is indicated as an adjunct to a low-fat diet and other lipid-lowering treatments, including low-density lipoprotein apheresis where available, to reduce LDL cholesterol, total cholesterol, apolipoprotein B, and non–high-density lipoprotein cholesterol in patients with homozygous familial hypercholesterolemia. At doses less than 10 times the human dose, the drug caused congenital malformations and embryo-fetal death in rats, rabbits, and ferrets. The manufacturer classifies the drug as contraindicated in pregnancy because of the animal data.
Breastfeeding
Only niacin, pravastatin, and rosuvastatin have data regarding human milk concentrations. Niacin and its active form – niacinamide – are excreted into breast milk.
The average peak milk level in 11 lactating women given pravastatin 20 mg twice daily for 2.5 days was 3.9 mcg/L, whereas the level for the active metabolite was 2.1 mcg/L. Based on these data, a fully breastfed infant would receive daily about 1.4% of the mother’s weight-adjusted dose.11
A 31-year-old woman was treated with rosuvastatin for familial hypercholesterolemia while breastfeeding her infant. The drug was stopped during breastfeeding but was restarted at 33 days post partum. Breast milk concentrations of the drug were 1.2 times serum levels (about 22 ng/mL vs. 18 ng/mL). Unfortunately, no information was provided on the status of the nursing infant.12
Three of the above agents have high molecular weights - alirocumab, evolocumab, and mipomersen - and are probably not excreted into mature breast milk. Moreover, colesevelam is not absorbed, and very small amounts of colestipol are absorbed by mothers. Several antilipemic agents have characteristics (for example, low molecular weight or long elimination half-life) that suggest they will be excreted into breast milk: ezetimibe, fenofibric acid (active metabolite of fenofibrate), gemfibrozil, lomitapide, and all the statins.
Taken in sum, all of the antilipemics, with the exception of niacin, have the potential to cause a deficiency of fat-soluble vitamins (A, D, E, K) in mother’s milk and in the nursing infant. Deficiency is a concern for all of these vitamins, but especially for vitamin K, because it could cause bruising, petechiae, hematomas, and bleeding in the nursing infant. In addition, antilipemics could cause low levels in milk of cholesterol and lipids, which are required by a nursing infant. Consequently, they should not be used by mothers who are breastfeeding an infant.