Are You Caught in a Prescribing Cascade?
The other day when I was reading through some posts on the Heart-Failure.Net Facebook community page, I came across a comment that caught my attention:
“Crazy that doctors keep prescribing medicine that counteracts each other...they prescribe medication to offset the side effects of another...no wonder our bodies are such a mess!”
The author of this post identified a significant issue, with potentially disastrous consequences, that can arise when a new therapy is prescribed. The phenomenon where a drug is prescribed to treat the side effect(s) of another drug is a very common occurrence in medicine. In fact, it is so common that there is a term for it: a prescribing cascade.
What is a prescribing cascade?
A prescribing cascade is when a side effect of a medication is misdiagnosed as a new medical condition and is treated with a new drug that may be unnecessary.1 People who are at risk of prescribing cascades include older adults and people on multiple medications, such as people with heart failure.
Example of a prescribing cascade
Calcium channel blockers, such as amlodipine and nifedipine, are common medications prescribed in heart failure. These drugs help lower blood pressure and heart rate. However, one common side effect of these medications is peripheral edema, also known as swelling of the lower legs and hands. 20-30% of people can experience this side effect.2 Furthermore, this side effect is dose-dependent, meaning that higher doses of the calcium channel blocker cause more swelling.
Sometimes when someone presents with this peripheral edema side effect, they are prescribed another agent such as a diuretic like furosemide. However, this medication doesn’t tend to improve the edema because the edema is a result of fluid redistribution rather than fluid overload. Rather, it may cause harm to those without fluid overload.3 The effective way to treat edema caused by calcium channel blockers is to switch to another blood pressure medication or reduce the dose.
How often does this occur?
A study that analyzed 40,000 people with high blood pressure found that 1.7% of them who were prescribed a calcium channel blocker were also prescribed a loop diuretic within 90 days. This is compared to 0.7% of people subsequently prescribed loop diuretics but were initially prescribed a different blood pressure medication.3
Be your own advocate
What can you do to prevent such a situation from occurring to yourself? The key is to be your own advocate. Read the information sheet you receive from any new medication you are prescribed or ask your pharmacist what side effects you may experience. Keep a journal of how you feel when you start new medications; it is best to couple this with vital readings, if appropriate.
From your clinician's standpoint, it is important that you get a periodic review of all your medications. Reviewing your medications every so often can facilitate changes, such as discontinuing a drug you no longer need or switching to a different drug that is better tolerated.
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