Donepezil caused the urinary urgency that oxybutynin then treated, and oxybutynin's anticholinergic effect on memory brought a higher donepezil dose; this NU553 Unit 7 analysis breaks the loop at its origin. Searches like "nu 553 unit 7 assignment example", "nu553 unit 7 sample" and "nu553 unit 7 example" land here.
Donepezil, Then Oxybutynin, Then More Donepezil: A Prescribing Cascade Traced Back to Its First Entry
[Student Name]
Purdue University Global
NU553: Advanced Pharmacology and Pharmacotherapeutics
Unit 7 Prescribing Cascade Analysis
[Instructor Name]
[Date]
The patient and prescribers are composites; no real person is described, and no individual is blamed.
The Timeline
1. [March]: donepezil 5 mg nightly started by a memory clinic for mild Alzheimer disease.
2. [April]: dose increased to 10 mg nightly, per the usual titration.
3. [May]: new urinary urgency, frequency and two episodes of leaking before reaching the bathroom. She mentions it at a primary care visit.
4. [June]: oxybutynin immediate release 5 mg twice daily prescribed by a covering primary care clinician for overactive bladder.
5. [July to August]: dry mouth, constipation and, her daughter reports, more forgetfulness and one evening of confusion.
6. [September]: at a memory clinic follow-up, her cognitive score has fallen. Donepezil is increased to 23 mg daily for apparent progression.
Mrs. [H.], 73, has type 2 diabetes and hypertension and had no urinary symptoms before March.
Test 1: Timing
A prescribing cascade occurs when one drug's side effect is read as a fresh diagnosis and a second drug is prescribed for it (Rochon & Gurwitz, 1997). The first test is whether the timing fits. Urinary symptoms appeared about two months after donepezil started and within weeks of the dose increase, with no symptoms before. Cognitive worsening followed oxybutynin by one to two months. Both sequences fit.
Test 2: Pharmacological Plausibility
Donepezil inhibits acetylcholinesterase, raising acetylcholine levels. The intended target is the brain, but acetylcholine acts throughout the body. At the bladder, it stimulates muscarinic receptors on the detrusor muscle, which contracts to empty the bladder. More acetylcholine can mean more frequent and more urgent contractions, producing urgency and incontinence. Cholinesterase inhibitors are recognized causes of urinary incontinence, and older adults who start one are more likely to be prescribed an anticholinergic bladder drug soon afterward (Gill et al., 2005).
Oxybutynin blocks muscarinic receptors. It is not selective for the bladder, and it crosses the blood-brain barrier readily. In the brain, it opposes the very effect donepezil was prescribed to produce. The two drugs are pharmacological opposites, and taking both means each partly cancels the other. Strongly anticholinergic drugs impair memory and attention in older adults and can cause confusion, and in a cohort study, heavier cumulative use went with more incident dementia (Gray et al., 2015). Dry mouth and constipation, which she also developed, are classic anticholinergic effects. The Beers Criteria list strong anticholinergics among the drugs to keep away from people living with dementia and flag the combination of a cholinesterase inhibitor with an anticholinergic (American Geriatrics Society Beers Criteria Update Expert Panel, 2023).
Test 3: Was the Symptom Met With a New Prescription?
Yes, twice. The third test asks whether the response to a new symptom was a second prescription rather than a review of the first. In June, urinary urgency was treated with oxybutynin without the question of whether donepezil had caused it. In September, cognitive decline was treated with a higher donepezil dose without the question of whether oxybutynin had caused it.
Each clinician acted reasonably on the information in front of them. The covering primary care clinician saw a 73-year-old woman with new urgency, a common and treatable condition. The memory clinic saw a lower cognitive score in a woman with Alzheimer disease, a condition expected to progress. Neither saw the whole sequence, and the medication list at each visit showed the drugs without the dates they started or the reasons they were added.
What the September Score Could and Could Not Show
The memory clinic's decision in September rested on a fall in her cognitive score. A single score is a snapshot, and several things other than disease progression can lower it: a drug with central anticholinergic effects, poor sleep, constipation, an infection, low mood or simply a bad day. Alzheimer disease usually progresses slowly, over years, and a clear drop over six months in a woman with mild disease should prompt a search for a reversible cause before it is attributed to the illness. The daughter's report of one evening of confusion in August is itself a warning sign, since fluctuating attention points toward delirium, often drug-related, rather than steady decline.
Raising donepezil to 23 mg also has a cost. The higher dose offers at most a small additional cognitive benefit over 10 mg, with more nausea, vomiting and weight loss, and in her case it would increase the very cholinergic stimulation of the bladder that started the sequence. Had the dose increase stood, the next visit might well have brought a complaint of worse urgency, and a stronger bladder drug.
The Proposal
The order follows the pharmacology: remove the drug that most clearly harms, wait for recovery, then reconsider the rest.
1. Stop oxybutynin now. It has the clearest harm, it opposes donepezil and it is on the list of drugs to avoid in dementia. Immediate-release oxybutynin can be stopped without tapering.
