Toxic Chemicals Used to Make Plastics Found in Many OTC Medications

Proton pump inhibiters, PPIs, can mask your symptoms and create new ones. (OcusFocus/iStock)

Phthalates have been linked to reproductive and developmental problems, hormonal disruptions, and even certain types of cancer.

Many people know that these are chemicals used to enhance the durability of plastics and are commonly present in various household and personal care products such as shampoo, hair sprays, and laundry detergent. Fewer people know that phthalates are a common ingredient in pharmaceuticals.

Why Are They Being Used in the First Place?

Chemists often rely on versatile phthalates to formulate different products, including pharmaceuticals, because phthalates enhance the effectiveness of certain drugs through various mechanisms.

“Pharmaceutical companies that produce gastrointestinal (GI) medications often utilize phthalates for their ability to localize medication release," an article published in the World Journal of Gastroenterology reads.

Phthalates have high compatibility with a wide range of ingredients and oils. They can also slow evaporation and give products long-term stability.

These properties make phthalates attractive for their solvent capabilities in liquid formulations and as plasticizers for plastic products and packaging, according to Homer Swei, senior vice president of Healthy Living Science for the Environmental Working Group. They can help maintain ingredient integrity, regulate the release and delivery of functional components, and enhance durability, he said.

Toxic Substances in OTC Drugs and Supplements

A 2012 study that investigated the use of phthalates as ingredients in drugs found that a wide range of prescription and over-the-counter (OTC) products and supplements from different therapeutic categories incorporate various phthalates.

The study found that phthalates are used in these products as "inactive" ingredients. Inactive ingredients in medicine are usually added to improve the efficacy of active agents, mitigate unpleasant tastes, or preserve medications until their expiration date.

While phthalates can be found in prescription and nonprescription drugs, they're very commonly used in medications designed to treat GI symptoms associated with conditions such as acid reflux. More than 20 million Americans take these drugs, known as proton pump inhibitors.

However, some medical professionals express concerns that the phthalates contained in these drugs may have adverse effects.

“Exposure to low dosages like in drugs can change gene expression by reprogramming the molecular system in cells, protein level, receptor expression, and DNA methylation,” said Dr. Luíza Mirpuri, a renowned phthalate expert. “All of these are known to influence health adversely.”

Further research is necessary to understand the extent of these potential risks fully.

Hormone-Disrupting Chemicals

Phthalates are categorized as endocrine-disrupting chemicals, which can interfere with the normal functioning of male and female hormones.

Research has established a link between phthalate exposure and male and female infertility, birth abnormalities, and cancer.

Significant apprehension regarding their effect on human health has prompted regulatory agencies in the European Union, Japan, and Canada to ban or significantly restrict the use of many types of phthalates.

Do Phthalates Cause Breast Cancer?

To explore the effects of phthalates on human health, a team of Danish researchers conducted a study to examine whether there was an association between phthalate exposure via pharmaceuticals and higher breast cancer rates.

The study's hypothesis was based on the understanding that phthalates, known for their estrogen-mimicking properties, could influence the occurrence of estrogen receptor-positive breast cancer.

In a comprehensive review involving almost 10 million women, the researchers found that women exposed to high levels of phthalates had a twofold increase in the likelihood of developing breast cancer. The study was published in the Journal of Clinical Oncology in 2019.

“Our results suggest that women should avoid high-level exposure to dibutyl phthalate, such as through long-term treatment with pharmaceuticals formulated with dibutyl phthalate,” the study's authors wrote. Dibutyl phthalate is used to enhance the flexibility and softness of plastics.

Although this study was the first to investigate the correlation between breast cancer and phthalates in drugs, its findings align with a growing body of evidence that consistently demonstrates a parallel relationship.

FDA Oversight Questioned

While the U.S. Food and Drug Administration (FDA) is widely perceived to have stringent oversight in the regulatory process for phthalate-containing drugs, a paper published in Environmental Health Perspectives notes that even though certain phthalates aren't technically approved for general use as inactive ingredients, they're allowed to be included in approved drug products with specific maximum levels.

According to the paper, OTC drugs don't require the same ingredient review as their prescription drug counterparts as long as no new ingredients are included.

And although the FDA may know the ingredients in certain drugs, manufacturers aren't obligated to disclose a complete ingredient list to the public because of patent protection laws. As a result, consumers may not know whether a particular drug contains phthalates.

According to Dr. Mirpuri, there's concern that regulatory agencies, such as the FDA, may not fully grasp the potential health risks associated with phthalates.

“They say that low-dose exposure is harmless," she said. "I find this to be unacceptable as a doctor.”

Dr. Mirpuri cited literature demonstrating that phthalates at low doses can impair male fertility and accelerate liver damage.

She drew a comparison between phthalates and DDT, an insecticide that was widely produced in the past but was banned because of its cancer-causing properties. According to her, the similarity lies in the fact that both substances weren't initially recognized as significant pollutants or contaminants. However, both can persist, accumulate, and exhibit toxic effects.

“I believe [phthalates] to be another ‘Silent Spring,’” Dr. Mirpuri said.