NBHS1314 Pharmacology for Nurses Assignment Sample: Digoxin, Warfarin and Furosemide Case (Part I)

For information and reference only – not to be submitted as your own work.

This extract shows how a Part I essay for NBHS1314 Pharmacology for Nurses (September Semester 2026) can be structured. The task centres on a 68-year-old man with chronic heart failure and atrial fibrillation who is taking digoxin, furosemide and warfarin, and who also uses over-the-counter ibuprofen and ginkgo biloba without telling his care team. The extract covers the introduction, the drug-by-drug analysis, and the comparison of digoxin toxicity with anticoagulant-related bleeding. Nursing management, education and the conclusion are outlined briefly, and the full essay would develop them to the stated word count. The case is fictional, and the figures quoted are those given in the brief.

Introduction and case context

A 68-year-old man with chronic heart failure and atrial fibrillation presents with nausea, poor appetite, weakness, blurred yellow vision, gum bleeding and multiple bruises. His pulse is 48 beats per minute and irregular. Serum potassium is 2.9 mmol/L, serum digoxin is 2.6 ng/mL and the INR is 4.8. He takes digoxin 0.125 mg once daily, furosemide 40 mg twice daily and warfarin 3 mg once daily, and has been self-medicating with ibuprofen for knee pain and ginkgo biloba.

This essay argues that his presentation is best explained as two linked adverse events rather than two separate ones. Furosemide-induced hypokalaemia, probably worsened by reduced renal function and poor intake, has made digoxin toxic. At the same time, three agents with different mechanisms (warfarin, ibuprofen and ginkgo biloba) have combined to raise bleeding risk. Drug effects are described first, the immediate risks are then compared and prioritised, and the nursing response is justified with reference to current guidelines (McDonagh et al., 2021; Patel & Wright, 2023).

Critical analysis of actions, adverse effects and interactions

Digoxin

Digoxin inhibits the sodium–potassium ATPase pump. In the heart this raises intracellular calcium and increases contractility, and it also increases vagal tone and slows conduction through the atrioventricular (AV) node, which is why it is used for rate control in atrial fibrillation (Gheorghiade et al., 2004). Its narrow therapeutic index is the central problem here. The commonly cited laboratory range is roughly 0.5–2.0 ng/mL, and in heart failure the lower end of that range, often about 0.5–0.9 ng/mL, is generally preferred (Ehle et al., 2011). Local laboratory ranges differ, so the report should be read against the ward’s own reference interval. A level of 2.6 ng/mL is above the usual range, and the symptoms support toxicity: nausea, anorexia, weakness, disturbed colour vision and a slow, irregular pulse are all recognised features (Patel & Wright, 2023). Samples are usually interpreted when taken at least six hours after the last dose, so the timing of the sample matters when the result is interpreted (Patel & Wright, 2023).

Digoxin is largely cleared by the kidneys. Any fall in renal function, whether from heart failure, dehydration or an NSAID, will therefore push the serum level up even if the dose has not changed. Older age is a further risk factor (Patel & Wright, 2023).

Furosemide and the potassium link

Furosemide is a loop diuretic that reduces congestion by blocking sodium and chloride reabsorption in the thick ascending limb, but it also increases urinary loss of potassium and magnesium. Hypokalaemia matters because potassium and digoxin compete for the same binding site on the sodium–potassium pump. When extracellular potassium is low, digoxin binds more readily, and toxicity can appear at serum concentrations that would otherwise be tolerated (Gheorghiade et al., 2004; Patel & Wright, 2023). A potassium of 2.9 mmol/L is also arrhythmogenic in its own right, so in this patient the low potassium and the raised digoxin level reinforce each other. Vomiting or poor oral intake, as reported here, would worsen potassium and fluid losses further.

Warfarin

Warfarin inhibits the vitamin K-dependent clotting factors and is used in atrial fibrillation to reduce stroke risk. An INR of 4.8 is well above the usual therapeutic target of 2.0–3.0 for this indication. Warfarin has a long list of drug, herbal and dietary interactions, and its effect also rises when oral intake falls, when the liver is congested, or during acute illness (Holbrook et al., 2005). In this case, reduced eating and possible hepatic congestion from heart failure are plausible contributors to the INR rise, and gum bleeding and bruising show that the anticoagulant effect is clinically active.

Ibuprofen

Ibuprofen contributes to the picture in three ways. First, it inhibits platelet function and irritates the gastric mucosa, which increases the risk of gastrointestinal bleeding, and this risk is additive to that of warfarin (Coxib and traditional NSAID Trialists’ Collaboration, 2013; Holbrook et al., 2005). Second, by inhibiting renal prostaglandins it can reduce renal perfusion and cause sodium and fluid retention. This blunts the effect of furosemide and can precipitate worsening heart failure, which is why NSAIDs are not recommended in heart failure (McDonagh et al., 2021). Third, any resulting fall in renal clearance would raise digoxin levels. The patient’s decision to treat knee pain with an NSAID is therefore a medication-safety issue as well as a pain-management one, and the AGS Beers Criteria also flag the combination of NSAIDs with anticoagulants in older adults (2023 American Geriatrics Society Beers Criteria Update Expert Panel, 2023).

