Leucovorin Pfizer (Calcium Folinate Pentahydrate)

Leucovorin Pfizer (calcium folinate) is used in oncology and hematology to mitigate folate pathway inhibition caused by certain chemotherapeutic agents.

• High‑dose methotrexate rescue: restores folate pools to reduce methotrexate‑induced organ toxicity.
• 5‑Fluorouracil toxicity reduction: lessens mucosal and hematologic side effects during 5‑FU‑based regimens.
• Folate deficiency treatment: corrects low serum folate levels in patients with malabsorption or increased demand.
• Chemotherapy adjunct: enhances efficacy and tolerability of selected antifolate chemotherapy protocols.

• Calcium folinate provides a reduced form of folic acid that enters the intracellular folate cycle downstream of dihydrofolate reductase. By bypassing the DHFR blockade created by antifolate drugs, it replenishes tetrahydrofolate cofactors required for purine and pyrimidine synthesis, thereby supporting DNA replication and repair while diminishing the cytotoxic impact of agents such as methotrexate and 5‑fluorouracil. This metabolic rescue helps maintain normal cell proliferation in healthy tissues during chemotherapy.

Calcium folinate may be associated with a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Nausea or vomiting: mild upset that resolves spontaneously.
• Mild skin rash or itching: transient erythema without lasting effects.
• Transient elevation of liver enzymes: temporary ALT/AST rise returning to baseline.
• Low‑grade fever: temperature up to 38°C, self‑limiting.
• Headache: dull pain improving with standard analgesics.
• Injection site discomfort: pain, redness, or swelling locally.

Serious or Rare Side Effects

• Severe allergic reaction (anaphylaxis): breathing difficulty, swelling, hypotension needing emergency care.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis: extensive skin detachment, medical emergency.
• Acute renal impairment: sudden rise in creatinine indicating kidney injury.
• Severe neutropenia or thrombocytopenia: marked drop in blood cells increasing infection risk.
• Cardiac arrhythmia: irregular heart rhythm that may require monitoring.
• Hypotension requiring medical intervention: significant blood pressure drop needing treatment.

When using Leucovorin Pfizer, several precautionary measures should be observed to ensure safety and effectiveness.

• Renal function monitoring: assess creatinine clearance before and during therapy.
• Hepatic function monitoring: check liver enzymes periodically.
• Hypersensitivity assessment: discontinue if signs of allergic reaction appear.
• Dose adjustment in renal impairment: reduce dose according to renal function.
• Concomitant antifolate agents: avoid simultaneous use that may increase toxicity.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze.

Calcium folinate can interact with other medicines; awareness of major and moderate interactions helps prevent adverse outcomes.

Major Interactions (Avoid)

• High‑dose methotrexate given concurrently: may reduce rescue effectiveness.
• Pemetrexed or other antifolates: can increase toxicity if not timed correctly.
• Live bacterial vaccines: folinic acid may diminish vaccine efficacy.

Moderate Interactions (Monitor Closely)

• NSAIDs: may affect renal clearance of calcium folinate.
• Penicillins (e.g., ampicillin): can interfere with folate metabolism.
• Phenytoin: may reduce folate levels.
• Sulfonamides: potential additive effect on bone marrow suppression.