Low birth weight babies, whose organs are often underdeveloped, may face lifelong difficulties in metabolizing medications, which can complicate the treatment of illnesses they might encounter in the future. A new study from researchers at Oregon Health & Science University and Oregon State University is the first to implicate low birth weight as a permanent factor in drug response.
When more fully understood, low birth weight may be added to the list of factors already being considered in medication dosages, such as age, weight, gender and ethnicity. Some of that is already being done in infants. But right now it's not one of the factors considered in adults, scientists say, and more work needs to be done before such consideration is warranted.
"Low birth weight affects the development of organs, as the fetus tries to finish development of the brain and, in a sense, sacrifice as necessary the ordinary development of organs such as the kidney," said Ganesh Cherala, an assistant professor in the OSU/OHSU College of Pharmacy, in a statement. "But the kidney is one of the primary filtering agents in the body, and is directly involved in drug elimination."
The kidneys of low birth weight individuals have a significantly impaired ability to filter and excrete foreign compounds, Cherala said. Since the biologic impact of a medication is affected by its absorption, metabolism and excretion, low birth weight individuals might be less able to excrete drugs.
However, the biologic processes are not that simple, Cherala said. Because of liver metabolism and other issues, in many cases low birth weight individuals end up having less response to a drug, instead of more.
"A pain killer, for instance, might end up being metabolized in the liver instead of making its way to the brain where it is supposed to function," Cherala said. "You might need more of that same drug in a low birth weight individual to have the same effect."
The complexities of these processes need additional study before recommendations could be made to alter drug dosages based on low birth weight status, Cherala said. But this issue could be important and should be further explored, he said.
Image: Prescription medication, via Shutterstock