At its worst, constipation can be a very serious issue in some patients and at best be a significant nuisance. Here’s a classic example of the constipation prescribing cascade.
A 72-year-old female has a history of chronic pain, urinary incontinence, hypertension, and most recently, worsening constipation requiring increasing doses of Senna-S. Her current medication list includes;
- Tramadol 50 mg BID (increased 2 months ago)
- Amlodipine 10 mg daily (increased 6 months ago)
- Aspirin 81 mg daily
- Lisinopril 20 mg daily
- Miralax 17 grams daily (added 1 month ago)
- Senna-S 2 tablets twice daily (increased 1 week ago)
- Oxybutynin 5 mg TID (start date 2 months ago)
- Chlorthalidone 25 mg daily (start date 3 months ago)
I hope you can see how timing matters in this situation. Oxybutynin is highly anticholinergic and is probably the major contributor to the constipation prescribing cascade. Recent increases in tramadol and amlodipine could also contribute to constipation issues.
Even prior to the oxybutynin, we should look at the at the change in chlorthalidone. Diuretics can exacerbate urinary frequency and may have contributed to the need for oxybutynin. This is certainly something we should discuss with the patient and consider if alternative hypertensive medication changes would be in order.
As you can see, the prescribing cascade can be dramatic and lead to several medication additions. Chlorthalidone could have lead to the oxybutynin. Oxybutynin adverse effects could have lead to the need for Senna-S and Miralax.
Whenever a new medication is added, I always look at the previous 3-6 months of medication changes to monitor for the risk of the prescribing cascade. Here’s another classic example of the prescribing cascade that may interest you.
- 30 medication mistakes PDF
- 18+ Page Drug Interaction PDF
- 10 Commandments of Polypharmacy Webinar based on my experiences in clinical practice