Red blood cell (RBC) production needs three things: raw materials (iron, vitamin B12, folic acid), a signal from the kidney (erythropoietin), and a working bone marrow. Drugs for anemia replace the missing material or signal. Hematopoietic growth factors also stimulate white cell and platelet production.

Match the drug to the cause: iron deficiency → microcytic; B12 or folate deficiency → macrocytic (megaloblastic); anemia of CKD → low erythropoietin. Always rule out B12 deficiency before giving folic acid alone — folic acid corrects the anemia but lets B12-related nerve damage progress.

Contraindications and cautions

• Iron: hemochromatosis, hemosiderosis, anemia not caused by iron deficiency (e.g., thalassemia without proven deficiency), repeated transfusion with iron overload. IV iron: prior serious reaction to IV iron; avoid in the first trimester of pregnancy and during active infection when possible.
• ESAs: uncontrolled hypertension, pure red cell aplasia after ESA use. In cancer, ESAs are not used when the goal of chemotherapy is cure, and are started only when Hb is below 10 g/dL (100 g/L).
• Filgrastim: do not give within 24 hours before or after cytotoxic chemotherapy (dividing myeloid cells are sensitive).
• Folic acid alone in untreated B12 deficiency.
• Pregnancy: iron and folic acid are standard supplements; ESAs and thrombopoietin agonists are used only if clearly needed. Multidose epoetin vials contain benzyl alcohol — use single-dose vials in pregnancy, lactation, neonates, and infants.

Interactions

• Oral iron absorption is reduced by antacids, calcium, dairy, tea, coffee, high-fiber foods, PPIs and H2 blockers (less acid). Vitamin C (ascorbic acid) increases absorption.
• Iron reduces absorption of levothyroxine, tetracyclines (doxycycline), fluoroquinolones, levodopa, and bisphosphonates — separate doses (commonly by at least 2 hours; 4 hours for levothyroxine).
• Do not give oral iron with IV iron — it adds little and increases GI effects.
• Metformin, PPIs, H2 blockers, colchicine reduce B12 absorption; nitrous oxide inactivates B12.
• Methotrexate, phenytoin, trimethoprim, sulfasalazine, and alcohol reduce folate; folic acid can lower phenytoin levels.
• Eltrombopag binds polyvalent cations — give at least 2 hours before or 4 hours after antacids, dairy, and mineral supplements.

Key laboratory values

Nursing interventions

1. Oral iron: give on an empty stomach (1 hour before meals) with water or juice when tolerated; with food if GI upset (better adherence); liquid iron through a straw, rinse the mouth; reassess Hb in about 4 weeks (an adequate response is a rise of at least about 1 g/dL (10 g/L)).
2. IV iron: check the product and dose; have emergency medications (epinephrine, antihistamine, corticosteroid) and equipment available; observe for at least 30 minutes after the infusion; check vital signs; watch the site closely for extravasation.
3. Iron dextran IM (rarely used): Z-track technique to prevent skin staining; IV route is preferred now.
4. Vitamin B12: deep SC or IM injection; monitor potassium during the first days of treatment of severe anemia; expect neurologic improvement to be slower than blood improvement — some deficits may be permanent.
5. ESAs:
   • Check iron status first (CKD commonly: ferritin > 100 ng/mL (100 µg/L) and transferrin saturation > 20%) — ESAs fail without iron
   • Check BP before each dose; hold and notify for uncontrolled hypertension
   • Hb weekly during dose changes; reduce or hold when Hb approaches 11 g/dL (110 g/L) in CKD or rises more than 1 g/dL in 2 weeks; use the lowest dose that avoids transfusion
   • Do not shake the vial; watch for signs of thrombosis, stroke, seizure
6. Filgrastim/pegfilgrastim: give at least 24 hours after chemotherapy; monitor CBC and ANC (twice weekly during daily filgrastim); treat bone pain (acetaminophen/paracetamol, or antihistamines per order); report left upper abdominal or shoulder pain (splenic rupture); neutropenic precautions continue until counts recover.
7. Eltrombopag: liver tests at baseline and regularly; romiplostim: weekly platelet counts during dose adjustment.

