Popular Preterm Labor Drug Terbutaline Can Expose Brain to Pesticide Injury
by SixWise.com

Terbutaline (also known as Brethine and Bricanyl) is a drug commonly used to stop pre-term labor, prolong pregnancy and therefore prevent premature birth. About 1 million women are treated with terbutaline and related drugs every year for this purpose.

However, terbutaline is actually an asthma drug that has been approved by the Food and Drug Administration (FDA) (it was first approved in 1974) to prevent and treat wheezing and troubled breathing caused by asthma, chronic bronchitis, emphysema or other lung diseases. It works by relaxing and opening the air passages of the lungs, and it's thought that it also relaxes the muscles of the uterus during pre-term labor.

Although terbutaline is a popular pre-term labor drug, it is not FDA approved for that purpose, which means it's used "off label."

There is some controversy already surrounding the use of this drug, with some doctors believing it's an effective way to stop pre-term labor, and others concerned that it may not be safe or that it doesn't work any better than placebo. And, back in 1997, the FDA issued a letter "alerting practitioners, home health care agencies, insurance carriers, and others that continuous subcutaneous administration of terbutaline sulfate has not been demonstrated to be effective and is potentially dangerous."

Double Exposure: Terbutaline and Pesticides

However, a recent study has raised a new concern that the drug may be affecting the unborn baby's brain development. The study, published in the March 2004 issue of Toxicology and Applied Pharmacology, found that the drug might leave the brains of children especially susceptible to damage from environmental chemicals like pesticides. Specifically, rats that were exposed to terbutaline had greater brain cell damage after being exposed to the insecticide chlorpyrifos than rats not given the drug.

It had previously been suggested that children whose mothers had received terbutaline suffered from cognitive deficits, and researchers believe these findings may explain that suggestion, as the brain region damaged in the rats is known to affect learning and memory.

"Our findings suggest that exposure to drugs like terbutaline early in development can leave individuals set on a hair trigger for further problems when subsequently faced with environmental chemicals," says senior author of the study Theodore Slotkin, PhD, professor of pharmacology and cancer biology at Duke.

Slotkin also pointed out that these sensitive subgroups should be taken into consideration when safe levels of household and environmental chemicals are determined. "It is not adequate to set the allowable concentrations for certain chemicals at levels that might be unsafe for large segments of the population," he says.

Young children typically receive the highest exposures of environmental contaminants such as pesticides because they crawl on the ground and put their hands and other objects in their mouths.

Further, children consume a greater volume of food (and water) relative to their body weight, which also often contains pesticides. Alarmingly, Slotkin says that studies show virtually every school-aged child has been exposed to chlorpyrifos.

"It is increasingly clear that environmental toxicants target specific human subpopulations," says Slotkin. If your mother may have received terbutaline for pre-term labor, or if you have a child who was exposed to this drug in the womb, it's therefore especially important that you lead a "clean" lifestyle. This includes:

• Keeping your home, yard and surroundings free from pesticides, insecticides and other similar chemicals (choose chemical-free varieties from your health food store instead).

• Eating organic foods (they don't contain pesticides), including organic meats, dairy products, and eggs

• Avoiding exposure to community-wide pesticides, such as those used in mosquito fogging or farming.

• Filtering your tap water to keep out any pesticides or similar chemicals it may contain.

Recommended Reading

PA Study to Assess the Health Effects of Pesticides on Kids Halted

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Sources

Toxicology and Applied Pharmacology March 2005;203(2):154-66

Preterm Labor Drug Sensitizes Brain to Pesticide Injury

MedLine Plus: Terbutaline

FDA Office of Health Affairs

Terbutaline FAQ