# A 60-year-old client on stable levothyroxine 100 mcg every morning is newly prescribed ferrous sulfate 325 mg twice daily for iron deficiency anemia. Which nursing instruction best preserves thyroid hormone absorption?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=375094&lang=en  
> language: en  
> subject: Medical Emergencies  
> category: PA

## Question

A 60-year-old client on stable levothyroxine 100 mcg every morning is newly prescribed ferrous sulfate 325 mg twice daily for iron deficiency anemia. Which nursing instruction best preserves thyroid hormone absorption?

## Option

1. Take levothyroxine with your morning meal and then take ferrous sulfate later with lunch to separate them.
2. Take levothyroxine and ferrous sulfate together with breakfast to simplify the morning routine and improve compliance.
3. Take levothyroxine on waking with water; take ferrous sulfate at least 4 hours later, such as with lunch and dinner. **✔ Correct answer**
4. Discontinue levothyroxine while taking iron, and restart it after the anemia is corrected in a month.

**Correct answer: 3**

## Explanation

Iron, calcium, magnesium, antacids, sucralfate, bile-acid binders such as cholestyramine, and proton pump inhibitors all reduce levothyroxine absorption either by chelation or by altering gastric pH. The standard intervention is temporal separation of at least 4 hours, while keeping levothyroxine on its routine empty-stomach morning schedule. Stopping the thyroid hormone risks profound hypothyroidism and is not appropriate for treating iron deficiency. Crushing levothyroxine is acceptable for swallowing difficulty but mixing it with iron defeats the separation strategy. After a new interacting medication is started, recheck TSH in 6 weeks because absorption changes can shift TSH out of range and require dose adjustment.

## In-depth explanation

The 4-hour separation rule is the universal answer when an absorption-interfering drug is added to stable levothyroxine therapy. Always reassess TSH after the change.

## 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=375094&lang=en)
- [ko](https://mymerci.kr/pages/nclex_q.php?qn_id=375094&lang=ko)
- [ja](https://mymerci.kr/pages/nclex_q.php?qn_id=375094&lang=ja)
- [zh-TW](https://mymerci.kr/pages/nclex_q.php?qn_id=375094&lang=zh-tw)
- [vi](https://mymerci.kr/pages/nclex_q.php?qn_id=375094&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._