2. Return donepezil to 10 mg. The increase to 23 mg was made in response to an apparent decline that oxybutynin may explain, and the higher dose carries more gastrointestinal and cholinergic effects, including, potentially, more urinary urgency.
3. Reassess cognition in six to eight weeks. If her score returns toward its earlier level after oxybutynin is gone, the September decline was drug-induced.
4. Reassess the urinary symptoms at the same visit. If urgency persists on donepezil 10 mg, consider whether the benefit of donepezil justifies it, a conversation with Mrs. [H.], her daughter and the memory clinic.
Managing the Urgency Without Oxybutynin
The original problem still needs attention. Behavioral measures come first: scheduled voiding every two to three hours, reducing evening fluids and caffeine, and pelvic floor exercises if she can learn them. Her daughter can help with a toileting schedule. A urinalysis and a check of her blood glucose would exclude an infection or glycosuria contributing to frequency.
If medication is needed, the alternatives have their own limits. Mirabegron, a beta-3 agonist, relaxes the detrusor without anticholinergic effects but can raise blood pressure, which matters with her hypertension. Trospium, an anticholinergic that crosses into the brain less readily, still carries anticholinergic effects elsewhere. Either choice would be made with the memory clinic's knowledge.
Preventing the Next Cascade
Two changes would make this cascade less likely to recur. A medication list that shows start dates and the reason for each drug lets the next clinician line a complaint up against the drug that preceded it. And a note in her record, "urinary urgency possibly due to donepezil; avoid anticholinergics," carries the lesson to clinicians who were not part of this sequence.
References
American Geriatrics Society Beers Criteria Update Expert Panel. (2023). American Geriatrics Society 2023 updated AGS Beers Criteria for potentially inappropriate medication use in older adults. Journal of the American Geriatrics Society, 71(7), 2052-2081. https://doi.org/10.1111/jgs.18372
Gill, S. S., Mamdani, M., Naglie, G., Streiner, D. L., Bronskill, S. E., Kopp, A., Shulman, K. I., Lee, P. E., & Rochon, P. A. (2005). A prescribing cascade involving cholinesterase inhibitors and anticholinergic drugs. Archives of Internal Medicine, 165(7), 808-813. https://doi.org/10.1001/archinte.165.7.808
Gray, S. L., Anderson, M. L., Dublin, S., Hanlon, J. T., Hubbard, R., Walker, R., Yu, O., Crane, P. K., & Larson, E. B. (2015). Cumulative use of strong anticholinergics and incident dementia: A prospective cohort study. JAMA Internal Medicine, 175(3), 401-407. https://doi.org/10.1001/jamainternmed.2014.7663
Rochon, P. A., & Gurwitz, J. H. (1997). Optimising drug treatment for elderly people: The prescribing cascade. BMJ, 315(7115), 1096-1099. https://doi.org/10.1136/bmj.315.7115.1096
How this NU553 Unit 7 example is structured
Three tests organize the analysis, applied in sequence: timing, pharmacological plausibility, and whether the response to the symptom was a second prescription rather than a review of the first. The timeline settles timing at a glance. Pharmacology settles plausibility, tracing the urgency to increased cholinergic tone at the bladder's muscarinic receptors and the later confusion to oxybutynin's blockade of the same receptors in the brain. The third test is shown through prescriber roles, since each clinician acted reasonably on the information in front of them and none saw the whole sequence. The proposal is ordered by pharmacology too: remove the drug that most clearly harms, wait for recovery, then reconsider what remains. The urgency still needs managing, so the plan offers behavioral measures and names alternatives with their own limits rather than leaving the original problem untreated.
Get an NU553 Unit 7 example written to your instructions
Upload the timeline or medication history your NU553 Unit 7 case provides, along with its directions and rubric; any cascade works, not only this one. In 24-48h, with the first one free, the sample lays the months on one line, tests timing and plausibility, names the step where the cascade closed, and orders the undoing by pharmacology. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
NU553 Unit 7 questions, answered
How is a cascade different from an ordinary side effect?
The difference lies in what happens next: an adverse effect turns into a cascade once someone reads it as fresh illness and prescribes for it. The original agent stays, the new one adds its own risks, and sometimes, as here, the second drug's effects prompt more of the first. The analysis earns credit by naming the moment the symptom was treated instead of the cause reviewed.
Should the analysis diagnose the patient with Parkinson disease or not?
It should say the diagnosis is uncertain until the suspected drug has been withdrawn and enough time has passed. Drug-induced parkinsonism often improves after the offending agent stops, though recovery can take months. An analysis that keeps both possibilities open, with a reassessment date, is more defensible than one that settles the question too early in either direction.
What alternatives for gastroparesis can the plan name?
The sample names dietary changes, such as smaller and lower-fat meals, and mentions that other prokinetic options carry their own limits, including availability and interactions. It brackets any agent and amount as composite and routes the choice to the prescriber managing her diabetes. A plan that removes the cause of the cascade still owes the patient a way to manage the original symptom.