Adults

For severe folate deficiency or specific conditions, dosage typically ranges from 5-15 mg orally once daily, or as directed by a physician. Doses up to 25 mg daily may be used in certain severe cases like profound malabsorption.

Elderly

Similar to adult dosage; caution and monitoring are advised, especially with renal impairment. Adjustments may be made based on individual needs and renal function.

Pediatric

For children, due to the high strength, Foli-Kidz 25 mg oral solution should be used strictly as directed by a specialist physician for specific severe conditions (e.g., severe megaloblastic anemia, certain chronic hemolytic conditions, or drug-induced folate antagonism) and not for routine supplementation.

Renal_impairment

No specific dose reduction is typically required for renal impairment, but monitoring of folate levels is recommended. Patients on dialysis may require higher doses due to increased folate loss.

Onset

Biochemical effects are generally observed within hours to days, with hematological improvement visible over several days to weeks, depending on the severity of deficiency.

Excretion

Excess folic acid is excreted unchanged in the urine, particularly at higher doses. Metabolites are also excreted renally. Enterohepatic recirculation also occurs.

Half life

The plasma half-life of unmetabolized folic acid is approximately 30 minutes to a few hours. However, active folate forms have a longer physiological half-life within cells.

Absorption

Folic acid is readily and extensively absorbed primarily from the proximal small intestine. Absorption is nearly complete for doses up to 20 mg. Peak plasma concentrations are reached within 1 hour after oral administration.

Metabolism

Folic acid is extensively metabolized in the liver and intestinal mucosa to its active coenzyme forms, mainly tetrahydrofolate and 5-methyltetrahydrofolate.

Methotrexate

Folic acid can reduce the toxicity of methotrexate, especially in high-dose therapy, but should be carefully managed as it may reduce the anticancer effect.

Trimethoprim

A folate antagonist, concurrent use may increase folate deficiency, especially in patients with pre-existing low folate stores.

Sulfasalazine

This drug can inhibit the absorption and metabolism of folic acid.

Antiepileptic drugs (e.g., phenytoin, phenobarbital, primidone)

Folic acid may decrease the plasma concentration of these drugs, potentially leading to increased seizure frequency. Close monitoring and dose adjustments may be necessary.