As if severely overweight people didn't already have enough health concerns, experts are raising another red flag - the possibility that some of their prescription medications, especially antibiotics, may not be prescribed at the appropriate dosage and could be ineffective.
Because most adult antibiotics are produced in a “one size fits all” dosage and some doctors are not attuned to this issue, the societal trend towards severe obesity is resulting in more individuals who get inappropriate drug therapies for infectious disease, a new study in the journal Pharmacotherapy suggests.
“The number of individuals with the highest body mass index, very obese people, is up 600 percent between 1986 and 2000,” said David Bearden, a clinical associate professor in the College of Pharmacy at Oregon State University.
“Very obese individuals in some cases, even those with severe infections, may be getting only half the necessary dose of a prescription drug such as an antibiotic,” Bearden said. “That's a problem. It could lead not only to antibiotic failure but also an increase in antibiotic resistance, another serious issue.”
The problem is somewhat less of a concern with dosages of medications that patients take for extended periods, such as blood pressure or cholesterol medications, because the results of taking those medications are more routinely monitored and dosages can be increased as necessary. It's a particular concern with antibiotics, Bearden said, because they are often used to treat severe or even life-threatening infections, and “bad things can happen quickly if the drug is ineffective.”
Drug companies are just now becoming more aware of this issue and beginning to test and recommend dosages more appropriate for adults of varying weights, Bearden said. But with older drugs that are commonly used, there often is very little or no data for adjusting dosages. In actual practice the issue is often ignored outright, or “educated guesses” are made with whatever data is available.
Without more attention, the issue may only get worse, and it's not just a U.S. phenomenon. The World Health Organization estimates that 400 million people were obese in 2005 and that the total will increase to 700 million by 2015. It considers these numbers a “global pandemic” that is affecting low, middle and high-income nations around the world. Obesity is also considered an independent risk factor for surgical site infections and is associated with higher mortality rates in critically ill patients.
Even if the problem is carefully considered, Bearden said, it's not simple.