Desferal

deferoxamine

(de-fer-ox-a-meen) deferoxamine,

Desferal

(trade name)

Classification

Therapeutic: antidotes
Pharmacologic: heavy metal antagonists
Pregnancy Category: C

Indications

Acute toxic iron ingestion.Secondary iron overload syndromes associated with multiple transfusion therapy.

Action

Chelates unbound iron, forming a water-soluble complex (ferrioxamine) in plasma that is easily excreted by the kidneys.

Therapeutic effects

Removal of excess iron. Also chelates aluminum.

Pharmacokinetics

Absorption: Poorly absorbed after oral administration. Well absorbed after IM administration and subcut administration.Distribution: Appears to be widely distributed.Metabolism and Excretion: Metabolized by tissues and plasma enzymes. Unchanged drug and chelated form excreted by the kidneys; 33% of iron removed is eliminated in the feces via biliary excretion.Half-life: 1 hr.

Time/action profile (effects on hematologic parameters)

ROUTEONSETPEAKDURATION
IVrapidunknownunknown
IMunknownunknownunknown
Subcutunknownunknownunknown

Contraindications/Precautions

Contraindicated in: Severe renal disease;Anuria; Obstetric: Early pregnancy or child-bearing potential (however, may be used safely in pregnant patients with moderate-to-severe acute iron intoxication).Use Cautiously in: Pediatric: Children <3 yr (safety not established).

Adverse Reactions/Side Effects

Ear, Eye, Nose, Throat

  • blurred vision
  • cataracts
  • ototoxicity

Cardiovascular

  • hypotension
  • tachycardia

Gastrointestinal

  • abdominal pain
  • diarrhea

Genitourinary

  • red urine (most frequent)

Dermatologic

  • erythema
  • flushing
  • urticaria

Local

  • induration at injection site
  • pain at injection site

Musculoskeletal

  • leg cramps

Miscellaneous

  • allergic reactions
  • fever
  • shock after rapid IV administration

Interactions

Drug-Drug interaction

Ascorbic acid may ↑ effectiveness of deferoxamine but may also ↑ cardiac iron toxicity.

Route/Dosage

Acute Iron IngestionIntramuscular Intravenous (Adults and Children ≥3 yr) 1 g, then 500 mg q 4 hr for 2 doses. Additional doses of 500 mg q 4–12 hr may be needed (not to exceed 6 g/24 hr).Chronic Iron OverloadIntramuscular Intravenous (Adults and Children ≥3 yr) 500 mg–1 g daily IM; additional doses of 2 g should be given IV for each unit of blood transfused (not to exceed 1 g/day in absence of transfusions; 6 g/day if patient receives transfusions).Subcutaneous (Adults and Children ≥3 yr) 1–2 g/day (20–40 mg/kg/day) infused over 8–24 hr.

Availability (generic available)

Powder for injection: 500 mg/vial, 2 g/vial

Nursing implications

Nursing assessment

  • In acute poisoning, assess time, amount, and type of iron preparation ingested.
  • Monitor signs of iron toxicity: early acute (abdominal pain, bloody diarrhea, emesis), late acute (decreased level of consciousness, shock, metabolic acidosis).
  • Monitor vital signs closely, especially during IV administration. Report hypotension, erythema, urticaria, or signs of allergic reaction. Keep epinephrine, an antihistamine, and resuscitation equipment close by in the event of an anaphylactic reaction.
  • May cause oculotoxicity or ototoxicity. Report decreased visual acuity or hearing loss. Audiovisual exams should be performed every 3 mo in patients with chronic iron overload.
  • Monitor intake and output and urine color. Inform health care professional if patient is anuric. Chelated iron is excreted primarily by the kidneys; urine may turn red.
  • Lab Test Considerations: Monitor serum iron, total iron binding capacity (TIBC), ferritin levels, and urinary iron excretion before and periodically during therapy.
    • Monitor liver function studies to assess damage from iron poisoning.

Potential Nursing Diagnoses

Risk for injurypoisoning (Indications)

Implementation

  • IM route is preferred in acute iron intoxication unless patient is in shock.
    • Reconstitute 500-mg vial with 2 mL and 2-g vial with 8 mL of sterile water for injection for a concentration of 213 mg/mL. Dissolve powder completely before administration. Solution is yellow and is stable for 1 wk after reconstitution if protected from light. Discard unused portion.
    • Used in conjunction with induction of emesis or gastric aspiration and lavage with sodium bicarbonate, and supportive measures for shock and metabolic acidosis in acute poisoning.
  • Intramuscular: Administer deep IM and massage well. Rotate sites. IM administration may cause transient severe pain.
  • Subcutaneous: Reconstitute 500-mg vial with 5 mL and 2-g vial with 20 mL of sterile water for injection. Concentration: 95 mg/mL. Subcut route used to treat chronically elevated iron therapy is administered into abdominal subcut tissue via infusion pump for 8–24 hr per treatment.
  • Intravenous: Reconstitute 500-mg vial with 5 mL and 2-g vial with 20 mL of sterile water for injection. Concentration: 95 mg/mL. Diluent: D5W, 0.9% NaCl, 0.45% NaCl, or LR. Dissolve powder completely before administration. Solution is clear and colorless to slightly yellow. Administer within 3 hr of reconstitution; 24 hr if prepared under laminar flow hood. Discard unused portion.
  • Rate: Maximum infusion rate is 15 mg/kg/hr for first 1000 mg. May be followed by 500 mg infused over 4 hr at a slower rate not to exceed 125 mg/hr. Rapid infusion rate may cause hypotension, erythema, urticaria, wheezing, convulsions, tachycardia, or shock.
    • May be administered at the same time as blood transfusion in persons with chronically elevated serum iron levels. Use separate site for administration.

Patient/Family Teaching

  • Reinforce need to keep iron preparations, all medications, and hazardous substances out of the reach of children.
  • Reassure patient that red coloration of urine is expected and reflects excretion of excess iron.
  • May cause dizziness or impairment of vision or hearing. Caution patient to avoid driving or other activities requiring alertness until response from medication is known.
  • Advise patient not to take vitamin C preparations without consulting health care professional, because tissue toxicity may increase.
  • Encourage patients requiring chronic therapy to keep follow-up appointments for lab tests. Eye and hearing exams may be monitored every 3 mo.

Evaluation/Desired Outcomes

  • Return of serum iron concentrations to a normal level (50–150 mcg/100 mL).

Desferal

A brand name for DESFERRIOXAMINE.