• Iron: take on an empty stomach with a vitamin C source if tolerated; take with food if the stomach is upset; do not take with milk, tea, coffee, antacids, or calcium — separate by about 2 hours; separate from thyroid medicine, doxycycline, and ciprofloxacin
• Expect dark green or black stools; report black tarry stools with abdominal pain or dizziness (possible bleeding)
• Increase fluids, fiber, and activity for constipation; use a straw for liquid iron
• Keep iron tablets locked away and out of children's reach — iron overdose can kill a child
• Iron-rich foods: red meat, liver, poultry, fish, legumes, dark green vegetables, fortified cereals
• Pernicious anemia: B12 injections or high-dose tablets are lifelong; strict vegans need a B12 supplement
• Folic acid: all people who could become pregnant should take 0.4–0.8 mg daily starting before conception
• ESA: keep BP and blood test appointments; report headache, chest pain, leg swelling, sudden weakness, confusion, or seizures; store in the refrigerator; do not shake
• G-CSF at home: SC injection technique; bone pain is common; report fever of 38.0 °C (100.4 °F) or higher, left upper abdominal or shoulder pain, or trouble breathing immediately

Iron poisoning (a leading cause of fatal poisoning in young children)

• Toxic dose (elemental iron): below about 20 mg/kg usually mild; 20–60 mg/kg GI toxicity; > 60 mg/kg serious systemic toxicity
• Stages: (1) 0–6 hours: vomiting, diarrhea, GI bleeding, abdominal pain; (2) 6–24 hours: apparent recovery ("latent phase" — do not be falsely reassured); (3) shock, metabolic acidosis, coagulopathy; (4) liver failure at 2–3 days; (5) weeks later: gastric outlet or bowel scarring and obstruction
• Tests: serum iron 4–6 hours after ingestion; abdominal X-ray may show radiopaque tablets. Serum iron > 500 mcg/dL (about 90 µmol/L) indicates serious toxicity
• Treatment: call poison control; supportive care, IV fluids; activated charcoal does not bind iron; whole-bowel irrigation for visible tablets; deferoxamine IV (chelator) for severe toxicity — urine may turn reddish ("vin rosé"); deferoxamine can cause hypotension if infused too fast, and prolonged use is linked to ARDS

Other

• ESA excess (Hb above target): hypertension, thrombosis, stroke — hold the dose; phlebotomy is rarely needed.
• IV iron hypersensitivity: stop the infusion, assess airway and BP, epinephrine for anaphylaxis.
• Chronic iron overload (repeated transfusions): chelation with deferoxamine, deferasirox, or deferiprone (see Anemias in Medical-Surgical Nursing).
• Vitamin B12 and folic acid are water-soluble with very low toxicity.

• Oral iron: empty stomach + vitamin C; with food if GI upset; black stools are expected
• Separate iron from milk, antacids, calcium, tea, levothyroxine, tetracyclines, fluoroquinolones
• Reticulocytes rise in 7–10 days = first sign of response
• IV iron: observe ≥ 30 minutes for hypersensitivity; extravasation stains skin
• Iron overdose in children → vomiting and GI bleeding, then latent phase, then shock and liver failure; antidote deferoxamine
• Pernicious anemia = no intrinsic factor → lifelong B12 (IM or high-dose oral)
• Rule out B12 deficiency before folic acid alone
• B12 therapy for severe anemia → watch for hypokalemia
• ESAs: check iron and BP first; hold/reduce as Hb approaches 11 g/dL (110 g/L); boxed warning — thrombosis, stroke, death, tumor progression
• Filgrastim: bone pain; splenic rupture (left shoulder pain); not within 24 hours of chemotherapy