Isovorin (Calcium Levofolinate)

Isovorin is used in clinical settings where folate pathways are compromised or where antifolate toxicity needs mitigation.

• Rescue therapy after high‑dose methotrexate: reduces methotrexate‑induced toxicity and supports rapid recovery.
• Reduction of methotrexate toxicity: lessens adverse effects during standard methotrexate regimens.
• Folate deficiency: restores normal folate levels in patients with inadequate folate status.
• Supportive care in cancer chemotherapy: enhances DNA synthesis and cell recovery during cytotoxic treatment.

• Calcium Levofolinate supplies a reduced folate that enters cells via the reduced folate carrier, bypassing the dihydrofolate reductase block imposed by antifolate drugs. Inside the cell it is converted to tetrahydrofolate derivatives, which serve as one‑carbon donors for purine and pyrimidine synthesis, thereby restoring DNA replication and mitigating the cytotoxic effects of agents such as methotrexate.

Common Side Effects

• Nausea or vomiting: mild gastrointestinal discomfort that usually resolves without intervention.
• Transient flushing or warmth: brief sensation of heat, often occurring shortly after infusion.
• Mild rash or pruritus: limited skin irritation that does not require treatment.
• Low-grade hypotension: slight drop in blood pressure that is typically self‑limiting.

Serious or Rare Side Effects

• Anaphylactic reaction: severe allergic response requiring immediate medical attention.
• Acute renal impairment: sudden decline in kidney function, especially in patients with pre‑existing renal disease.
• Severe hypotension or shock: marked circulatory collapse that may need emergency support.
• Hemolytic anemia: rapid destruction of red blood cells, presenting with fatigue and jaundice.

Before initiating therapy, consider patient‑specific factors and monitor appropriately.

• Renal impairment: adjust dose and monitor renal function closely.
• Hepatic dysfunction: evaluate liver enzymes and use caution.
• Known folate hypersensitivity: avoid use in patients with documented allergy to folate compounds.
• Pregnancy and lactation: use only if potential benefit outweighs risk, as safety data are limited.
• Concomitant nephrotoxic agents: increase monitoring for renal toxicity.
• Store at ambient temperature: keep in original container, protect from moisture and light.

Potential drug interactions may influence efficacy or safety.

Major Interactions (Avoid)

• Concurrent use of high‑dose folate antagonists (e.g., pemetrexed) may diminish rescue effect.
• Co‑administration with nephrotoxic agents (e.g., cisplatin) can exacerbate renal toxicity.
• Simultaneous use with other folate supplements may lead to excessive folate levels.

Moderate Interactions (Monitor Closely)

• NSAIDs and aspirin: may affect renal clearance, requiring renal function monitoring.
• Penicillins and sulfonamides: possible competition for renal tubular transport.
• Antacids containing aluminum or magnesium: may reduce absorption if oral formulations are used.