Isovorin

Health and Nutrition > Medicines > I



How does it work?

Isovorin injection contains the active ingredient calcium levofolinate, also known as calcium levoleucovorin. This is the calcium salt of a vitamin called levofolinic acid, which is related to folic acid. It is usually referred to simply as folinic acid. Folinic acid is a vitamin that has various uses. It is used to reduce the side effects from high doses of the anticancer medicine methotrexate. It is also used in combination with the anticancer medicine fluorouracil (5-FU), as it has been shown to boost the response rate to this anticancer medicine. In cancer treatment with the chemotherapy medicine methotrexate, folinic acid is given for 'folinic acid rescue therapy'. It helps healthy cells recover from the effects of the methotrexate. Methotrexate works by blocking the action of an enzyme in the body called dihydrofolate reductase. Cancer cells in the body use this enzyme to convert folic acid consumed in the diet into tetrahydrofolic acid. They then use tetrahydrofolic acid to make new genetic material, which allows the cancer cells to grow and multiply. However, healthy body cells also use this enzyme to make tetrahydrofolic acid. So while methotrexate can stop cancer cells from producing tetrahydrofolic acid to grow and multiply, it also has the same effect in healthy body cells. This is what causes the side effects of the chemotherapy, for example, decreased numbers of white blood cells. Folinic acid is a derivative of tetrahydrofolic acid and is usually given 24 hours after the methotrexate. It doesn't need to be converted by dihydrofolate reductase to be used by the body cells, so it bypasses the action of the methotrexate and allows the cells to grow and multiply again. Normal healthy cells recover faster than cancer cells and this helps to prevent the side effects of the methotrexate. The aim is to progressively shrink the cancer over several cycles of chemotherapy, allowing normal healthy cells to recover in between. Fluorouracil (5-FU) is a chemotherapy medicine that works in a different way to methotrexate. It reacts with tetrahydrofolate inside cells and forms a complex that is harmful to the cells. Folinic acid is used in combination with 5-FU to increase the amount of tetrahydrofolate inside the cells and therefore boost the effect of the 5-FU. It has been shown to boost the effectiveness of 5-FU in the treatment of advanced colorectal cancer. The injection is given directly into a muscle or a vein, or is diluted and given as a drip into a vein (intravenous infusion).

What is it used for?