One remarkable finding in this week's acetazolamide article is the modest decrease in bicarbonate especially given the high doses used.
In our NehJC article by Faisy article, the authors found a reduction of only 0.8 mmol/L with 500-1,000 mg of acetazolamide twice a day.
Moviat, et al. found a reduction of 3 mmol/L with a single dose of 500 mg of acetazolamide. Patients needed to have a bicarbonate of 28 to be enrolled.
Marik, et al. found an even larger drop of 6.4 mmol/L with a single dose of 500 mg of acetazolamide. Patients needed to have a serum bicarbonate of 30 mmol/L to be enrolled.
Mazur et al randomized patients to either a single dose of 500 mg or 250 mg q6h. Though they did not find a difference between the effectiveness of the two dosing strategies they did find a drop in serum bicarbonate of 6 mmol/L. Patients had to have a bicarbonate of at least 26 and a pH ≥ 7.48.
This week's NephJC article isn't Faisy's first time on the acetazolamide merry-go-round, he published a similar study in 2010 that largely supported the results of this article. In the 2010 article the bicarbonate fell by...I have no idea. OPEN ACCESS NOW! (or at least include the data I'm looking for in your abstract).
In a retrospective study of 69 patients with COPD, mean serum bicarbonate of 37.5, the pharmacists found a nice dose response curve to acetazolamide:
This is my primary concern about this study of acetazolamide, they didn't see much of an effect. In fact, the effect they did see was dramatically less than has been recorded in other studies.
See you tonight and tomorrow.