1. Clinical Overview
Lanthanum carbonate is a non-calcium, non-aluminum phosphate binder indicated for the reduction of hyperphosphatemia in patients with end-stage renal disease (ESRD) on hemodialysis or peritoneal dialysis. It acts by binding dietary phosphate in the gastrointestinal tract, forming insoluble lanthanum phosphate complexes that are excreted in feces, thereby reducing serum phosphate absorption.
| Onset | Duration | Bioavailability |
|---|---|---|
| Reduction in serum phosphate levels can be observed within 1-2 weeks of starting therapy. | The phosphate-binding effect is localized to the GI tract and lasts for the duration of transit, requiring administration with meals. Serum phosphate control is maintained with chronic dosing. | <0.002% (essentially negligible systemic absorption). |
2. Mechanism of Action
Lanthanum carbonate dissociates in the acidic environment of the stomach, releasing lanthanum ions (La3+). These trivalent cations bind directly to dietary phosphate anions (PO4^3-) within the lumen of the upper gastrointestinal tract (stomach and proximal small intestine), forming highly insoluble lanthanum phosphate complexes (LaPO4). This complex is not absorbed and is excreted in the feces, thereby preventing the absorption of dietary phosphate and lowering serum phosphate levels.
3. Indications & Uses
- Reduction of hyperphosphatemia in adult patients with End-Stage Renal Disease (ESRD) on dialysis (hemodialysis or peritoneal dialysis).
4. Dosage & Administration
Adult Dosage: Initial: 250-500 mg (1-2 tablets of 250mg) three times daily with meals. Titrate every 2-3 weeks based on serum phosphate levels. Usual maintenance: 500-1500 mg per day in divided doses with meals. Maximum clinical experience is up to 3750 mg/day.
Administration: Tablets MUST be chewed completely before swallowing. Do not swallow whole. Should be taken with or immediately after food to maximize binding to dietary phosphate. If a meal is missed, the corresponding dose should be omitted. Can be crushed for patients with chewing difficulties. Maintain adequate interval (at least 2 hours) from administration of other oral medications (e.g., levothyroxine, quinolones, tetracyclines) to avoid binding and reduced absorption.
5. Side Effects
Common side effects may include:
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Abdominal pain
- Dyspepsia
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Levothyroxine | Lanthanum binds to levothyroxine, significantly reducing its absorption. | Major |
| Ciprofloxacin, Levofloxacin | Reduced absorption of quinolone antibiotics. | Major |
| Tetracycline, Doxycycline | Reduced absorption of tetracycline antibiotics. | Major |
| Oral Bisphosphonates (Alendronate) | Reduced absorption of bisphosphonate. | Major |
| ACE Inhibitors/ARBs, Beta-blockers | No clinically significant interaction expected. | Minor |
7. Patient Counselling
- DO chew tablets completely. Do not swallow whole.
- DO take with or immediately after meals.
- DO inform your doctor about all other medications you are taking.
- DO maintain your prescribed renal diet (low phosphate).
- DONT take it if you have missed a meal.
- DONT take other medicines within 2 hours of taking lanthanum carbonate.
8. Toxicology & Storage
Overdose: Acute overdose may lead to severe nausea, vomiting, constipation, and abdominal pain. Risk of hypophosphatemia with chronic excessive dosing.
Storage: Store below 30°C. Protect from moisture. Keep in the original blister pack or container. Keep out of reach of children.