1. Clinical Overview
Iron (50mg) is a therapeutic dose of elemental iron, primarily as ferrous salts (sulfate, fumarate, gluconate), used for the treatment and prevention of iron deficiency anemia (IDA). In the Indian context, IDA is highly prevalent, especially among women of reproductive age, pregnant women, adolescents, and children. This dose provides a substantial amount of elemental iron to replenish depleted iron stores and support hemoglobin synthesis. Oral iron therapy is the first-line treatment for uncomplicated IDA.
| Onset | Duration | Bioavailability |
|---|---|---|
| Reticulocyte response begins in 3-5 days. Hemoglobin levels typically start rising within 2-4 weeks of therapy. | Duration depends on the severity of deficiency. Treatment is usually continued for 3-6 months after hemoglobin normalizes to replenish iron stores. | Approximately 5-15% in iron-deficient individuals. Absorption is highly variable and influenced by dietary factors, gastric pH, and formulation. |
2. Mechanism of Action
Iron is an essential component of hemoglobin, the oxygen-carrying protein in red blood cells. In iron deficiency, hemoglobin synthesis is impaired, leading to microcytic, hypochromic anemia. Oral iron supplements provide elemental iron, which is absorbed in the duodenum and proximal jejunum via divalent metal transporter 1 (DMT1). It is then oxidized to ferric iron (Fe3+), bound to transferrin, and transported to bone marrow for incorporation into heme, the prosthetic group of hemoglobin. This restores normal erythropoiesis.
3. Indications & Uses
- Iron Deficiency Anemia (IDA)
- Prophylaxis of iron deficiency in high-risk groups (pregnancy, menorrhagia, chronic blood loss)
4. Dosage & Administration
Adult Dosage: For treatment of IDA: 50-100 mg of elemental iron twice daily (total 100-200 mg/day). For prophylaxis: 50 mg once daily. Doses are typically divided to improve tolerance and absorption.
Administration: Take on an empty stomach (1 hour before or 2 hours after meals) for maximum absorption. If GI upset occurs, take with a small amount of food. Avoid taking with tea, coffee, milk, calcium supplements, or antacids, as they inhibit absorption. May be taken with Vitamin C (ascorbic acid) or orange juice to enhance absorption. Do not crush or chew enteric-coated or sustained-release tablets.
5. Side Effects
Common side effects may include:
- Nausea
- Epigastric pain
- Constipation (very common in Indian population)
- Diarrhea (less common)
- Dark-colored or black stools (benign)
- Heartburn
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Antacids (Aluminum, Magnesium, Calcium) | Decreased iron absorption due to increased pH and formation of insoluble complexes. | Major |
| Tetracycline, Doxycycline, Ciprofloxacin | Decreased absorption of both iron and the antibiotic due to chelation. Administer at least 2-3 hours apart. | Major |
| Levothyroxine | Decreased absorption of levothyroxine. Administer at least 4 hours apart. | Major |
| Cholestyramine | Decreased iron absorption. | Moderate |
| Vitamin C (Ascorbic Acid) | Increased absorption of non-heme iron. | Minor (Beneficial) |
| Penicillamine | Decreased absorption of penicillamine. | Moderate |
| Methyldopa | Decreased absorption and potentially decreased efficacy of methyldopa. | Moderate |
| Proton Pump Inhibitors (Omeprazole) | Decreased iron absorption due to reduced gastric acidity. | Moderate |
7. Patient Counselling
- DO take on an empty stomach for best absorption.
- DO take with Vitamin C (orange juice) if GI tolerated.
- DO expect stools to turn dark green or black; this is normal.
- DO store safely away from children; iron overdose can be fatal.
- DON'T take with tea, coffee, milk, or antacids.
- DON'T crush or chew enteric-coated tablets.
- DON'T take with calcium supplements; space by 2 hours.
- DO inform your doctor if you experience severe constipation, vomiting, or abdominal pain.
8. Toxicology & Storage
Overdose: Acute: Nausea, vomiting (often bloody), diarrhea, abdominal pain, lethargy, metabolic acidosis, hypovolemic shock, coagulopathy, hepatic necrosis, and multi-organ failure. Stages: GI (0-6 hrs), Latent (6-24 hrs), Systemic/Cardiovascular collapse (12-48 hrs). Chronic: Hemosiderosis, organ damage (liver, heart, pancreas).
Storage: Store in a cool, dry place below 30°C. Protect from light and moisture. Keep in the original container, tightly closed. Keep out of reach and sight of children. Do not use after the expiry date printed on the pack.