Note. Diamox comes in 125 mg tablets too. So, in my case, I take just a half a tablet at a time. Based on my weight and sex, a high altitude specialist recommended 62.5 mg twice a day (although I have now reduced that substantially based on my personal experience). As you will see if you search on "diamox," there is a lot of debate here as to dosage, and whether prophylactic use is appropriate. An issue for you and your doctor....