Folinic Acid Overview

Continuing Education Activity

• Folinic Acid (Leucovorin): Used in cancer treatment with 5-fluorouracil (5-FU) and as an antidote for methotrexate.
• Functions: Antidote, chemotherapy modulator, rescue agent.
• Focus Areas: Indications, mechanisms, contraindications, cancer treatment, anemia, adverse effects, monitoring, interprofessional care.

Objectives

• Identify clinical indications for folinic acid.
• Implement therapy per guidelines.
• Manage adverse effects and interactions.
• Communicate effectively with patients and caregivers.

Indications

• Folinic Acid vs Folic Acid: Folinic acid is naturally occurring and biologically active, while folic acid is synthetic and oxidized.

• FDA-Approved Uses:

  • Enhances 5-FU effects for cancers, especially colorectal.
  • Antidote for high-dose methotrexate effects.
  • Treats megaloblastic anemia.

• Off-Label Uses:

  • Breast cancer (5-FU potentiation).
  • Other cancers: gallbladder, biliary tree, gastric, head and neck, pancreatic.
  • Non-Hodgkin lymphomas.
  • Toxoplasmosis and pneumonia prophylaxis.
  • Reduces plasma homocysteine levels.
  • Prevents bone marrow suppression from nitrous oxide.

Mechanism of Action

• Folinic acid bypasses dihydrofolate reductase.
• Participates in DNA synthesis and repair by stabilizing inhibitory complexes.
• Key roles: Counteracts folic acid antagonists and enhances fluoropyrimidines.

Pharmacokinetics

• Absorption: Rapid, dose-dependent.
• Distribution: Greater with IV than oral.
• Metabolism: Occurs in liver/GI, 6-hour half-life.
• Elimination: Mostly urinary.

Administration

• Forms: Tablets (5-25 mg), injectable (10-20 mg/mL).
• Dosing:
  • High-dose methotrexate rescue: Various routes every 6 hours.
  • Colorectal cancer with 5-FU: IV dosing cycles.
  • Pediatric dosing parallels adult dosing.

Special Populations

• Hepatic/Renal Impairment: Dosing undefined.
• Pregnancy/Breastfeeding: Generally safe.
• Older Patients: No specific contraindications.

Adverse Effects

• Common: GI upset, leukopenia, stomatitis, rash.
• Severe: Anaphylactic reactions, hypocalcemia.
• Monitoring of calcium and GI adverse effects is recommended.

Drug Interactions

• Avoid with capecitabine, pafolacianine, sulfamethoxazole, trimethoprim.

Contraindications

• GI toxicity with 5-FU, intrathecal use, hypersensitivity to components.

Monitoring

• Hematologic improvements as efficacy indicators.
• Serum creatinine and methotrexate levels for methotrexate toxicity.

Toxicity

• Overdose is rare, effects similar to adverse effects.
• Excessive dosing may nullify chemotherapy benefits.

Healthcare Team Outcomes

• Role of interprofessional team critical in monitoring and managing therapy.
• Close coordination and communication among team members essential.

References

• Extensive studies and ongoing research emphasize updated patient care approaches.

These notes summarize the key points regarding folinic acid, its uses, mechanisms, and considerations in clinical practice, providing a comprehensive overview for healthcare providers involved in related treatments.