Your Next Prescription Could Be Treating a Side Effect From Your Last One, Study Finds

A large study across Ontario, Canada, has found that widely used medications, including statins and iron supplements, can sometimes trigger a chain of additional prescriptions in older adults. The research, published in the journal BMJ, was led by Dr. Paula Rochon, director of research at the Weston and O'Born Center for Mature Women's Health at Sinai Health in Toronto.

The pattern is known as a potentially inappropriate prescribing cascade: a side effect from one medication is mistaken for a separate health problem, leading to another prescription that may not have been necessary. One example involves NSAIDs (non-steroidal anti-inflammatory drugs), commonly used for pain, which are associated with increases in blood pressure; if that change is treated as new high blood pressure, a patient may receive another medication instead of having the original pain treatment reconsidered.

Older adults are especially susceptible because they are more likely to have multiple health conditions and take several medications at once, making it harder for clinicians and patients to tell whether a new symptom stems from an existing prescription. Rochon said knowing what medications a patient takes, when they were started and for what reason is important for identifying these problematic sequences, which are common but often missed in clinical practice.

The project, involving experts from the United States, Belgium, Italy, Israel and Ireland alongside the Sinai Health team, built on earlier work identifying 65 potentially inappropriate prescribing cascades. Comparing that list against population-level prescription data from ICES, Ontario's health data institute, researchers identified 24 cascades that were both common and potentially harmful.

The findings may be especially relevant for mature women, who tend to experience more chronic conditions, receive more drug therapies and have more adverse drug events over their lifetimes. Researchers say automated clinical decision-support systems and a greater role for pharmacists in prescribing decisions could help catch these cascades before an unnecessary medication is added.