Calcium folinate for injection

Pharmacological action: This product is a formyl derivative of tetrahydrofolate, and is mainly used for the rescue of high-dose methotrexate and other folic acid antagonists. Folic acid is reduced and methylated by dihydrofolate reductase in the small intestinal cells, converted into methyltetrahydrofolate, and then acts as a coenzyme to participate in the synthesis of purine and pyrimidine nucleotides and the conversion of certain amino acids in the body. Methotrexate can bind to dihydrofolate reductase, blocking the conversion of dihydrofolate into tetrahydrofolate, thereby inhibiting the synthesis of thymine nucleotides, DNA, RNA and even proteins. After entering the body, this product is converted into tetrahydrofolate by tetrahydrofolate reductase, which can limit the degree of damage to normal cells caused by methotrexate and reverse the response of methotrexate to the bone marrow and gastrointestinal mucosa, but it has no obvious effect on the neurotoxicity caused by methotrexate that has already occurred.

The main ingredients of this product and its chemical name are: Calcium folinate. Chemical name: 5-methyl-5,6,7,11-tetrahydropteroyl-L-monoglutamic acid calcium salt.

This product is yellow loose mass or powder.

1. Used as an antidote for folic acid antagonists (such as methotrexate, pyrimethoprim or trimethoprim). 2. Used to prevent severe toxic effects caused by overdose or high-dose treatment with methotrexate. 3. Also used to treat megaloblastic anemia caused by folic acid deficiency. 4. Used in combination with 5-fluorouracil for advanced colon and rectal cancer.

1. Calcium folinate "rescue" therapy after folic acid antagonist treatment: The dose of calcium folinate is determined according to the blood concentration of methotrexate. Generally, 24 hours after intravenous injection of methotrexate, this product is used at a dose of 9-15 mg/m2 based on body surface area, once every 6-8 hours for 2 days until the blood methotrexate concentration is below 5×10-8 mol/L. As an antidote for pyrimethamine or trimethoprim, 9 to 15 mg is injected intramuscularly each time, depending on the poisoning situation. 2. Remedy for overdose of methotrexate: When methotrexate is accidentally overdosed, calcium folinate should be used for emergency treatment as promptly as possible; when excretion is delayed, calcium folinate should also be used within 24 hours of methotrexate use. Generally every 6 hours

Rarely, skin rash may occur. Look for allergic reactions such as hives or asthma.

It is contraindicated in pernicious anemia and megaloblastic anemia caused by vitamin B12 deficiency.

Precautions for children: This product should be used with caution in children taking anti-epileptic drugs (see Drug Interactions). Precautions for pregnancy and lactation: Although animal studies have not shown that this product has reproductive toxicity, animal experiments cannot accurately predict human responses. Since calcium folinate has not been properly and adequately controlled clinical studies in pregnant women, this product should not be used during pregnancy unless it is absolutely necessary. It is not clear whether this product is secreted in human milk, and lactating women should use this product with caution. Precautions for the elderly: Studies have shown that the risk of severe gastrointestinal toxicity in elderly patients and/or those with physical weakness increases when this product is used in combination with fluorouracil. Use this product with caution in elderly patients.

Large amounts of folic acid may counteract the anti-epileptic effects of phenobarbital, phenytoin and primidone, increasing the rate of epileptic seizures in some children who are taking anti-epileptic drugs. Preliminary studies in animals and humans have shown that a small amount of folinic acid enters the spinal cord in the form of 5-methylfolate when administered systemically, causing a decrease in the usual blood concentration of methotrexate after intrathecal administration. Therefore, high doses of folinic acid may reduce the effect of intrathecal administration of methotrexate. Folinic acid may increase the toxicity of fluorouracil. This product can be used simultaneously with pyrimethamine or trimethoprim to prevent the latter from causing secondary megaloblastic anemia.

Keep away from light and store in airtight container

100mg(calculated as C20H23N7O7)

24 months