Fosrenol

lanthanum carbonate

Fosrenol

Pharmacologic class: Phosphate binder

Therapeutic class: Renal and genitourinary agent

Pregnancy risk category C

Action

Dissociates in acidic environment of upper GI tract to release lanthanum ions, which bind dietary phosphate released from food during digestion and inhibit phosphate absorption by forming highly insoluble lanthanum phosphate complexes

Availability

Tablets (chewable): 500 mg, 750 mg, 1,000 mg

Indications and dosages

➣ To reduce serum phosphate level in patients with end-stage renal disease

Adults: Initially, 1,500 mg P.O. (chewed) daily in divided doses with meals; titrate every 2 to 3 weeks until serum phosphate falls to acceptable level.

Contraindications

• Bowel obstruction, ileus, or fecal impaction

Precautions

Use cautiously in:

• acute peptic ulcer, Crohn's disease, ulcerative colitis

• pregnant or breastfeeding patients

• children (safety and efficacy not established).

Administration

• Give before meals; ensure that patient chews tablets completely before swallowing to reduce risk of serious adverse GI events.

Adverse reactions

CNS: headache

CV: hypotension

GI: nausea, vomiting, diarrhea, constipation, abdominal pain

Metabolic: hypercalcemia

Respiratory: bronchitis, rhinitis

Other: dialysis graft complication or occlusion

Interactions

Drug-diagnostic tests. Serum calcium: increased

Patient monitoring

• Monitor serum calcium and phosphorus levels periodically.

Patient teaching

• Instruct patient to take drug with or immediately after meals and to chew tablets completely before swallowing.

• Advise patient to discuss any planned dietary changes with prescriber.

• Inform female patient with childbearing potential that drug isn't recommended during pregnancy.

• Instruct female patient to tell prescriber if she's breastfeeding.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the tests mentioned above.

lanthanum carbonate

(lan-than-um) lanthanumcarbonate,

Fosrenol

(trade name)

Classification

Therapeutic: hypophosphatemics
Pharmacologic: phosphate binders
Pregnancy Category: C

Indications

Reduction of serum phosphate levels associated with end-stage renal disease.

Action

Dissociates in the upper GI tract forming lanthanate ions, which form an insoluble complex with phosphate.

Therapeutic effects

Decreased serum phosphate levels.

Pharmacokinetics

Absorption: Negligible absorption.Distribution: Stays within the GI tract.Metabolism and Excretion: Eliminated almost entirely in feces.Half-life: 53 hr (in plasma).

Time/action profile (effect on phosphate levels)

ROUTEONSETPEAKDURATION
POunknown2–3 wkunknown

Contraindications/Precautions

Contraindicated in: Bowel obstruction;Ileus;Fecal impaction; Obstetric: Congenital abnormalities noted in animal studies; Pediatric: Potential negative effect on developing bone.Use Cautiously in: Patients with risk factors for bowel obstruction, including history of GI surgery, colon cancer, constipation, ileus, diabetes, or taking medications that cause constipation; Lactation: Safety not established.

Adverse Reactions/Side Effects

Gastrointestinal

  • nausea (most frequent)
  • vomiting (most frequent)
  • diarrhea
  • fecal impaction
  • GI obstruction
  • ileus

Fluid and Electrolyte

  • hypocalcemia

Interactions

Drug-Drug interaction

May ↓ abosrption of fluoroquinolones, tetracyclines, and levothyroxine ; administer at least 1 hr before or 3 hr after lanthanum carbonate.

Route/Dosage

Oral (Adults) 1500 mg/day in divided doses; may be titrated upward every 2–3 wk in increments of 750 mg/day up to 4500 mg/day (usual range 1500–3000 mg/day).

Availability

Chewable tablets: 500 mg, 750 mg, 1000 mg

Nursing implications

Nursing assessment

  • Assess patient for nausea and vomiting during therapy.
  • Lab Test Considerations: Monitor serum phosphate levels prior to and periodically during therapy.

Potential Nursing Diagnoses

Nausea (Side Effects)

Implementation

  • Do not confuse lanthanum carbonate with lithium carbonate.
  • Divide total daily dose and administer with meals.
  • Oral: Administer with or immediately after meals. Tablets should be crushed or chewed completely before swallowing; intact tablets should not be swallowed.

Patient/Family Teaching

  • Instruct patient to take lanthanum as directed.

Evaluation/Desired Outcomes

  • Decrease in serum phosphate to below than 6.0 mg/dL in patients with end stage renal disease.