ferrous gluconate
Apo-Ferrous Gluconate ◆, Fergon, Ferralet, Fertinic ◆, Novoferrogluc ◆, Simron

Available forms
Available without a prescription. Ferrous gluconate is 11.6% elemental iron.
Capsules: 86 mg (contains 10 mg Fe⁺), 325 mg (contains 38 mg Fe⁺)
Elixir: 300 mg/5 ml (contains 35 mg Fe⁺)
Tablets: 300 mg (contains 35 mg Fe⁺), 320 mg (contains 37 mg Fe⁺), 325 mg

Indications and dosages
 Iron deficiency. Adults: 100 to 200 mg elemental iron P.O. t.i.d.
Children ages 2 to 12: 3 mg/kg P.O. daily in three or four divided doses.
Children ages 6 months to 2 years: Up to 6 mg/kg P.O. daily in three or four divided doses.
Infants: 10 to 25 mg P.O. daily divided into three or four doses.
Elderly patients: May need higher doses because reduced gastric secretions and achlorhydria may lower their capacity for iron absorption.

Pharmacodynamics
Hematinic action: Ferrous gluconate replaces iron, an essential component in the formation of hemoglobin.

Pharmacokinetics
Absorption: Absorbed from the entire length of the GI tract, but primary absorption sites are the duodenum and proximal jejunum. Up to 10% of iron is absorbed by healthy individuals; patients with iron-deficiency anemia may absorb up to 60%. Food may decrease absorption by 33% to 50%.
Distribution: Transported through GI mucosal cells directly into the blood, where it is immediately bound to a carrier protein, transferrin, and transported to the bone marrow for incorporation into hemoglobin. Iron is highly protein-bound.
Metabolism: Liberated by the destruction of hemoglobin but is conserved and reused by the body.
Excretion: Healthy people lose only small amounts of iron daily. Men and postmenopausal women lose about 1 mg/day, premenopausal women about 1.5 mg/day. Loss usually occurs in nails, hair, feces, and urine; trace amounts are lost in bile and sweat.

Contraindications and precautions
Contraindicated in patients receiving repeated blood transfusions and those with peptic ulceration, regional enteritis, ulcerative colitis, hemosiderosis, primary hemochromatosis, or hemolytic anemia unless iron deficiency anemia is also present. Use cautiously on long-term basis.

Interactions
Drug-drug. Antacids, aluminum-containing phosphate binders, cholestyramine, cimetidine, vitamin E: Decreases ferrous fumarate absorption. Separate doses by 1- to 2-hour intervals.
Chloramphenicol: Increases response to iron therapy. Monitor patient carefully.
Doxycycline: May interfere with ferrous fumarate absorption even when doses are separated. Avoid use together.
L-thyroxine: May decrease L-thyroxine absorption. Separate doses by at least 2 hours. Monitor thyroid function.
Levodopa, methyldopa: May decrease absorption of these drugs. Monitor patient carefully.
Penicillamine: Decreases penicillamine absorption. Separate doses by at least 2 hours.
Quinolones: May decrease quinolone absorption. Monitor patient closely.
Tetracycline: Inhibits absorption of both drugs. Give tetracycline 3 hours after or 2 hours before iron supplement.
Vitamin C: Increases iron absorption. May be used as a beneficial drug interaction.
Drug-herb. Black cohosh, chamomile, feverfew, gossypol, hawthorn, nettle, plantain, St. John’s wort: Decreases iron absorption. Discourage use together.
Drug-food. Cereals, cheese, coffee, eggs, milk, tea, whole-grain breads, yogurt: May impair oral iron absorption. Discourage use together.

Adverse reactions
GI: nausea, epigastric pain, vomiting, constipation, diarrhea, black stools, anorexia.
Other: temporary staining of teeth (with elixir).

Effects on lab test results
None reported.

Overdose and treatment
The lethal dose of iron is between 200 and 250 mg/kg; fatalities have occurred with lower doses. Signs and symptoms may follow ingestion of 20 to 60 mg/kg. Between 30 minutes and 8 hours after ingestion, patient may experience lethargy, nausea, vomiting, green and then tarry stools, weak and rapid pulse, hypotension, dehydration, acidosis, and coma. If death doesn’t immediately ensue, symptoms may clear for about 24 hours. At 12 to 48 hours, symptoms may return, accompanied by diffuse vascular congestion, pulmonary edema, shock, seizures, anuria, and hyperthermia. Death may follow.
 Treatment requires immediate support of airway, breathing, and circulation. In conscious patient with intact gag reflex, induce emesis with ipecac; otherwise, empty stomach by gastric lavage. Follow emesis with lavage, using a 1% sodium bicarbonate solution, to convert iron to less irritating, poorly absorbed form (phosphate solutions have been used but carry hazard of other adverse effects). Take abdominal X-ray to determine continued presence of excess iron; if serum iron levels exceed 350 mg/dl, deferoxamine may be used for systemic chelation.
 Survivors are likely to sustain organ damage, including pyloric or antral stenosis, hepatic cirrhosis, CNS damage, and intestinal obstruction.

Special considerations
• Ferrous gluconate blackens feces and may interfere with test for occult blood in the stools; the guaiac test and orthotoluidine test may yield false-positive results, but the benzidine test is usually not affected.
• Iron overload may decrease uptake of technetium 99m and thus interfere with skeletal imaging.
• Drug can be given between meals or with some food, but absorption may be decreased.
Breast-feeding patients
• Iron supplements are commonly recommended for breast-feeding women; no adverse effects have been documented.
Pediatric patients
• Overdose may be fatal in children; treat immediately.
Geriatric patients
• Iron-induced constipation is common in elderly patients; stress proper diet or prescribe a stool softener.

Patient education
• To promote absorption, tell patient to take tablets with orange juice.
 ALERT Inform parents that as few as three tablets can cause poisoning in children. Caution parents to store drug securely away from children.
• Caution patient not to substitute one iron salt for another because the amounts of elemental iron vary.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use