Abstract
An important step in preventing methotrexate (MTX) toxicity is to assess patient self-medication of over-the-counter drugs before high-dose methotrexate (HDMTX) treatment is administered. Nonsteroidal anti-inflammatory drugs given within a 10-day period before a patient receives HDMTX leads to a decreased MTX excretion rate causing MTX toxicity. Education of the nursing staff and patients and their families is vital to avoid the potentially dangerous effects of a delayed MTX excretion rate.