Precautions and monitoring required for patients taking MTX
Monitoring: before starting MTX, CBC with platelets, hepatitis B and C serologies, aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, and creatinine (CrCl) should be obtained. A chest x-ray should be performed if the patient has not had one in the past year. Monitor CBC, creatinine, and liver transaminases every 2 to 4 weeks for the first 3 months, then every 8 to 12 weeks for the next 3 to 6 months, and then every 12 weeks.
Precautions: MTX should not be used in patients on dialysis or who have a CrCl <30 mL/minute. The dose should be reduced by 25% and 50% for CrCl <80 mL/minute and <50 mL/minute, respectively. Patients should also avoid or limit (less than three to five drinks per week) alcohol (hepatoxicity) and trimethoprim–sulfamethoxazole (decreases excretion).
MTX is contraindicated in pregnancy, and female patients of child-bearing age should use a reliable form of contraception. MTX should be stopped for 3 months in both men and women before attempting to get pregnant since the normal life cycle from oocyte to mature egg is 90 days. MTX can accumulate in pleural effusions and be reabsorbed causing neutropenia. MTX should not be used without consultation with a hepatologist in patients with hepatitis B or C infections.