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All price changes →Indications & Uses
Folistar is used to counteract the immediate toxic effects of folic acid antagonists such as methotrexate, and is central to calcium folinate rescue, a treatment technique in which calcium folinate is given alongside folic acid antagonists like methotrexate to minimise systemic toxicity. It is also used to treat megaloblastic anaemias arising from sprue, nutritional deficiency, pregnancy, infancy, liver disease and malabsorption syndrome.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
Folinic Acid rescue should begin as soon as possible after an inadvertent overdose and within 24 hours of methotrexate administration when there is delayed excretion. There are no fixed guidelines regarding the dose of methotrexate that triggers an automatic subsequent Folinic Acid administration, since tolerance to this folate antagonist depends on various factors. The dose of methotrexate varies, but folinate rescue is necessary when methotrexate is given at doses exceeding 500 mg/m2 and should be considered at doses of 100 mg to 500 mg/m2. Folinic Acid rescue treatment should commence approximately 24 hours after the start of the methotrexate infusion. Dosage regimens vary depending on the dose of methotrexate given. In general, Folinic Acid should be given at a dose of 15 mg (approximately 10 mg/m2) every 6 hours for 10 doses. The recommended dose of Folinic Acid to counter hematologic toxicity from folic acid antagonists with less affinity for mammalian dihydrofolate reductase than methotrexate, such as trimethoprim and pyrimethamine, is substantially lower, and 5 mg to 15 mg of Folinic Acid per day has been recommended. Neutralising the immediate toxic effects of folic acid antagonists: if overdose of methotrexate is suspected, the dose of Folinic Acid should be equal to or greater than the dose of methotrexate and should be given within one hour of the methotrexate administration. Megaloblastic anaemia (folate deficiency): 5 mg to 15 mg of Folinic Acid per day. Use in children and adolescents: the safety and efficacy of folinic acid in children and adolescents have not been established.
Side Effects
Common side effects of Folistar include mucositis, stomatitis, leukopenia and/or diarrhea, which can limit the dose used.
Cautions & Contraindications
Warnings & Precautions
Folistar should only be used together with methotrexate or 5-FU under the direct supervision of a clinician who is experienced in the use of cancer chemotherapeutic agents. When treating inadvertent overdosage of a folic acid antagonist, folinate should be given as soon as possible, since if more than 4 hours pass before treatment begins, it may no longer be effective. In general, Folistar should not be given at the same time as folic acid antagonists such as methotrexate to abort clinical toxicity, because doing so may nullify the therapeutic effect of the antagonist. However, when Folistar is given concurrently with folate antagonists such as pyrimethamine and trimethoprim, it does not inhibit their antibacterial activity. Ensuring the prompt excretion of methotrexate is an important part of Folistar Rescue Therapy. This involves alkalinising the urine so that the urinary pH is greater than 7.0 before the methotrexate infusion, which increases the solubility of methotrexate and its metabolites, and maintaining a urine output of 1800 to 2000 cc/m2 every 24 hours through increased oral or intravenous fluids on days 2, 3 and 4 following methotrexate therapy. Plasma methotrexate concentration, BUN and creatinine should be measured on days 2, 3 and 4, and these measures should continue until the plasma methotrexate level falls below 10 to the power of minus 7 molar.
Contraindications
Folinic Acid should not be used by anyone with a known hypersensitivity to calcium folinate or to any other ingredient in this product. It is also unsuitable for pernicious anaemia or other forms of megaloblastic anaemia caused by vitamin B12 deficiency. Patients with rare hereditary conditions such as galactose intolerance, lapp lactase deficiency, or glucose-galactose malabsorption should avoid calcium folinate tablets.