What precaution is suggested for the administration of methotrexate in relation to urine?

The suggestion to keep urine alkaline during the administration of methotrexate is based on the properties of the drug and its excretion. Methotrexate is a chemotherapy agent that can be toxic, particularly at high doses, and it is eliminated from the body primarily through the kidneys. If the urine is more acidic, the solubility of methotrexate in the urine decreases, which can lead to precipitation of the drug in the renal tubules and increase the risk of nephrotoxicity.

Maintaining an alkaline urine can help to increase the solubility of methotrexate, facilitating its excretion and reducing the chances of adverse effects related to kidney function. Furthermore, an alkaline environment can assist in preventing the formation of crystals, thereby protecting the renal system from possible damage caused by crystal deposits.

This understanding of urine pH's role in the excretion of methotrexate is crucial in managing patients receiving this treatment, as it ensures that the drug is effectively cleared from the body while minimizing potential side effects associated with its accumulation.