Non-optimized medication therapy, as it's called, is costing America's healthcare system anything from $495.3bn to $672.7bn a year, averaging out at around $528.4bn, say researchers at the University of California at San Diego. Just 10 years ago, the cost was around $290bn.
It encompasses everything from adverse reactions, prescription errors, non-compliance (the patient doesn't take the drugs properly) and new diseases they can create. For instance, an ACE inhibitor to lower blood pressure causes a cough that requires a cough remedy that includes an ingredient that increases blood pressure, and raises the risk of sleepiness and falls, said researcher Jonathan Watanabe.
In those cases, the drug is functioning as a new disease, said Watanabe's fellow researcher, Jan Hirsch.
Prescribing the wrong medication or the incorrect dose is another big factor that adds to these escalating costs, the researchers say, as is non-compliance, when the patient doesn't take the drug properly or even at all.
It's an avoidable cost, say the researchers, although quite how it can be reduced isn't entirely clear. One way is to use pharmacists more as a first point of contact, they say.