Diving and Diamox

[tridacna]

This is purely a theoretical question. (I am not suggesting its use for SCUBA diving in any way).

I'm curious to get input from others regarding the effects of taking Diamox before diving. Reason for asking is that I'm using it for a Kilimanjaro expedition to prevent Altox and wondered whether it could be of any use in deeper dives. As I understand the mechanism, Acetazolamide forces the kidneys to excrete bicarbonate and ...eventually through increased inspiration/respiration increases the amount of oxygen in the blood.

Besides breathing down your tank faster, would the increase in blood O2 levels have a beneficial effect in diving?

I'm going to Zanzibar immediately after Kilimanjaro to dive. Could there be any residual effect of the Diamox on recreational diving with a <24 hr interval? (That's a real question).

 

[TSandM]

Did you get that information about O2 from the Wikipedia article? If so, you have been somewhat misinformed.

Increasing the volume passing through the lungs in any given time will have minimal effect on the blood oxygen content. The reason for this is that the vast majority of the oxygen is carried on hemoglobin, and hemoglobin, in the healthy person with normal lungs, is 99 to 100% saturated with oxygen when you are breathing normally on room air. You CAN raise the alveolar oxygen concentration a little bit by lowering the CO2, but it's not enough to make a significant difference in dissolved oxygen (even breathing 100% O2 doesn't do that very well).

The primary function of acetazolamide is to hurry the process of acclimatization. Breathing very low O2 levels causes hyperventilation because the hypoxic drive kicks in; this results in alkalinization of the blood, as the CO2 is blown off but the bicarbonate which was buffering it remains. Acetazolamide results in excretion of bicarbonate and faster compensation for the respiratory alkalosis. It also mildly reduces blood volume. I can't think of any way in which it would be beneficial to divers, in that many of us retain a little excess CO2 while diving, and a lower bicarbonate level would make the pH changes as a result of that retention worse. In addition, if volume depletion is a risk factor for DCS, the use of diuretics in general, except where they are medically necessary, should be avoided.

 

[tridacna]

Thank you. And yes, Wiki provided that nugget of misinformation!

More importantly, the answer to question regarding diving after use is...?

 

[DocVikingo]

More importantly, the answer to question regarding diving after use is...?

Long time. What up, tridanca?

Obviously you&#8217;re taking it in the extended-release tablet form, correct?

Acetazolamide is not metabolized; it is excreted unchanged in the urine. The half-life of the tabs is 10-15 hrs; about half of an extended-release dose is eliminated within 24 hrs.

It makes sense to wait at least that long before diving & to make a massive effort to hydrate once the drug is discontinued. Remember, you're also going to be taking a dehydrating plane flight & the temps in Zanzibar can run high in the warm season.

Best of luck & do enjoy that envy-provoking trip.

DocV

This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.

 

[Agility]

not directly related to acetazolamide but would an acclimatization to such extreme heights not increase haemoglobin levels and therefore (slightly) increase the risk of thrombosis especially on the flight?

 

[tridacna]

Obviously you’re taking it in the extended-release tablet form, correct?

YES

It makes sense to wait at least that long before diving & to make a massive effort to hydrate once the drug is discontinued. Remember, you're also going to be taking a dehydrating plane flight & the temps in Zanzibar can run high in the warm season.

I will do so. I'll "force" myself to drink! Should be a great trip. 4 days in Serengeti; 7 days up Kili; 4 days diving in Zanzibar. Life could be worse!

Cheers!

 

[TSandM]

Red cells are pretty slippery. I'm not aware of any increase in thrombotic events occurring in people living at altitude. You can get them in people with pathologic conditions that REALLY raise red cell numbers (polycythemia Vera) but altitude doesn't get the hematocrit to those levels.

 

[gkwalt]

I know that certain athletics use EPOgen to increase their RBC count to increase their oxygenation. There is a certain acclimatization that exist when people live at altitude, however this is to compensate for the relative hypoxia. But its the platelets that cause clotting. There would need to be a significant increase in red blood cell count (hematocrit) to account for clotting.