Pfizer Leucovorin Injection 15mg (Calcium Leucovorin)

Adult dosage

1. Standard methotrexate therapy: Administer 6-12mg of leucovorin intramuscularly every 6 hours for a total of 4 doses per day in case of adverse reactions to methotrexate. Additionally, administer an equivalent dose in case of methotrexate overdose. 2. Methotrexate-leucovorin rescue therapy: Administer leucovorin 15mg intravenously every 3 hours for 9 doses starting 3 hours after discontinuation of methotrexate, then administer every 6 hours for 8 doses or intramuscularly.

This medication is not suitable for treating pernicious anemia or megaloblastic anemia caused by vitamin B12 deficiency. Neurological symptoms may improve even if hematological status remains compromised, so caution is needed. In the case of injectable forms, be very careful when opening the ampoule as glass fragments may enter, especially when used in children or the elderly. Pregnant or breastfeeding women should not use this drug in conjunction with 5-FU, and caution should be exercised even when administered alone. This drug may cause allergic reactions such as urticaria or anaphylaxis, so any unusual symptoms must be reported to medical personnel immediately. Pain or temporary discomfort may occur at the injection site, and rarely fever or central nervous system symptoms (paralysis, agitation, depression) may appear. When administered with 5-FU, side effects such as diarrhea, skin reactions, or mucositis may occur, necessitating dosage adjustments of 5-FU based on symptoms. This drug should be used in conjunction with methotrexate, and the plasma concentration of methotrexate should be regularly monitored to assess treatment efficacy and toxicity reduction. In cases of renal impairment or excessive fluid retention, drug excretion may be delayed, and dosage adjustments may be required. This medication uses a transporter similar to methotrexate, so patients resistant to methotrexate may also be resistant to this drug. In cases of vomiting or difficulty absorbing orally, it is preferable to administer this drug intravenously rather than orally. In patients with central nervous system tumors, repeated administration may lead to drug accumulation, diminishing anticancer effects, so avoid overdose. This medication is not used for the treatment of macrocytic anemia caused by specific DNA synthesis inhibitors. Additionally, this drug may increase the metabolism of enzymes in the liver, potentially lowering serum concentrations of some anticonvulsants, thus monitoring plasma concentration and dosage adjustments are necessary in pediatric patients at risk for seizures. It may increase the efficacy and side effects of 5-FU, so caution is necessary when co-administering. Pregnant and breastfeeding women should administer this drug considering the established safety for fetuses and newborns, weighing the needs against the risks. Elderly individuals may have an increased risk of side effects due to diminished bodily functions and should be monitored carefully. This medication is contraindicated for epidural administration, and caution should be taken not to inject too quickly due to its calcium content during intravenous administration. Store out of reach of children and keep in its original container to prevent misuse or degradation of quality.

Serious side effects

Urticaria → Severe allergic reaction

Mild side effects

Vein pain at the injection site, transient discomfort, fever, central nervous system disturbances (paralytic disorders, agitation, depression), diarrhea, skin reactions, dry skin, mucositis, conjunctivitis, mild blood toxicity, leukopenia, urticaria

This medication should be stored in a sealed container to avoid contact with air and kept in a cool place between 2 and 8 degrees Celsius. It is also important to avoid direct sunlight, as light may degrade its efficacy.

Appearance

A clear yellow injection solution filled in a brown ampoule

Package unit

2 milliliters X 5 ampoules