Calcium folinate

Oral
Antidote for methotrexate toxicity
Adult: 15 mg every 6 hr for 10 doses starting 24 hr after the start of methotrexate infusion. Continue admin until serum levels of methotrexate is <0.05 micromolar. May also be given via IM/IV inj.

Oral
Folate-deficient megaloblastic anaemia
Adult: 15 mg daily.

Intravenous
Adjunct to fluorouracil in colorectal cancer
Adult: 200 mg/m² BSA by slow IV inj over at least 3 min followed by 370 mg/m² fluorouracil by IV inj. Treatment is given for 5 consecutive days and repeated at intervals of 28 days for 2 courses. Subsequently, may repeat at 4-5 wkly intervals if the patient has recovered completely from the toxic effects of the prior treatment course.
Incompatibility: Incompatible with fluorouracil when mixed in various ratios and stored in PVC containers at various temperatures.

Intramuscular
Folate-deficient megaloblastic anaemia
Adult: Up to 1 mg/day.
Incompatibility: Incompatible with fluorouracil when mixed in various ratios and stored in PVC containers at various temperatures.

Hypersensitivity, pernicious anaemia and other megaloblastic anaemias secondary to vit B₁₂-deficiency, intrathecal and intraventricular admin.

Undiagnosed megaloblastic anaemia, folate dependent tumors; pregnancy. Monitor calcium levels in patients receiving combined 5-Fluorouracil/Folinic acid treatment. To be given parenterally in the presence of GI toxicity, nausea or vomiting. Monitor serum levels of methotrexate to determine the optimal dose and duration of folinic acid admin. Monitor CBC, electrolytes and liver function tests before and regularly during treatment.

Allergic sensitisation, rash, pruritus, eythema, urticaria, nausea, vomiting, pyrexia.

Reduces methotrexate toxicity. Enhances cytotoxic and anti-neoplastic effects of fluorouracil. Increases risk of seizures in epileptic patients treated with primidone, phenytoin, phenobarbital and succinimides.

Calcium folinate enters the cells as 5-methyl tetrahydrofolate and supplies the cofactor blocked by methotrexate. It stabilises the binding of 5-dUMP and thrymidylate synthetase, enhances flourouracil activity and neutralises the effects of folic acid antagonists such as methotrexate but increases those of 5-fluorouracil.
Absorption: Well absorbed (oral, IM).
Distribution: Widely distributed; concentrated in the liver and CSF.
Metabolism: Hepatic, intestinal; converted to biologically active 5-methyltetrahydrofolate.
Excretion: Urine, faeces (small amounts).

Intramuscular: Store at 15-30°C. Intravenous: Store at 15-30°C. Oral: Store at 15-30°C.

Antidotes, Detoxifying Agents & Drugs Used in Substance Dependence / Supportive Care Therapy / Vitamins & Minerals (Pre & Post Natal) / Antianemics