What factors affect the sufficient dose of methotrexate?

Sufficient dose of methotrexate is affected by many factors, such as a specific condition used for treatment, patient's age and patient size. For example, an adult who uses the drug to treat rheumatoid arthritis requires a drug dose of 7.5 milligrams (mg) per week. A child taking a medicine for the same condition should be administered between 5 and 15 mg of treatment per meter to the second (m ^{2 ) in the size of the body. A sufficient dose of methotrexate for adults taking the medicine for lymphoma, namely Burkitt's tumor in the stages of one or two, is 10 to 25 mg daily for four to eight days.}

The most visible factor that affects enough methotrexate is the condition that the drug treats. For example, if an adult patient is taking a psoriasis medicine, he should be administered between 10 to 25 mg a week until he is responding to treatment. An adult patient taking rheumatoid arthritis requires only 7.5 mg per week. The maximum dose that can be taken in a week is also determined by the condition. For example, patients sufferingPsoriasis can take up to 30 mg per week and patients suffering from rheumatoid arthritis can take up to 20 mg per week.

Elderly patients can generally manage a larger dose of methotrexate than younger patients, so age is an important factor in determining sufficient dose. Anything from 30 mg per m ^{2 in body size up to 40 mg per m 2 per week can be prescribed to an adult using a drug for neoplastic diseases. This can increase dramatically, up to 12,000 mg per m 2 if the medicine is taken with leukovorin. Children can only be prescribed between 7.5 and 30 mg per m 2 and treatment can only be administered every two weeks.}

Methhotrexate is a medicine that can have numerous side effects, and some of them may be maybeatal. For example, the drug can cause death or defects in unborn children, so they should never be used by pregnant women. Other possible fatal side effects include afterPressing bone marrow and lung infection. As a result of these serious possible reactions, the dose of methotrexate should only be increased by a doctor according to the patient's reaction to treatment.

This potential risk associated with treatment means that a dose of methotrexate may need to be changed depending on the size of the patient's body. This is indicated by doses with "per m ^{2 . A simple reason is that larger patients can handle larger doses of treatment and doses that are too large can have negative effects on smaller patients.}