Tool predicts drug combinations that impair birth control

Researchers have developed a computer model that identifies drug combinations that could reduce contraceptive effectiveness.

Many contraceptive users may not realize that taking additional medications can reduce the effectiveness of birth control, resulting in an unintended pregnancy.

in the magazine Clinical pharmacology and therapeuticsIn the study, the researchers describe how they developed a computer model and validated the results in real-world data to compare hormonal contraceptive products when taken alone or with other drugs.

The model will help regulators, as well as the pharmaceutical industry, assess best and worst case scenarios Hormonal contraceptives With new drug candidates.

There is an urgent public health need to understand how drug interactions play out unplanned pregnancyStefan Schmidt, professor at the University of Florida College of Pharmacy and director of the Center for Pharmaceutical Measurements and Systems of Pharmacy says. “We have more than 300 million women worldwide who are exposed to these drug interactions, and evidence suggests that the failure rate is as high as 50% in low- and middle-income countries.”

Contraceptive failure rates are lower in the United States than in sub-Saharan Africa and countries where prevalent diseases, such as HIV and tuberculosis, require multiple medications. Women who take these drugs are at risk of unintended pregnancy because the HIV and TB drugs stimulate CYP3A4, an enzyme that helps release the progestins found in hormonal contraceptives into the bloodstream.

“It’s the scenario in which one drug can change the speed at which the body gets rid of the other drug,” Schmidt says. “If drug concentration levels drop faster than intended, birth control medications are at an increased risk of being ineffective at preventing pregnancy.”

Researchers examined several hormonal contraceptives – designed with different ingredients – to determine the risks of drug interactions causing unplanned pregnancies. In the best case scenario, they find that oral hormonal contraceptives are 100% effective, however, this rate of effectiveness can be diminished by various factors without the use of secondary protection.

The upper and lower limits were generated using a computer-aided modeling approach called pharmacokinetic arcs. The researchers developed the model to simulate and evaluate drug interactions that may not be studied frequently in the real world. Using real-world data, researchers compared the rate of unwanted pregnancy among women using different hormonal contraceptives who experienced drug interactions.

“Our main goal was to provide a development framework for drug regulators and the pharmaceutical industry to use when evaluating and developing new drug products,” said Brian Sekal, assistant professor of pharmacology at the University of Florida College of Pharmacy and co-lead author of the study with Amir Sarayani and Lais da Silva.

“Defined thresholds for hormonal contraceptives will aid the development of new formulations to improve drug access and use in low- and middle-income countries.”

This research supports ongoing global drug development and regulatory evaluation efforts led by the departments of Pharmacy, Pharmaceutical Outcomes, and Policy at the university’s College of Pharmacy and with support from the Bill & Melinda Gates Foundation. In addition, Bayer has served as an industrial collaborator on research efforts, directed modeling, and clinical pharmacology for its compounds.

source: University of Florida