| Course | DNRS 6521 Advanced Pharmacology (DNP level) |
|---|---|
| Week | Week 2 |
| Paper type | Case write-up paper |
| Length | About 850 words, 6 pages |
| Format | APA 7 student paper |
| School | Walden University |
| Program | Doctor of Nursing Practice (DNP) |
| Updated | October 2026 |
Free sample paper for DNRS 6521 Week 2
Case Write-Up: Gabapentin at a Creatinine Clearance of 20 mL/min, and Why the Regimen Has to Change Around It
Student Name
College of Nursing, Walden University
DNRS 6521: Advanced Pharmacology (DNP level)
Instructor Name
Month Day, Year
Case Write-Up: Gabapentin at a Creatinine Clearance of 20 mL/min, and Why the Regimen Has to Change Around It
The Patient
A composite 81-year-old woman, 55 kg, has taken gabapentin 300 mg three times daily for postherpetic neuralgia for 2 years. It was started when her estimated glomerular filtration rate (eGFR) was 48 mL/min/1.73 m2. Since then her kidney function has declined: her serum creatinine is now 1.9 mg/dL, her eGFR by the 2021 CKD-EPI creatinine equation is 24 (Inker et al., 2021), and her creatinine clearance by the Cockcroft-Gault equation is about 20 mL/min (Cockcroft & Gault, 1976). Over 3 months she has become drowsy in the afternoons and dizzy on standing, and she fell in her kitchen last week without injury. Her pain has been well controlled. She takes no opioid.
What Falls, What Accumulates, and Over What Span
Gabapentin is not metabolized. It is excreted unchanged in the urine, and in a study across a range of kidney function, both its apparent oral clearance and its renal clearance fell in a straight line with creatinine clearance, while its half-life and peak concentration rose (Blum et al., 1994). The extent of absorption was unaffected, so the whole problem lies in elimination.
Her creatinine clearance has fallen by roughly half since the drug was started. Because clearance tracks creatinine clearance linearly, the same 900 mg daily dose now produces roughly double the average steady-state concentration it produced 2 years ago. Her half-life has lengthened in proportion, which shapes the span: each small decline in kidney function over the past months raised her exposure gradually, and each new steady state took longer to reach. That is why her symptoms arrived slowly and months after the drug was started, a pattern that can hide the cause. A case series of patients with chronic kidney disease admitted with gabapentin toxicity, most commonly altered mental status and dizziness, found that many were taking doses above those recommended for their kidney function (Zand et al., 2010). She fits that pattern.
A rough calculation shows the size of the change. If her creatinine clearance was about 40 mL/min when gabapentin was started and is about 20 mL/min now, and clearance follows creatinine clearance in a straight line, her gabapentin clearance has roughly halved. Average steady-state concentration equals the dosing rate divided by clearance, so the unchanged dose now produces about twice the exposure. Nothing about the prescription changed; the patient did, and the prescription was never revisited to follow her.
The Regimen Change, and the One Not Chosen
The change the reasoning supports is a dose reduction, not a switch. The manufacturer's labeling for gabapentin recommends 200 to 700 mg a day for a creatinine clearance of 15 to 29 mL/min, given in one or two doses, and the American Geriatrics Society Beers Criteria advise reducing gabapentin dose when kidney function is reduced (American Geriatrics Society Beers Criteria Update Expert Panel, 2023). I would reduce her to 300 mg at bedtime. That brings her into the recommended range, cuts her daily exposure by about two thirds, and places the peak at night, when drowsiness matters least. Because her pain is well controlled, I would accept the risk of some breakthrough pain and reassess rather than start low and risk losing control entirely.
The alternative change that would have been reasonable is stopping gabapentin and substituting a 5% lidocaine patch over the affected dermatome, which is used in postherpetic neuralgia and has little systemic absorption. It was not chosen as the first step because her pain has responded well to gabapentin, and replacing a working drug with one whose effect in her is unknown adds a second uncertainty to the first. Pregabalin, another option, was set aside for the same pharmacokinetic reason as gabapentin: it is also cleared by the kidneys and would need the same adjustment. The lidocaine patch remains the next step if pain returns at the lower dose.
Using creatinine clearance rather than eGFR for this decision is deliberate. The labeled dose ranges were developed using creatinine clearance, and for a small, older woman the two estimates can differ enough to change the dosing band. The KDIGO guideline supports using the estimate of kidney function best suited to the drug decision at hand (Stevens et al., 2024).
What Will Be Watched, and When
Drowsiness and dizziness should improve within about a week, the time needed for her new, lower steady state to settle at her prolonged half-life. Her daughter will call at day 5 to report afternoon alertness, orthostatic symptoms, and any falls. Pain will be scored daily by the patient on a 0 to 10 scale, with a visit at 2 weeks. If pain rises above 5 for most days, the lidocaine patch is added before any increase in gabapentin. Kidney function will be rechecked in 3 months, and sooner with any acute illness, because a further fall in clearance would again raise her exposure without any change in dose. Her medication list will carry a note that the gabapentin dose is tied to her creatinine clearance and must be reviewed whenever kidney function changes.
