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Key points

  • We recommend to consult your poison centre with the use of this antidote.
  • Folic acid should NOT be used as a replacement for leucovorin calcium (folinic acid) in the treatment of dihydrofolate reductase inhibitor intoxication such as methotrexate.
  • Folic acid CAN be used as a replacement for leucovorin calcium (folinic acid) in the treatment of methanol intoxication.
  • Folic acid and leucovorin calcium accelerate the conversion of formates (toxic) to non-toxic metabolites (carbon dioxide and water) obtained from methanol metabolism.

+ Synonyms and other terms

  • Pteroyglutamic acid
  • Vitamin B9
  • Sodium folate

+ Indications

  • Adjuvant in methanol poisoning.

+ Dosage

+ Pediatric Dose

  • In the absence of metabolic acidosis:
    • 1 mg / kg (max: 50mg) by IV infusion over 10 minutes every 6 hours.
  • In the presence of metabolic acidosis:
    • 2 mg / kg (max: 100mg) by IV infusion over 20 minutes every 4 - 6 hours.
    • Adjust the interval based on severity of the acidosis and medical history (malnutrition, alcoholism, etc.).

+ Adult Dose

  • In the absence of metabolic acidosis:
    • 1 mg / kg (max: 50mg) by IV infusion over 10 minutes every 6 hours.
  • In the presence of metabolic acidosis:
    • 2 mg / kg (max: 100mg) by IV infusion over 20 minutes every 4 - 6 hours.
    • Adjust the interval based on severity of the acidosis and medical history (malnutrition, alcoholism, etc.).

+ Renal Impairment

  • No data suggests that the dose should be modified for short-term use.

+ Hepatic Impairment

  • No data suggests that the dose should be modified for short-term use.

+ Hemodialysis Patient

  • Since folic acid is a water-soluble vitamin, a certain amount is expected to be eliminated during hemodialysis.
  • We recommend to give one dose before and one dose at the end of hemodialysis.

+ Pregnancy

  • The safety of high dose folic acid has not been demonstrated.
  • Do not hesitate to use folic acid during pregnancy if the anticipated toxic effects pose a significant risk of morbidity or mortality.
  • No data suggests that the dose should be modified for short-term use.

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+ Obese or Overweight Patient

  • No data suggests that the dose should be modified for short-term use.

+ Adverse effects

  • Allergic and anaphylactoid reactions.
  • Neurological : Agitation, irritability, hyperactivity and impaired judgment have been reported when taking folic acid supplement.
  • Gastric irritation and nausea when given orally.

+ Monitoring

  • No monitoring is required other than the monitoring of the poisoning under treatment.

+ End of treatment

  • When metabolic acidosis has been corrected and when methanol serum concentration is less than 6 mmol/L (19,2 mg/dL).

+ Special Notes on Administration

Intravenous Route (IV)

Direct IV:

  • Administer the diluted (0.1mg/ml) or undiluted solution (5mg/ml) by direct IV at a rate of 5mg/min.
  • Administer using a volumetric pump.
  • Dilution instructions: Dilute 1 ml of the undiluted solution (5mg/ml) with 49 ml of NS, D5W or SWI to obtain a final concentration of 0.1mg/ml.

Subcutaneous Route (SC)

  • Possible alternative to IV route
  • IV route is the preferred route.

Intramuscular Route (IM)

  • Possible alternative to IV route.
  • IV route is the preferred route.

Intraosseous Route (IO)

  • No data available

Oral Route (PO)

  • Possible alternative to IV route
  • Oral and IV doses are equivalent mg to mg
  • Variable degree of absorption when given orally, IV route is the preferred option.

Compatibility

Partial list only. Consult the pharmacist on duty at your health care facility.

  • Compatible solutions: D5W, D20W, NS.
  • Y-site compatibility: alfentanil hydrochloride, aminophylline, ascorbic acid, atropine sulfate, azathioprine sodium, sodium bicarbonate, calcium gluconate, digoxin, diphenhydramine hydrochloride, epinephrine hydrochloride, fentanyl citrate, furosemide, insuline, magnesium sulfate, midazolam hydrochloride, potassium chloride, ranitidine.
  • Y-site incompatibility: amikacin sulfate, calcium chloride, diazepam, morphine sulfate, thiamine hydrochloride. 

Stability

  • Store vials at room temperature between 15 and 30oC
  • Protect form light.
  • Solutions diluted in NS or D5W will be stable for 24 hours at room temperature.

 

 

+ Available products

  • Folic acid 5mg/ml for injection vials of 10ML, BAXTER CORP, DIN 00816086
  • Folic acid 5mg/ml for injection, vials of 10ml, FRESENIUS KABI CANADA LTD, DIN 02139480

+ Amount required to treat a person weighting 70kg during 24 hours

  • 840 mg

+ References

Folic Acid In: DRUGDEX (en ligne) ,Ann Arbor (MI): Truven Health Analytics; c2018. [consulted april 2018] http://www.micromedexsolutions.com/



Ottawa Parenteral Drug Therapy Manual 2010, Folic Acid, p188



Howland, Mary Ann, Folates: Leucovorin (Folinic Acid) and Folic Acid, In Goldfrank’s Toxicologic emergencies, 10th ed, 693-698

 

Kraut, Jeffrey A., and Michael E. Mullins. 2018. “Toxic Alcohols.” The New England Journal of Medicine 378 (3). Massachusetts Medical Society:270–80.


Last updated : 2022-12-13