Breastfeeding & Zyrtec

Breastfeeding an infant can make anyone anxious about the medicines and other chemicals that might transfer from mother to baby. It is wise to check with a physician or other healthcare professional about medicines taken regularly. While Zyrtec can help allergy sufferers with their allergy symptoms, there are questions about whether or not it is acceptable to take while breastfeeding.

Zyrtec's Function

According to Drugs.com "Zyrtec is an antihistamine that reduces the natural chemical histamine in the body." Its scientific name is cetirizine. While it has not been shown to harm unborn babies, Drugs.com says there is evidence of transmission from mother to child in breast milk with harmful results since the drug is not recommended for children under the age of six months.

Breastfeeding and Medication

When a woman breastfeeds, her milk is infused with the chemicals, vitamins and minerals she puts in her body. This includes whatever medicines the mother may take. Some medications have been deemed safe, meaning the amounts transmitted through the breast milk are not harmful to a breastfeeding child. However, others have not been deemed safe and should be discontinued while nursing.

Problems with Determining Drug Safety

One of the problems determining which drugs are safe and which are not is the limited way in which they are tested. Although all drugs must undergo testing before getting FDA (Food and Drug Administration) approval and becoming commercially available, according to CDC.gov, "For ethical reasons, pregnant and breastfeeding women are usually not included in these studies. As a result, little information is available about the safety of most medications during pregnancy or breastfeeding when they are first marketed."

Animal Testing

RxList.com reports some side effects from Zyrtec in the nursing young of animals given the drug. According to the site, mice given "40 times the maximum recommended daily oral dose in adults" passed the medication along to their young through nursing. The young experienced a decrease in weight gain.
Additionally, tests on beagles showed a transmission rate of 3 percent from mother to young. The site cautions that animal testing results are not always truly analogous to results in humans. However, because of a dearth of testing in nursing women and their children, it is safer to assume that the drug should not be taken while breastfeeding.

Tests in Infants

Clinical trials of Zyrtec have been conducted in children of common breastfeeding age (6 to 24 months). These children were given dosages directly; not through the medium of breast milk. Some side effects were discovered, but according to RxList.com, side effects like sleeplessness and irritability experienced by the group receiving Zyrtec did not vary greatly from those experienced by a group given a placebo.