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
Blum, R. A., Comstock, T. J., Sica, D. A., Schultz, R. W., Keller, E., Reetze, P., Bockbrader, H., Tuerck, D., Busch, J. A., Reece, P. A., & Sedman, A. J. (1994). Pharmacokinetics of gabapentin in subjects with various degrees of renal function. Clinical Pharmacology and Therapeutics, 56(2), 154-159. https://doi.org/10.1038/clpt.1994.118
Cockcroft, D. W., & Gault, M. H. (1976). Prediction of creatinine clearance from serum creatinine. Nephron, 16(1), 31-41. https://doi.org/10.1159/000180580
Inker, L. A., Eneanya, N. D., Coresh, J., Tighiouart, H., Wang, D., Sang, Y., Crews, D. C., Doria, A., Estrella, M. M., Froissart, M., Grams, M. E., Greene, T., Grubb, A., Gudnason, V., Gutiérrez, O. M., Kalil, R., Karger, A. B., Mauer, M., Navis, G., . . . Levey, A. S. (2021). New creatinine- and cystatin C-based equations to estimate GFR without race. The New England Journal of Medicine, 385(19), 1737-1749. https://doi.org/10.1056/NEJMoa2102953
Stevens, P. E., Ahmed, S. B., Carrero, J. J., Foster, B., Francis, A., Hall, R. K., Herrington, W. G., Hill, G., Inker, L. A., Kazancıoğlu, R., Lamb, E., Lin, P., Madero, M., McIntyre, N., Morrow, K., Roberts, G., Sabanayagam, D., Schaeffner, E., Shlipak, M., . . . Levin, A. (2024). KDIGO 2024 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney International, 105(4S), S117-S314. https://doi.org/10.1016/j.kint.2023.10.018
Zand, L., McKian, K. P., & Qian, Q. (2010). Gabapentin toxicity in patients with chronic kidney disease: A preventable cause of morbidity. The American Journal of Medicine, 123(4), 367-373. https://doi.org/10.1016/j.amjmed.2009.09.030
Reading the DNRS 6521 Week 2 instructions
The second week often asks for a written case in which a patient factor requires a dosing change. Kidney impairment is common, though some sections use hepatic disease or age. You present the patient with relevant laboratory values, explain the pharmacokinetic consequence, propose a specific regimen change with a reason, and describe monitoring. Prompts often expect the estimation method for kidney function to be named and justified. A brief APA 7 paper of three to five pages with title page and references is typical, citing labeling, guidelines or primary pharmacokinetic studies. The case may be composite but should be realistic enough that the numbers can be checked. Expect to explain why the alternative you rejected was less suitable. Some instructors also want a sentence on what the patient will be told.
How the DNRS 6521 Week 2 example is put together
Three pages under four headings, opening with the composite patient in eight lines. Organ function appears there as a stated degree rather than as a label, because the argument later needs a quantity of impairment to reason about. The second heading works out what falls, what accumulates and over what span, staying with mechanism rather than reaching immediately for an adjustment. The third heading states the regimen change the reasoning supports and, more importantly, states the alternative change that would have been reasonable and why it was not chosen. A fourth heading gives what would be watched afterward and at what interval. Six references, weighted toward primary pharmacokinetic work rather than tertiary summaries, sit under the claims that could be contested.
Reading the DNRS 6521 Week 2 rubric
The scored quality is proportional reasoning. A paper stating that impairment requires caution has said something no rubric can reward, because caution is not a quantity and cannot be checked. Credit lands on sentences connecting a degree of reduced function to a specific consequence for accumulation or interval. Graders also weigh whether the rejected alternative was genuinely defensible, as a token alternative makes the whole comparison decorative. Documentation of reasoning is often its own criterion in doctoral pharmacology, meaning the paper must show why rather than only what. Papers spending a page restating the case usually reach the monitoring heading with two sentences left, and monitoring is where the last available band sits. Source tier is checked, and it is checked more strictly than source count.
DNRS 6521 Week 2 help: mistakes that cost marks
Write-ups lose marks fastest when they say the dose should be reduced "with caution" and stop there. Give a number and show where it came from. Writers also go wrong by quoting an eGFR when the labeling dose bands rely on creatinine clearance; say which you used and why. Students also forget that accumulation takes several half-lives to appear, so the timing of adverse effects goes unexplained. Avoid listing every possible adverse effect when the case calls for the ones tied to accumulation, such as sedation and unsteadiness. Keep the weight, age and creatinine identical throughout so the calculation can be reproduced. Name the alternative you rejected and the reason. Finally, make the monitoring plan specific in what is checked and when.
Get a DNRS 6521 Week 2 example written to your instructions
Forward the case the classroom supplied, the page limit and the rubric, and a write-up that reasons from a stated degree of impairment comes back to you. The first custom one is free and lands inside 24 to 48 hours. Records belonging to somebody you have actually treated are theirs and are never worked into an example here.
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DNRS 6521 Week 2 questions, answered
Does the write-up need laboratory values?
It needs something quantitative to reason from, and a stated degree of impairment does that job whether it arrives as a value or as a described level of function. The example uses one figure and returns to it repeatedly. Where the classroom case supplies its own numbers, those govern, and the proportional argument is written onto them instead.
Is naming the agent required for this assignment?
Your prompt decides, and many doctoral cases do name one or ask the writer to select. The example is written from handling properties so that the argument holds either way. When an agent is assigned, the custom version carries it through every heading, and the structure shown here does not change to accommodate it.
How is the composite patient constructed?
From published case patterns and textbook physiology, assembled so the impairment is severe enough to matter and mild enough to leave a real choice. No encounter of yours is used as raw material for that, and nothing you send about your own workplace is written into the returned document either.
Where can I find a free DNRS 6521 Week 2 sample paper?
The gabapentin case write-up is shown in full here, including the kidney function estimate, the regimen change, the option not chosen and the monitoring section.
How is gabapentin adjusted for kidney function in DNRS 6521 Week 2?
The example estimates creatinine clearance with Cockcroft and Gault, then lowers the total daily dose to the band the labeling gives for that clearance, with checks for sedation and falls.