de-fer-OX-a-meen

Therapeutic Classification: antidotes

Pharmacologic Classification: heavy metal antagonists

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

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

• Removal of excess iron. Also chelates aluminum.

Absorption: Poorly absorbed after oral administration. Well absorbed after IM administration and SUBQ administration. IV administration results in complete bioavailability.

Distribution: Appears to be widely distributed.

Metabolism/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.

(effects on hematologic parameters)

Contraindicated in:

• Severe renal impairment
• Anuria
• Lactation: Lactation.

Use Cautiously in:

• OB: Safety not established in pregnancy. Treatment should not be withheld in pregnant women with acute iron toxicity
• Pedi: Children <3 yr (safety and effectiveness not established).

CV: hypotension, tachycardia.

Derm: erythema, flushing, urticaria.

EENT: blurred vision, cataracts, ototoxicity.

GI: abdominal pain, diarrhea.

GU: red urine.

Local: induration at injection site, pain at injection site.

MS: leg cramps.
Misc: fever, (INCLUDING ANAPHYLAXIS)HYPERSENSITIVITY REACTIONS , shock (after rapid IV administration).

Drug-Drug:

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

Acute Iron Ingestion

• IM, IV (Adults and Children 3 yr): 1 g, then 500 mg every 4 hr for 2 doses. Additional doses of 500 mg every 4–12 hr may be needed (not to exceed 6 g/24 hr).

Chronic Iron Overload

• IM, IV (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).
• SC (Adults and Children 3 yr): 1–2 g/day (20–40 mg/kg/day) infused over 8–24 hr.

(Generic available)

• Powder for injection: 500 mg/vial; 2 g/vial;

• 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.

• 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.

• IM route is preferred in acute iron intoxication unless patient is in shock.
  • Reconstitution: Reconstitute 500-mg vial with 2 mL and 2-g vial with 8 mL of sterile water for injection. Dissolve powder completely before administration. Solution is yellow and is stable for 1 wk after reconstitution if protected from light. Discard unused portion. 213 mg/mL.
  • 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.
• IM: Administer deep IM and massage well. Rotate sites. IM administration may cause transient severe pain.
• SC: Reconstitute 500-mg vial with 5 mL and 2-g vial with 20 mL of sterile water for injection. 95 mg/mL. SUBQ route used to treat chronically elevated iron therapy is administered into abdominal SUBQ tissue via infusion pump for 8–24 hr per treatment.

IV Administration:

• IV: Reconstitution: Reconstitute 500-mg vial with 5 mL and 2-g vial with 20 mL of sterile water for injection. 95 mg/mL. 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.

• 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.
• Advise females of reproductive potential to notify health care professional if pregnancy is planned. Breastfeeding should be avoided during therapy and for 1 wk after the last dose.

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

Desferal