Pharmacology

Anemias/Iron Deficiency Anemia

Case Study

Patient Profile

Name: Lewis

Age: 3 years old

Gender: male

History of Present Illness

The parents of a three-year-old boy, Lewis, present for review of labs that you ordered due to parental report of Lewis being a “picky eater” and preferring milk over food. The hemogram, also known as the CBC with differential, reveals microcytic, hypochromic red blood cells (RBCs).

Lewis has been playing, eating, drinking, and urinating as usual. There has been no diarrhea or constipation. Lewis has received all scheduled immunizations.

Current Medications

None

Relevant Assessment

Height is 37 inches. Weight today is 31.5 pounds (14.32 kg). Body Mass Index (BMI) is within normal range. Vital signs are stable.

General Appearance: No acute distress, activity normal for age, well developed/well nourished, no cyanosis, pallor, or diaphoresis.

CBC diff completed prior to this office visit, supportive of iron deficiency anemia; hemoglobin 10 g/dL.

No other expanded review of system (subjective data) or examination (objective data) has an impact on the diagnosis reviewed in this case.

Differentials

Iron deficiency anemia, thalassemia, sideroblastic anemias, anemia of chronic disease, and lead poisoning

Diagnosis

Iron deficiency anemia

Diagnostic Testing

None at this time

Referrals

None at this time

Patient/Provider Collaborative Goals

Lewis will have a 1 g/dL improvement in hemoglobin by follow-up visit.

Therapeutic Interventions

  1. Describe a first-line pharmacologic treatment: Include drug name, dose and formulation, frequency, and length of treatment at this dose.
    Answer:

    One option is: Ferrous sulfate 3 mg/kg/day for 12 weeks. The weight of this three-year-old boy is 31.5 lbs (14.2kg). This means the range of dosing for this weight child is 94 mg/day. Prescription: ferrous sulfate (FeroSul) 220 mg/5mL given 2.1 mL daily. For parental ease, you could have them administer 2.0 mL daily; this measurement is easier.

    • Drug Mechanism of Action:
      Answer:

      Ferrous sulfate is a supplemental iron.

    • Contraindications if applicable:
      Answer:

      If a patient has hemochromatosis or hemolytic anemia, ferrous sulfate (FeroSul) is contraindicated. Additionally, an allergy to sulfites and/or tartrazine (FD& C Yellow #5) may be contraindications to some formulations.

  1. Therapeutic advisement and monitoring: (include any specific instructions that apply, such as when to take the medication, if there are foods to avoid, storage issues, etc; include what laboratory/other (i.e., EKG) test monitoring to expect and how often and monitoring for adverse effects both common and serious)
    Answer:

    Specific Instructions: Inform the parents that ferrous sulfate is being used to increase iron in Lewis’s body. Once levels are normal, depending upon his dietary intake, it may be necessary to continue his iron supplements. Tell all healthcare providers involved in Lewis’s care about his iron deficiency anemia and his ferrous sulfate. Ferrous sulfate therapy prevents other drugs from being absorbed into the body, so this is important information to share. Blood work will periodically be done, the frequency of which will be determined by Lewis’s response to treatment and his eating habits.
    Advise parents that the medication can be mixed with water or juice but not milk. Additionally, instruct parents to rinse the child’s mouth with water to avoid staining of teeth.

    • Therapeutic Monitoring: In this situation, the iron deficiency anemia (IDA) is straightforward and consistent with the case presentation making a CBC with diff sufficient for diagnosis. If the cause or type of anemia is in question, then certainly other labs are justified. Up To Date (2025) includes guidance about laboratory testing; if the history is consistent with IDA, perform a limited laboratory evaluation to confirm the presence of microcytic anemia. The extent of the laboratory testing depends on patient characteristics and history. A CBC is sufficient if the presentation is typical for nutritional IDA as in this case (age less than three years, with any dietary risk factors for IDA, and excessive milk intake).
    • Monitor Side/Adverse Effects: The most common side/adverse effects include constipation, diarrhea, stomach pain or cramps, upset stomach, throwing up, feeling less hungry, and change in color of stool to green. The nurse practitioner should ask about these effects at follow-up visits and include these symptoms in patient education.
    • Serious Adverse Effects: Not applicable when utilized in the safe dosing range.
  1. Planned follow-up should consider adverse effect monitoring, dose adjustment considerations, and decisions about continuing versus discontinuing. In this case, planned follow-up would be:
    Answer:

    Follow-up with an office visit in four weeks with CBC diff drawn the day prior to or the morning of the visit.

Review Questions

Click the arrow to expand the section and view the correct answers.

  1. Iron deficiency anemia is common in young children who consume greater than 20 ounces of cow’s milk daily. Which of the following is the correct weight conversion for a 30-pound person?
    1. 13 kilograms
    2. 13.64 kilograms
    3. 15 kilograms
    4. 14 kilograms
Answer:

B. 13.63 kilograms

Feedback: To convert pounds to kilograms, divide the weight in pounds by 2.2. To convert kilograms to pounds, multiply the weight in kilograms by 2.2.

