If doctors follow UK government guidelines, they may well seriously endanger patients who have both depression and any of a variety of other common diseases or conditions such as diabetes or hypertension, according to a study in BMJ. The problem, wrote the researchers, is that polypharmacy and drug-drug interactions are not accounted for in any of the guidelines.
A Scottish-led team of researchers examined UK government guidelines for the treatment of depression, diabetes, and heart failure, and the guidelines for the treatment of a variety of other diseases or conditions that people with any of those three conditions might also have. With respect to depression and accompanying conditions, they found 89 possible dangerous drug-drug interactions that the patients might experience.
“Despite widespread multimorbidity, clinical guidelines are largely written as though patients have a single condition and the cumulative impact of treatment recommendations from multiple clinical guidelines is not generally considered,” wrote the researchers. “In people with several conditions, simply application of recommendations from multiple single disease clinical guidelines can result in complex multiple drug regimens (polypharmacy) with the potential for implicitly harmful combinations of drugs.”
In the case of people taking drugs for depression who might also be taking recommended drugs for arthritis, pain, or other common ailments, possible side effects from the drug-drug interactions included cardiovascular problems, internal bleeding, kidney failure and central nervous system toxicity.
“One of the challenges for guideline developers is that the actual harms of many drug-drug and drug-disease interactions are poorly quantified, partly reflecting that whereas clinical trials produce high quality evidence about benefit, they are poorly suited to estimating harms, particularly in real world populations in which people are typically older, frailer, have more multiple illnesses and prescribed more drugs for other conditions than trial populations,” the authors concluded. “Research is needed to more systematically quantify these harms because understanding when harms outweigh benefits is critical for rational treatment decisions(.)”
Dumbreck, Siobhan, Angela Flynn, Moray Nairn, Martin Wilson, Shaun Treweek, Stewart W. Mercer, Phil Alderson, Alex Thompson, Katherine Payne, and Bruce Guthrie. “Drug-Disease and Drug-Drug Interactions: Systematic Examination of Recommendations in 12 UK National Clinical Guidelines.” BMJ 350 (March 11, 2015): h949. doi:10.1136/bmj.h949. (Full text)