Safety and efficacy of a urine alkalinization protocol developed for high-dose methotrexate patients during intravenous bicarbonate shortage.

Eighteen patients (50% male), median age 65 years, received 76 total high-dose methotrexate cycles. Shortage protocol was used in 37 cycles (48.7%). Mean time to methotrexate clearance did not differ between groups (p = ns). Mean time to urinary alkalinization and duration of hospitalization were not statistically different (p = 0.49 and 0.23, respectively). Average total bicarbonate administered per 24 hours was higher in standard protocol (p < 0.05), but hydration rates were similar (p = 0.73). Creatinine clearance and urine output on days 1 and 2 post-high-dose methotrexate did not significantly differ (creatinine clearance day 1, p = 0.27; creatinine clearance day 2, p = 0.55; urine output day 1, p = 0.62; urine output day 2, p = 0.60). Interruptions in alkalinization were significantly higher during shortage (0.41 ± 0.75 instances of urine pH < 7 during standard vs. 1.3 ± 1.7 under shortage, p < 0.05).