  1. How long after starting a pediatric patient on ferrous sulfate should you expect to see an improvement in hemoglobin if the hemoglobin is between 9 and 11 g/dL?
    1. 1 week
    2. 2 weeks
    3. 4 weeks
    4. 8 weeks
Answer:

C. 4 weeks

Feedback: If a pediatric patient has a microcytic hypochromic anemia with a hemoglobin between 9 and 11 g/dL it is expected that the hemoglobin will rise by 1 g/dL by 4 weeks.

  1. How long after starting a pediatric patient on ferrous sulfate should you expect to see an improvement in hemoglobin if the hemoglobin is less than 9 g/dL?
    1. 1 week
    2. 2 weeks
    3. 4 weeks
    4. 8 weeks
Answer:

B. 2 weeks

Feedback: If a pediatric patient has a microcytic hypochromic anemia with a hemoglobin of less than 9 g/dL, it is expected that the hemoglobin will rise by 1 g/dL by 2 weeks.

  1. Dietary counseling that can be helpful in the treatment of a pediatric patient with iron deficiency anemia may include: (Select all that apply)
    1. Encourage at least 20 ounces of milk consumption per day
    2. Limit milk consumption to 20 ounces per day maximum
    3. Encourage red meat consumption
    4. Limit red meat consumption
    5. Encourage tofu consumption
    6. Limit tofu consumption
    7. Encourage green leafy vegetable consumption
    8. Limit green leafy vegetable consumption
Answer:

B. Limit milk consumption to 20 ounces per day maximum; C) Encourage red meat consumption; E) Encourage tofu consumption; G) Encourage green leafy vegetable consumption.

Feedback: Excess milk consumption is the most common reason for iron deficiency anemia among pediatric patients. Limiting milk consumption to no greater than 20 ounces per day is helpful in encouraging the child to consume other foods, preferentially foods higher in iron content. Red meat, green leafy vegetables, fortified cereal, and tofu are some examples of iron-rich foods.

  1. TRUE/FALSE: Liquid iron formulations can stain teeth.
    1. True
    2. False
Answer:

A. True

Feedback: Liquid iron formulations can stain teeth. Patient education should include interventions to prevent teeth staining, such as mixing the medication with juice or water then having the patient drink it with a straw, or, for very young patients, administering the diluted medication with a dropper and rinsing the mouth after ingestion.

  1. Treatment of megaloblastic (macrocytic cells) anemia may include:
    1. Iron
    2. Folic acid
    3. Vitamin B12
    4. Both B and C
Answer:

D. Both B and C (folic acid and vitamin B12)

Feedback: Megaloblastic anemia is due to vitamin deficiency which can be folate deficiency (folate <2 ng/mL), vitamin B12 deficiency (vitamin B12 < 200 pg/mL), or both. It is important when the hemogram reveals macrocytic cells (MCV) > 100 fL that you follow-up with folate and vitamin B12 serum levels to determine if one or both deficiencies are the cause so you know which vitamins to replace.

  1. Which medication can lead to vitamin B12 deficiency?
    1. Pantoprazole
    2. Lisinopril
    3. Penicillin
    4. Sucralfate
Answer:

A. Pantoprazole

Feedback: Stomach acid is needed to release vitamin B12 from food for absorption; thus, acid suppressing medications like pantoprazole (Protonix) can impair vitamin B12 absorption and lead to deficiency.

  1. Which patient must be treated with folic acid replacement instead of dietary interventions alone for folic acid (folate) deficiency anemia?
    1. A 27-year-old vegan male
    2. A 15-year-old boy with a gaming addiction who does not stop playing long enough to meet nutritional needs but is willing to try eating small meals on a scheduled basis
    3. A 23-year-old female with menorrhagia
    4. A 26-year-old pregnant female
Answer:

D. A 26-year-old pregnant female

Feedback: Folic acid deficiency can lead to neural tube defects of the developing fetus, thus dietary supplementation/increase of folic acid is not sufficient replacement for a pregnant female. Appropriate intake of fruits (including 100% juice) and vegetables may be enough to correct folic acid (folate) deficiency for some patients. A trial of dietary modifications is acceptable for some patients. However, pregnant patients or patients with alcohol use disorder or sprue and intestinal malabsorption disorder need folic acid (folate) replacement therapy.

References

Condina Leik, M. T. (2025). Hematopoietic system review. In FNP Certification Intensive Review (pp. 299–314). Springer Publishing.

Powers, J. M. (2025). Iron deficiency in infants and children <12 years: Screening, prevention, clinical manifestations, and diagnosis. UpToDate®. Retrieved June 9, 2025 from https://www.uptodate.com/contents/iron-deficiency-in-infants-and-children-less-than12-years-screening-prevention-clinical-manifestations-and-diagnosis

Rosenthal, L. D., & Burchum, J. R. (2026). Drugs for deficiency anemias. In Lehne’s pharmacotherapeutics for advanced practice nurses and physician assistants (3rd ed., pp. 385–392). Elsevier.

Up To Date® (2025). Ferrous sulfate: Parent drug information. LexidrugTM. Retrieved June 10, 2025 from https://www.uptodate.com/contents/ferrous-sulfate-patient-drug-information

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Be Prepared for Your Nurse Practitioner Clinical Readiness Exam Copyright © 2026 by Elizabeth Heavey, Renee Biedlingmaier, Colleen Burgoyne and Carnel C. Jackson is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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