Report serum level over 20 mcg/mL or any seizures and dysrhythmias immediately.
Before you read
Test yourself first: 5 questions
Question 1 of 5
A client taking theophylline reports nausea, vomiting, and palpitations. The nurse suspects theophylline toxicity. Which additional sign supports this concern?
Answer: A. Theophylline toxicity causes central nervous system and cardiac stimulation, producing tachycardia, restlessness, and in severe cases seizures. Bradycardia and sedation are not features of theophylline toxicity, and constipation is unrelated. The nurse should hold the drug and notify the provider.
Question 2 of 5
A nurse is teaching a client who smokes and takes theophylline for COPD. Why is this combination clinically significant?
Answer: A. Cigarette smoke induces hepatic enzymes that increase theophylline metabolism, lowering serum levels and reducing effectiveness; smokers often require higher doses. If the client stops smoking, theophylline clearance decreases and levels can rise into the toxic range. The nurse must teach that any change in smoking status requires dose reassessment and level monitoring.
Question 3 of 5
A client receiving aminophylline has a theophylline level of 25 mcg/mL. Which action should the nurse take?
Answer: A. The therapeutic theophylline range is 10-20 mcg/mL. A level of 25 indicates toxicity, which causes tachycardia, seizures, and dysrhythmias. The nurse should hold the medication and notify the provider.
Question 4 of 5
A client receiving intravenous theophylline reports nausea, palpitations, and feeling jittery. The nurse notes a heart rate of 124 beats per minute. Which is the nurse's priority action?
Answer: A. These findings suggest theophylline toxicity. The priority is to stop or hold the infusion and notify the provider, then obtain a stat serum theophylline level. Toxicity can progress to seizures and life-threatening dysrhythmias. Continuing the infusion or simply reassuring the client would allow toxicity to worsen.
Question 5 of 5
A client takes theophylline for a respiratory condition. The therapeutic level is narrow; the nurse watches for toxicity signs such as:
Answer: B. Theophylline toxicity (level > 20 mcg/mL): nausea/vomiting, tachycardia/palpitations, restlessness, tremor, and seizures. Teach to avoid excess caffeine and report these symptoms.
Keep the streak going with more questions like these, each with a full rationale.
What is theophylline?
It has a very narrow therapeutic range, so serum levels must be monitored closely. Memory aid: keep the level THEO-rapeutic at 10-20 mcg/mL.
Key points to remember
- Narrow therapeutic serum level is 10-20 mcg/mL; toxicity rises sharply above this.
- Caffeine, smoking, and many drugs alter levels; smoking increases metabolism and lowers blood levels.
- Early toxicity signs include nausea, vomiting, restlessness, insomnia, and tachycardia.
- Severe toxicity causes seizures and life-threatening dysrhythmias.
- Avoid caffeine-containing foods/beverages because they add to CNS and cardiac stimulation.
Nursing priorities
- Monitor serum theophylline levels and report values outside 10-20 mcg/mL.
- Assess heart rate and rhythm for tachycardia and dysrhythmias.
- Hold the dose and notify the provider for nausea, vomiting, restlessness, or palpitations.
- Review medication and smoking history for interactions that change drug levels.
Labs & values
Patient teaching
- Take doses at the same time each day and do not chew or crush sustained-release tablets.
- Limit caffeine (coffee, tea, cola, energy drinks, chocolate).
- Tell your provider if you start or stop smoking, as it changes your dose needs.
- Report nausea, vomiting, fast heartbeat, restlessness, or trouble sleeping.
Red flags: report now
- Report serum level over 20 mcg/mL or any seizures and dysrhythmias immediately.
- Never ignore early GI or CNS stimulation symptoms, as they can precede severe toxicity.
References
Clinical references for this topic
