norcalhiker67,

Caveat: Not a doctor.

While your Rx may have been for 500mg 2x day (the full Rx'd dose), see the following informative discussion on Diamox and dosages on the other board. Ken (referred to at the beginning of the thread) is a doctor, if memory serves.

From my reading of numerous posts on this topic over the years on both boards, it has been my observation that, more often than not, 125mg 2x day, or even 62.5mg 2x day (depending on body weight) can be effective for dealing with altitude issues, and with fewer (or even no) side effects, when compared to taking the full Rx'd dose. Also, people who do take it, usually begin taking it a day or two ahead of time to get it in their system.

CaT

If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)