A 42-year-old woman with iron deficiency anemia has been on oral ferrous sulfate 200 mg once daily for 8 weeks. Her hemoglobin remains 8.2 g/dL (baseline 7.8 g/dL), and she reports persistent nausea and abdominal discomfort. Serum ferritin is 15 ng/mL. Compliance with medication is confirmed. What is the most appropriate next step in management?

Explanation

## Clinical Problem: Iron Therapy Failure **Key Point:** Failure to respond to oral iron therapy (Hb rise <1 g/dL in 4 weeks) with documented compliance indicates either: 1. Ongoing blood loss exceeding replacement 2. Malabsorption (celiac disease, H. pylori, achlorhydria) 3. Intolerance necessitating IV iron **High-Yield:** This patient has: - Minimal Hb rise (0.4 g/dL over 8 weeks = failure to respond) - Persistent GI symptoms (nausea, abdominal discomfort) → intolerance - Confirmed compliance - Persistent low ferritin (15 ng/mL) → ongoing iron depletion ## Management Algorithm for Oral Iron Failure ```mermaid flowchart TD A[IDA on oral iron] --> B{Hb rise ≥1 g/dL in 4 weeks?} B -->|Yes| C[Continue oral iron] B -->|No| D{Compliance confirmed?} D -->|No| E[Reassess adherence] D -->|Yes| F{GI intolerance?} F -->|Yes| G[Switch to IV iron] F -->|No| H[Investigate malabsorption] G --> I[IV iron sucrose 200 mg weekly] H --> J[Celiac serology, H. pylori, B12/folate] ``` ## Oral Iron Intolerance Management | Feature | Action | |---------|--------| | **GI side effects** (nausea, cramping, constipation) | Switch to IV iron | | **Malabsorption suspected** | Investigate before IV iron | | **IV iron choice** | Iron sucrose preferred (safer than dextran) | | **IV iron dosing** | 200 mg weekly × 4–5 weeks | | **Concurrent investigation** | Celiac serology, H. pylori, B12/folate if not already done | **Clinical Pearl:** IV iron sucrose is safer than iron dextran (lower anaphylaxis risk) and preferred in India. It bypasses GI absorption and achieves faster repletion. **Warning:** Do NOT simply increase oral iron dose in an intolerant patient—this worsens GI symptoms and delays effective treatment. IV iron is the correct escalation step.