Usage
Lanthanum Carbonate is prescribed to reduce serum phosphate levels in patients with end-stage renal disease (ESRD). It belongs to the pharmacological classification of phosphate binders. This medication works by binding to dietary phosphate in the gastrointestinal tract, preventing its absorption into the bloodstream. This action helps lower the elevated phosphate levels commonly seen in patients with ESRD.
Alternate Names
The generic name is Lanthanum Carbonate. A popular brand name under which it’s marketed is Fosrenol. Other possible names include lanthanum carbonate dihydrate and lanthanum carbonate hydrate.
How It Works
Pharmacodynamics: Lanthanum Carbonate acts locally in the gut lumen by binding to dietary phosphate, forming insoluble lanthanum phosphate complexes. These complexes are then excreted in the feces, thereby reducing the amount of phosphate absorbed into the body.
Pharmacokinetics:
- Absorption: Lanthanum is minimally absorbed systemically. Less than 0.002% of an oral dose is absorbed.
- Metabolism: Lanthanum Carbonate is not metabolized.
- Elimination: Almost all ingested lanthanum is eliminated in the feces as insoluble lanthanum phosphate. The small fraction absorbed systemically is primarily eliminated through biliary excretion.
Mode of Action: Lanthanum’s mode of action involves direct chemical binding to phosphate within the GI tract. It doesn’t involve receptor binding, enzyme inhibition, or neurotransmitter modulation.
Dosage
Standard Dosage
Adults:
- Initial dose: 1500 mg/day orally in divided doses with meals.
- Titration: Increase the dose in 750 mg increments every 2-3 weeks until the desired serum phosphate level (typically < 6 mg/dL) is achieved.
- Maintenance dose: Most patients require 1500 to 3000 mg/day.
- Maximum dose: 4500 mg/day, though doses up to 3750 mg have been studied.
Children:
Use is not recommended in children under 18 years of age as safety and efficacy have not been established.
Special Cases:
- Elderly Patients: No dosage adjustment is typically required. However, careful monitoring is recommended.
- Patients with Renal Impairment: No dosage adjustment is needed as the drug is intended for patients with ESRD.
- Patients with Hepatic Dysfunction: No dosage adjustment is required, but careful monitoring is advised.
- Patients with Comorbid Conditions: Dose adjustments may be needed for specific conditions. Consult drug interaction information before prescribing.
Clinical Use Cases
Dosage recommendations are the same across clinical settings involving ESRD patients, including those requiring intubation, surgical procedures, mechanical ventilation, ICU care, and emergency situations. The focus remains on controlling serum phosphate levels.
Dosage Adjustments
Dose modifications should be based on serum phosphate levels. Regular monitoring of serum phosphate is essential to ensure effective management.
Side Effects
Common Side Effects
- Nausea
- Vomiting
- Diarrhea
- Stomach pain
- Constipation
Rare but Serious Side Effects
- Severe allergic reactions (hives, difficulty breathing, swelling)
- Severe constipation or bowel obstruction
- Intestinal perforation
Long-Term Effects
- Lanthanum deposition in bone tissue has been observed in animal studies. The clinical significance in humans is uncertain.
Adverse Drug Reactions (ADR)
Severe gastrointestinal issues like bowel obstruction and perforation require immediate medical attention.
Contraindications
- Known hypersensitivity to lanthanum carbonate
- Bowel obstruction
- Ileus
- Fecal impaction
- Hypophosphatemia
Drug Interactions
Lanthanum Carbonate can decrease the absorption of certain medications taken orally, including some antibiotics (e.g., ciprofloxacin, tetracycline, doxycycline), levothyroxine, and some medications for cholesterol (e.g., atorvastatin, lovastatin). Consult a comprehensive drug interaction resource for details on all potential interactions.
Pregnancy and Breastfeeding
- Pregnancy: Lanthanum carbonate is not recommended for use during pregnancy. Animal studies have shown potential risks to the fetus, though the significance in humans is unknown.
- Breastfeeding: It’s unknown if lanthanum carbonate passes into breast milk. Due to potential risks to the infant, it is recommended to use alternative phosphate binders during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Binds dietary phosphate in the gut, preventing absorption.
- Side Effects: Nausea, vomiting, diarrhea, stomach pain, constipation. Rarely: severe allergic reactions, bowel obstruction, perforation.
- Contraindications: Bowel obstruction, hypersensitivity.
- Drug Interactions: Can reduce absorption of certain oral medications (e.g., some antibiotics, levothyroxine).
- Pregnancy & Breastfeeding: Not recommended during pregnancy. Use alternative during breastfeeding.
- Dosage: Adults: Initial 1500 mg/day divided with meals. Titrate by 750mg every 2-3 weeks up to 4500mg/day or until the target serum phosphate is reached. Not recommended for children.
- Monitoring Parameters: Serum phosphate levels.
Popular Combinations
Lanthanum carbonate is typically used as monotherapy. Combination with other phosphate binders is not common due to increased risk of side effects.
Precautions
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General Precautions: Monitor serum phosphate levels, assess for bowel function, and rule out bowel obstruction before starting therapy. Chew tablets thoroughly or use the oral powder formulation for patients with difficulty chewing.
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Specific Populations: Avoid in pregnancy; not recommended during breastfeeding. Safety and efficacy have not been established in children.
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Lifestyle Considerations: Dietary phosphate restriction is crucial for managing hyperphosphatemia in ESRD patients.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Lanthanum Carbonate?
A: The initial dose is 1500 mg/day orally divided with meals. The dose is titrated every 2–3 weeks until an acceptable serum phosphate level is achieved. The usual maintenance dose is 1500 to 3000 mg/day, with a maximum dose of 4500 mg/day. It’s not recommended for use in children.
Q2: How should Lanthanum Carbonate be administered?
A: Chew tablets thoroughly or crush them before swallowing. The oral powder should be sprinkled on soft food like applesauce and consumed immediately. Always administer with or immediately after meals.
Q3: What is the mechanism of action of Lanthanum Carbonate?
A: It binds to dietary phosphate in the GI tract, forming insoluble complexes that are excreted in feces, preventing phosphate absorption.
Q4: What are the common side effects of Lanthanum Carbonate?
A: Common side effects include nausea, vomiting, diarrhea, stomach pain, and constipation.
Q5: What are the contraindications for Lanthanum Carbonate?
A: Contraindications include bowel obstruction, ileus, fecal impaction, hypophosphatemia, and hypersensitivity to lanthanum.
Q6: Does Lanthanum Carbonate interact with other medications?
A: Yes, it can reduce the absorption of certain oral medications, like some antibiotics, levothyroxine, and some cholesterol-lowering drugs. Consult a drug interaction resource for a comprehensive list.
Q7: Can Lanthanum Carbonate be used during pregnancy or breastfeeding?
A: It’s not recommended for use during pregnancy and should be avoided during breastfeeding due to potential risks to the infant.
Q8: What monitoring is required while a patient is taking Lanthanum Carbonate?
A: Regular monitoring of serum phosphate levels is necessary to assess treatment efficacy and adjust dosage. Monitor for gastrointestinal side effects, especially constipation, as it could indicate a more serious condition.
Q9: What precautions should be taken when prescribing Lanthanum Carbonate to elderly patients?
A: While no specific dosage adjustment is typically necessary for the elderly, they should be monitored closely for adverse events, particularly gastrointestinal issues.
