Digoxin toxicity with bradycardia or arrhythmia is an emergency; hold the drug and report it.
Before you read
Test yourself first: 5 questions
Question 1 of 5
A client taking warfarin has an INR of 1.2 while the prescribed therapeutic range is 2.0 to 3.0. How should the nurse interpret this result?
Answer: C. An INR of 1.2 is below the therapeutic range of 2.0 to 3.0, meaning the client is not adequately anticoagulated and remains at risk for clot formation. A subtherapeutic INR does not indicate bleeding risk; that concern arises when the INR is above range. The dose will likely need to be increased, not held.
Question 2 of 5
A client taking warfarin has an INR of 5.2 and reports gum bleeding. What is the nurse's priority concern?
Answer: A. An INR of 5.2 is well above the therapeutic range (2.0 to 3.0) and the gum bleeding signals over-anticoagulation with active bleeding risk; the priority is the risk of hemorrhage and the need to hold the dose and notify the provider. The value is not therapeutic, subtherapeutic, or a sign of clot formation.
Question 3 of 5
A client recovering from surgery refuses opioid pain medication, stating a fear of becoming addicted. What is the nurse's most therapeutic response?
Answer: A. Therapeutic communication addresses the concern with accurate information: when opioids are used appropriately for acute pain under medical supervision, the risk of addiction is low, and untreated pain impairs recovery. Dismissing, shaming, or simply documenting the refusal without education are not therapeutic.
Question 4 of 5
A client taking a theophylline (xanthine bronchodilator) preparation has a serum theophylline level drawn. Which result is within the therapeutic range?
Answer: B. The therapeutic range for serum theophylline is 10 to 20 mcg/mL. A level of 15 mcg/mL is therapeutic. Levels above 20 mcg/mL increase the risk of toxicity, which manifests as nausea, vomiting, tachycardia, seizures, and dysrhythmias. Levels below 10 mcg/mL are subtherapeutic.
Question 5 of 5
A client is to begin warfarin while still receiving a therapeutic heparin infusion. Which statement best explains why both anticoagulants are given together initially?
Answer: A. Warfarin takes several days to achieve a therapeutic effect because circulating clotting factors must be depleted, so heparin provides immediate anticoagulation during this bridging period. The overlap is intentional, not a medication error, and continues until the INR reaches the therapeutic range.
Keep the streak going with more questions like these, each with a full rationale.
What is therapeutic drug levels?
A trough is drawn just before the next dose to check the lowest level, and a peak is drawn after absorption to check the highest level. Drugs like digoxin, lithium, vancomycin, and phenytoin require close monitoring.
Key points to remember
- A narrow therapeutic index means small changes in level can move from effective to toxic.
- Trough levels are drawn immediately before the next scheduled dose.
- Therapeutic digoxin is 0.5 to 2.0 ng/mL, and toxicity causes nausea, visual changes, and arrhythmias.
- Therapeutic lithium is 0.6 to 1.2 mEq/L, and levels above 1.5 are toxic.
- Vancomycin troughs guide dosing and protect against kidney and ear toxicity.
- Therapeutic phenytoin is 10 to 20 mcg/mL, and toxicity causes nystagmus and ataxia.
Nursing priorities
- Draw trough and peak levels at the correct times relative to the dose.
- Verify the level is therapeutic before administering the next dose of a narrow-index drug.
- Assess for signs of toxicity specific to the medication being monitored.
- Hold the dose and notify the provider when a level is in the toxic range.
- Monitor renal function for drugs cleared by the kidneys, such as digoxin and vancomycin.
Labs & values
Patient teaching
- Take the medication exactly as prescribed and keep all scheduled lab draws.
- Maintain consistent fluid and salt intake with lithium, and report tremor, vomiting, or confusion.
Red flags: report now
- Digoxin toxicity with bradycardia or arrhythmia is an emergency; hold the drug and report it.
- Lithium toxicity with confusion, tremor, or seizures requires holding the dose and urgent notification.
- Never give the next dose of a monitored drug if the level is above the therapeutic range.
References
Clinical references for this topic
