A client stabilized on theophylline stops smoking after 20 y… | MyMerci
Medical EmergenciesPA
Question
A client stabilized on theophylline stops smoking after 20 years. Which level adjustment should the nurse anticipate, and why?
1Theophylline should be doubled to compensate for nicotine withdrawal
2Level may rise toward toxicity; dose typically needs reduction because smoking induces CYP1A2 and quitting reverses this induction✓ Correct answer
3Level should fall because nicotine accelerates theophylline elimination
4No change is expected because smoking does not affect theophylline metabolism
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.