Folic acid

Oral
Prophylaxis of neural tube defect in pregnancy

Oral
Folate-deficient megaloblastic anaemia

Parenteral
Folate-deficient megaloblastic anaemia

May be taken with or without food.

Untreated pernicious anaemia, untreated cobalamin deficiency or other cause of cobalamin deficiency.

Patients with folate-dependent tumours.

Cardiac disorders: Flushing.
Gastrointestinal disorders: Anorexia, nausea, abdominal distention, flatulence.
Immune system disorders: Allergic reactions.
Nervous system disorders: Malaise.
Respiratory, thoracic and mediastinal disorders: Bronchospasm.
Skin and subcutaneous tissue disorders: Erythema, pruritus, skin rash, hypersensitivity.

PO: A

Perform cobalamin absorption test for elderly prior to initiation of therapy.

May decrease concentration of phenytoin. Decreased absorption with sulfasalazine and triamterene. Chloramphenicol, methotrexate and co-trimoxazole may interfere with folate metabolism. May enhance efficacy of lithium.

Description: Folic acid is essential for the production of coenzymes in many metabolic systems such as purine and pyrimidine synthesis. It is also essential in nucleoprotein synthesis, maintenance of erythropoiesis and stimulation of WBC and platelet production in folate-deficiency anaemia.
Onset: 0.5-1 hour (oral).
Pharmacokinetics:
Absorption: Rapidly absorbed from the proximal part of small intestine. Bioavailability: Approx 100% (folic acid supplement); 85% (with food); 50% (dietary folate). Time to peak plasma concentration: 1 hour (oral).
Distribution: Distributed to body tissues and stored in the liver. Actively concentrated in the CSF, and enters breast milk. Extensively bound to plasma protein.
Metabolism: Metabolised in the liver and plasma to active metabolite, 5- methyltetrahydrofolate. Undegoes enterohepatic circulation.
Excretion: Via urine.

Source: National Center for Biotechnology Information. PubChem Database. Folic acid, CID=135398658, https://pubchem.ncbi.nlm.nih.gov/compound/Folic-acid (accessed on Jan. 21, 2020)

Store between 20-25°C. Protect from light.

Vitamins & Minerals (Pre & Post Natal) / Antianemics

B03BB01 - folic acid ; Belongs to the class of folic acid and derivatives. Used in the treatment of anemia.

Anon. Folic Acid. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 25/01/2019.

Anon. Folic Acid. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 24/01/2019.

Buckingham R (ed). Folic Acid. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 24/01/2019.

Folic Acid Injection, Solution (Fresenius Kabi USA, LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 25/01/2019.

Joint Formulary Committee. Folic Acid. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 24/01/2019.