Ginkgo biloba

Ginkgo biloba extracts have antiplatelet activity in laboratory studies, and case reports link ginkgo with bleeding. However, controlled evidence of a clinically significant interaction with warfarin is mixed, so the claim should be made with care (Bone, 2008). The point for nursing practice is that a herbal product with possible antiplatelet effects should be treated as a potential contributor to bleeding when it is taken with an anticoagulant and an NSAID. Because the patient did not disclose it, it also shows a gap in medicines reconciliation.

Combined bleeding risk and the overall pathway

The combined pathway can be summarised as follows. Furosemide lowers potassium, ibuprofen may reduce renal clearance, and both increase digoxin toxicity. Warfarin has a raised INR, and ibuprofen and ginkgo biloba add platelet-related bleeding risk on top of it. Either problem alone would justify review, but together they make the patient unstable in two directions at once.

Comparison and prioritisation of immediate risks

Both risks are urgent, but with the information given the immediate priority is the cardiac one. A slow irregular rhythm in a patient with hypokalaemia and a high digoxin level can deteriorate without warning, whereas the bleeding so far is mucosal and cutaneous with no stated haemodynamic compromise. That ranking would change at once if the patient showed signs of a major bleed, such as black stools, haematemesis, a falling blood pressure or new neurological symptoms. A sound answer therefore states the priority and the conditions under which it reverses, rather than treating the order as fixed. Both problems are managed together in practice, because the same nurse is monitoring the heart rhythm and the bleeding.

For more worked examples in this field, see our nursing assignment help page, or read the companion guide to this brief for a marking-focused approach.

Nursing management, monitoring, education and medication safety (outline)

Immediate actions. Assess airway, breathing and circulation, start continuous ECG monitoring, record full observations, and escalate urgently to the medical team. Withhold digoxin, warfarin, ibuprofen and ginkgo biloba until the prescriber has reviewed them, and have the digoxin-specific antibody fragments and vitamin K available in line with the local protocol, as the prescriber directs. Potassium and magnesium replacement is a prescriber-led treatment under cardiac monitoring (Patel & Wright, 2023).

Monitoring. Heart rate and rhythm, blood pressure, urine output and fluid balance, repeat urea and electrolytes, magnesium, creatinine, full blood count and INR, and a structured bleeding check that includes stools, urine, gums, skin and neurological status. Apply falls and bleeding precautions, avoid intramuscular injections, and use a soft toothbrush.

Education and medication safety. Use teach-back to explain why NSAIDs and herbal products must be disclosed, how to recognise warning symptoms (visual change, nausea, slow or irregular pulse, bleeding), and why regular INR and potassium checks matter. Agree a safer pain plan with the prescriber or pharmacist, carry an up-to-date medicines list, and ask pharmacists to run a structured medicines review. A respectful, non-judgemental approach also matters, because many patients do not regard traditional or over-the-counter products as medicines.

The conclusion should return to the central argument: the toxicity and the bleeding were both predictable and partly preventable through monitoring, reconciliation and patient education.

Need a similar model answer for your own brief? Our case study help service is built around your exact marking criteria.

About the expert

This extract was reviewed against the subject area by Aisyah Nadia, whose profile lists a nursing degree from Monash University and experience as a registered nurse, with subject strengths in mental health, aged care and community health.

Have your own NBHS1314 question? Browse recently solved questions or submit your brief for a quote.

References

2023 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

Bone, K. M. (2008). Potential interaction of Ginkgo biloba leaf with antiplatelet or anticoagulant drugs: What is the evidence? Molecular Nutrition & Food Research, 52(7), 764–771. https://doi.org/10.1002/mnfr.200700098

Coxib and traditional NSAID Trialists’ (CNT) Collaboration. (2013). Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: Meta-analyses of individual participant data from randomised trials. The Lancet, 382(9894), 769–779. https://doi.org/10.1016/S0140-6736(13)60900-9

Ehle, M., Patel, C., & Giugliano, R. P. (2011). Digoxin: Clinical highlights: A review of digoxin and its use in contemporary medicine. Critical Pathways in Cardiology, 10(2), 93–98. https://doi.org/10.1097/HPC.0b013e318221e7dd

Gheorghiade, M., Adams, K. F., Jr., & Colucci, W. S. (2004). Digoxin in the management of cardiovascular disorders. Circulation, 109(24), 2959–2964. https://doi.org/10.1161/01.CIR.0000132482.95686.87

Holbrook, A. M., Pereira, J. A., Labiris, R., McDonald, H., Douketis, J. D., Crowther, M., & Wells, P. S. (2005). Systematic overview of warfarin and its drug and food interactions. Archives of Internal Medicine, 165(10), 1095–1106. https://doi.org/10.1001/archinte.165.10.1095

McDonagh, T. A., Metra, M., Adamo, M., Gardner, R. S., Baumbach, A., Böhm, M., Burri, H., Butler, J., Čelutkienė, J., Chioncel, O., Cleland, J. G. F., Coats, A. J. S., Crespo-Leiro, M. G., Farmakis, D., Gilard, M., Heymans, S., Hoes, A. W., Jaarsma, T., Jankowska, E. A., … Waltenberger, J. (2021). 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. European Heart Journal, 42(36), 3599–3726. https://doi.org/10.1093/eurheartj/ehab368

Patel, K., & Wright, P. (2023). Digoxin monitoring and toxicity management. The Pharmaceutical Journal, 310(7969). https://doi.org/10.1211/PJ.2022.1.170827