This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Maintenance of high urinary pH is impoant during methotrexate treatment because 
Select and explain. 
A. Bladder irritation is reduced, B. It decreases renal tubular secretion of methotrexate, C. Leucovorin toxicity is increased in a dehydrated patient, D. Methotrexate is a weak acid
D: Methotrexate is a weak acid
Answer: D: Methotrexate is a weak acid 
Explanation: Ref-KDT 6/e p823 Methotrexate is a weak acid and basic reabsorbed in acids urinary PH. Higher plasma concentration may result in toxicity. Therefore to decrease the reabsorptiion through renal tubes urinary pH must be maintained