lanthanum carbonate
Brand: Fosrenol
Prototype: sevelamer
Drug Class: phosphate binder
Drug Family: electrolyte agent
Subclass: non-calcium rare earth metal phosphate binder
Organ Systems: renal
Mechanism of Action
Lanthanum ions dissociate in the acidic gastric environment and bind dietary phosphate to form highly insoluble lanthanum phosphate complexes that are not absorbed and are excreted in feces; highly potent phosphate binding that is calcium- and aluminum-free.
dietary phosphate (GI lumen)
Indications
- hyperphosphatemia in end-stage renal disease (dialysis patients)
Contraindications
- hypophosphatemia
- bowel obstruction
- hypersensitivity
Adverse Effects
Common
- nausea
- vomiting
- abdominal pain
- diarrhea
- constipation
Serious
- GI obstruction (rare)
- hepatotoxicity (rare)
- long-term tissue accumulation (bone, liver, GI mucosa) — significance uncertain
Pharmacokinetics (ADME)
| Absorption | systemic absorption is minimal (<0.002% of dose); lanthanum accumulates in bone and GI mucosa long-term |
| Distribution | minimally absorbed lanthanum distributes to bone and reticuloendothelial system |
| Metabolism | not hepatically metabolized |
| Excretion | fecal (>99%) as lanthanum phosphate complexes |
| Half-life | N/A for pharmacological action; systemic lanthanum has a very long half-life (years) in tissue |
| Onset | phosphate reduction within weeks |
| Peak | N/A |
| Duration | requires consistent dosing with meals |
| Protein Binding | N/A (GI lumen action) |
| Vd | N/A |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| oral medications generally | lanthanum may bind other oral medications in the GI lumen; separate administration by 2 hours | moderate |
| fluoroquinolones and tetracyclines | metal ion chelation reduces antibiotic absorption | moderate |
Nursing Considerations
- Administer chewable tablets with or immediately after meals; instruct patients to chew tablets thoroughly before swallowing — do not swallow whole.
- Monitor serum phosphate, calcium, and iPTH every 3 months; target serum phosphate 3.5-5.5 mg/dL in dialysis patients per KDIGO guidelines.
- Long-term tissue accumulation of lanthanum (in bone, liver, and GI mucosa) has been documented in post-marketing studies; while clinical significance remains unclear, counsel patients about this phenomenon and report any unusual symptoms.
- Separate lanthanum carbonate from other oral medications by at least 2 hours to minimize GI binding; this is particularly important for fluoroquinolones, tetracyclines, and other drugs affected by metal chelation.
Clinical Pearls
- Lanthanum carbonate requires tablet chewing before swallowing — unlike sevelamer tablets — which affects patient adherence; palatability issues (chalky taste) are the most common reason for non-adherence.
- Among all phosphate binders, lanthanum binds phosphate most potently across the widest pH range (effective in both acidic gastric and neutral intestinal environments), potentially allowing lower pill burden than calcium-based binders.
Safety Profile
Pregnancy avoid
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
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