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 is a chewable tablet that binds dietary phosphate in the upper gastrointestinal tract, forming insoluble lanthanum phosphate complexes that are excreted in feces, thereby reducing serum phosphate and calcium-phosphate product.
| Onset | Duration | Bioavailability |
|---|---|---|
| The phosphate-lowering effect begins with the first dose, but clinically significant reductions in serum phosphate are typically observed within 1-2 weeks of consistent dosing with meals. | The therapeutic effect is meal-dependent, lasting for the duration of digestion. Serum phosphate control requires continuous administration with each meal. | <0.002% (essentially negligible). Systemic absorption of lanthanum is extremely low. |
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-) present in ingested food, 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 Chronic Kidney Disease (CKD) Stage 5 (End-Stage Renal Disease - ESRD) on dialysis (hemodialysis or peritoneal dialysis).
4. Dosage & Administration
Adult Dosage: Initial: 500 mg (one tablet) chewed with or immediately after each meal. Titrate based on serum phosphate levels. Usual therapeutic dose: 1500-3000 mg per day, divided and administered with meals. Doses up to 3750 mg/day have been used.
Administration: CHEW TABLETS COMPLETELY BEFORE SWALLOWING. Do not swallow whole. Must be taken WITH or IMMEDIATELY AFTER food to bind dietary phosphate effectively. If a meal is missed, the corresponding dose should be omitted. Tablets can be crushed for patients with chewing difficulties. Maintain adequate interval (at least 2 hours) from other oral medications (especially tetracyclines, quinolones, levothyroxine) to prevent 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 |
|---|---|---|
| Tetracycline antibiotics (Doxycycline, Tetracycline) | Lanthanum binds to tetracycline in GI tract, significantly reducing its absorption. | Major |
| Fluoroquinolone antibiotics (Ciprofloxacin, Levofloxacin) | Lanthanum binds to quinolones, reducing their absorption and efficacy. | Major |
| Levothyroxine | Lanthanum may bind to levothyroxine, reducing its absorption. | Major |
| ACE Inhibitors (e.g., Enalapril) | No direct interaction, but both can cause nausea/vomiting; additive GI effects possible. | Moderate |
7. Patient Counselling
- DO chew each tablet completely. Do not swallow it whole.
- DO take the tablet with or immediately after every meal or snack.
- DO inform all your doctors and your dentist that you are taking this medicine, especially before any X-ray.
- DO separate the timing of this medicine from other medicines (at least 2 hours before or after).
- DON'T take a dose if you skip a meal.
- DON'T crush the tablets and mix with food unless advised by your doctor, and consume the entire mixture.
8. Toxicology & Storage
Overdose: Acute overdose is unlikely to cause systemic toxicity due to minimal absorption. Expected effects would be an extension of GI side effects: severe nausea, vomiting, constipation, or diarrhea. Risk of hypophosphatemia with chronic overuse.
Storage: Store below 30°C. Protect from moisture. Keep in the original blister pack or container. Keep out of reach of children.