# A client stabilized on theophylline stops smoking after 20 years. Which level adjustment should the nurse anticipate, and why?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=391783&lang=en  
> language: en  
> subject: Medical Emergencies  
> category: PA

## Question

A client stabilized on theophylline stops smoking after 20 years. Which level adjustment should the nurse anticipate, and why?

## Option

1. Theophylline should be doubled to compensate for nicotine withdrawal
2. Level may rise toward toxicity; dose typically needs reduction because smoking induces CYP1A2 and quitting reverses this induction **✔ Correct answer**
3. Level should fall because nicotine accelerates theophylline elimination
4. No change is expected because smoking does not affect theophylline metabolism

**Correct answer: 2**

## Explanation

Correct (2): Cigarette smoke induces CYP1A2, accelerating theophylline metabolism. Smokers typically need higher doses; when smoking stops, induction reverses over 1-4 weeks → levels rise with risk of toxicity. Dose reduction is typically required. (1,3,4) Wrong direction/mechanism.

## In-depth explanation

Memory Tip Smoking = "Sm-OKE = Sp-OKE up the engine (CYP1A2)." Drugs metabolized by CYP1A2 (theophylline, caffeine, olanzapine, clozapine) accumulate after quitting.

## Clinical scenario

Scenario 58-year-old male on stable theophylline 300 mg BID × 5 years, smoked 1 pack/day × 20 years. Quit smoking 4 weeks ago. Current routine theophylline level pending.

## Key concepts

- **CYP1A2 induction** — Cigarette smoke increases CYP1A2 activity, lowering levels of theophylline, caffeine, olanzapine, clozapine.
- **Smoking cessation pharmacokinetics** — CYP1A2 returns to baseline over 1-4 weeks; substrate drug levels rise.
- **Theophylline dose adjustment** — Reduce dose after smoking cessation; check level at 1-2 weeks.

## Related questions

- [A nurse is caring for an alert adult client with type 1 diabetes who reports tremors, swea…](https://mymerci.kr/pages/nclex_q.php?qn_id=360524&lang=en)
- [A 68-year-old client with COPD is admitted with shortness of breath and SpO2 86% on room a…](https://mymerci.kr/pages/nclex_q.php?qn_id=362940&lang=en)
- [A 58-year-old client arrives at the emergency department with crushing substernal chest pa…](https://mymerci.kr/pages/nclex_q.php?qn_id=362976&lang=en)
- [A 72-year-old client is brought to the emergency department by family who report that the …](https://mymerci.kr/pages/nclex_q.php?qn_id=363003&lang=en)
- [A 79-year-old client is admitted from a long-term care facility with diarrhea, decreased o…](https://mymerci.kr/pages/nclex_q.php?qn_id=363089&lang=en)
- [A 76-year-old female with chronic heart failure and atrial fibrillation receives digoxin 0…](https://mymerci.kr/pages/nclex_q.php?qn_id=374883&lang=en)
- [A 70-year-old client on long-term digoxin therapy reports new yellow-green halos around li…](https://mymerci.kr/pages/nclex_q.php?qn_id=374884&lang=en)
- [A 58-year-old client with type 2 diabetes mellitus and migraine prophylaxis is taking prop…](https://mymerci.kr/pages/nclex_q.php?qn_id=374893&lang=en)

## Read in another language

- [en](https://mymerci.kr/pages/nclex_q.php?qn_id=391783&lang=en)
- [ko](https://mymerci.kr/pages/nclex_q.php?qn_id=391783&lang=ko)
- [ja](https://mymerci.kr/pages/nclex_q.php?qn_id=391783&lang=ja)
- [zh-TW](https://mymerci.kr/pages/nclex_q.php?qn_id=391783&lang=zh-tw)
- [vi](https://mymerci.kr/pages/nclex_q.php?qn_id=391783&lang=vi)

---

More free questions: [NCLEX-RN Practice](https://mymerci.kr/pages/nclex_bank.php?lang=en)

_For study reference only. Always follow current clinical guidelines and your institution’s protocols._