Kinetic GFR rather than a single creatinine drives this MN650 renal dosing worksheet, which adjusts five agents for a composite adult whose kidney injury is still worsening and may need CRRT. Searches like "mn 650 unit 7 assignment example", "mn650 unit 7 sample" and "mn650 unit 7 example" land here.
Renal Dosing Worksheet for Septic Acute Kidney Injury: Five Drugs Dosed for Where Clearance Is Heading
[Student Name]
Purdue University Global
MN650: Specialized Pharmacology for the AGACNP Acute Care NP
Unit 7 Assignment
[Instructor Name]
[Date]
Composite patient written as a model document. Doses are bracketed placeholders; nothing here is a prescribing instruction.
Worked Arithmetic
The patient: a composite 57-year-old man, 80 kg, with septic shock from a biliary source. Creatinine 1.1 mg/dL on admission, 1.9 at 24 hours and 2.8 at 48 hours. Urine output falling.
Why a steady-state equation misleads. The Cockcroft-Gault equation assumes creatinine is stable (Cockcroft & Gault, 1976). Applied to today's 2.8, it gives (140 − 57) × 80 / (72 × 2.8), a clearance of about 33 mL/min. But creatinine is still rising by about 0.9 mg/dL a day, which means the kidneys are clearing far less than that value implies, because creatinine has not yet caught up with the loss of function. A steady-state equation applied to a rising creatinine overstates function and leads to accumulation.
Kinetic GFR. Chen's method estimates filtration while creatinine is changing (Chen, 2013). It multiplies a baseline clearance by the ratio of baseline to mean creatinine, then reduces the result by how fast creatinine is rising compared with the fastest rise expected when filtration stops altogether.
Baseline clearance at creatinine 1.1, by the same equation: (140 − 57) × 80 / (72 × 1.1), about 84 mL/min.
Mean creatinine over the last 24 hours: (1.9 + 2.8) / 2 = 2.35.
Rise over 24 hours: 0.9 mg/dL; assumed maximum daily rise with no filtration: 1.5 mg/dL.
Kinetic GFR = (1.1 × 84 / 2.35) × (1 − 0.9 / 1.5) = 39.3 × 0.4 = about 16 mL/min.
Working estimate: 15 to 20 mL/min, and falling.
If CRRT starts. KDIGO's acute kidney injury guideline recommends an effluent dose of 20 to 25 mL/kg/h for continuous renal replacement therapy (Kidney Disease: Improving Global Outcomes Acute Kidney Injury Work Group, 2012). At 25 mL/kg/h for 80 kg, effluent is 2,000 mL/h, about 33 mL/min. Drug clearance by CRRT is roughly that rate multiplied by the fraction of the drug not bound to protein, so for a lightly bound drug, CRRT adds a clearance of about 25 to 33 mL/min.
Dosing Table
1. Meropenem. Route: renal. Standard: [1 g every 8 hours]. At current estimate: full first dose; next dose reduced to [a composite interval] only if creatinine continues to rise. If CRRT starts: [a composite CRRT dose]. Recheck trigger: creatinine at 12 hours; CRRT start. Reason: underexposure in sepsis costs more than a brief excess, so the first dose is not cut.
2. Levetiracetam. Route: renal, mostly unchanged. Standard: [composite]. At current estimate: reduced now to [a composite dose for clearance below 30]. If CRRT starts: [composite, with a supplemental dose]. Recheck trigger: creatinine daily. Reason: accumulation causes sedation that would muddy neurologic checks.
3. Famotidine. Route: renal. Standard: [composite]. At current estimate: reduce to [composite] or stop if no indication. If CRRT starts: [composite]. Recheck trigger: daily review of need. Reason: accumulation in kidney failure can cause confusion.
4. Ceftriaxone. Route: biliary and renal. Standard: [composite]. At current estimate: no renal adjustment. If CRRT starts: no adjustment. Recheck trigger: none renal. Reason: dual elimination means kidney failure alone does not require a change.
5. Linezolid. Route: nonrenal metabolism. Standard: [composite]. At current estimate: no renal adjustment. If CRRT starts: no adjustment. Recheck trigger: platelets twice weekly. Reason: kidney failure does not change its dose, but its metabolites accumulate and platelets should be watched.
Why the Two Unchanged Rows Appear
Ceftriaxone and linezolid carry no renal adjustment, and the worksheet says so explicitly. Listing them shows that each drug was checked rather than skipped.
When the Sheet Is Redone
At 12 hours with the next creatinine, at the start of CRRT, and whenever creatinine changes by more than 0.5 mg/dL in a day, in either direction. If kidney function recovers, the kinetic estimate will rise and doses reduced for accumulation must be raised again.
References
Chen, S. (2013). Retooling the creatinine clearance equation to estimate kinetic GFR when the plasma creatinine is changing acutely. Journal of the American Society of Nephrology, 24(6), 877-888. https://doi.org/10.1681/ASN.2012070653
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
Kidney Disease: Improving Global Outcomes Acute Kidney Injury Work Group. (2012). KDIGO clinical practice guideline for acute kidney injury. Kidney International Supplements, 2(1), 1-138.
How this MN650 Unit 7 example is structured
Clearance is treated as a moving number with a direction. The arithmetic page comes first because every row depends on the estimate, and the estimate is argued rather than asserted: a steady-state equation applied to a rising creatinine would overstate function and lead to accumulation, while dosing to the worst imaginable value would underdose a septic patient in whom early antibiotic exposure matters most. The table resolves that tension row by row. Meropenem keeps a full first dose and is reduced at the next interval only if the trend continues, since underexposure in sepsis costs more than a brief excess. Levetiracetam is reduced sooner, because accumulation causes sedation that muddies neurologic checks. Famotidine is adjusted or stopped. The two unaffected agents appear so a marker can see that each drug was actually checked. A final line names when the sheet is redone.
Get an MN650 Unit 7 example written to your instructions
Your MN650 Unit 7 worksheet may list different drugs or a different trend; send the case, the medication list and the rubric as they stand. At no charge for a first request, and typically inside 24-48h, the sample treats clearance as moving, shows the estimate and its assumptions, and justifies every row, the unchanged ones included. 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.
MN650 Unit 7 questions, answered
Is a steady-state equation ever acceptable here?
It can appear, with its limitation stated. Many drug labels base renal adjustments on the equation their original studies used, so it still matters for matching a label. The sample explains that such equations assume a stable creatinine, shows where that assumption fails in this case, and sets a kinetic estimate beside it.
What if the patient is already on dialysis?
The worksheet changes shape. Intermittent hemodialysis, continuous therapy and peritoneal dialysis clear drugs differently, and timing matters: a dose given just before a session may be largely removed. The sample would name the modality, the schedule and the drugs the circuit removes, and bracket doses for each, citing the drug information reference used.
Can the worksheet's adjusted doses be used clinically?
No. They illustrate how adjustment reasoning is displayed in a coursework table, which is what is graded. Renal dosing for a real patient depends on current labels, institutional references, pharmacist review and the treating team. Each figure sits inside brackets, and the worksheet names a source for every one so the reasoning can be traced.