WheelerDealer
Guest
I do not know whether or not there have been any studies done on this subject, but I would like to know if there are any drugs, or anything else for that matter, known to increase or decrease ones susceptibility to an oxtox hit.
Can medication increase or decrease oxtox susceptibility??
- Thread starter WheelerDealer
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Many drugs are suspected of increasing the likelyhood of oxtox.
Best is no drugs if possible.
If you need the medication then maybe you should not be doing dives where oxtox is a significant possibility.
Best is no drugs if possible.
If you need the medication then maybe you should not be doing dives where oxtox is a significant possibility.
mwilding
Contributor
according to the PADI manual Sudafed is a nono with Nitrox
RichLockyer
Guest
Why just with nitrox?
There's no difference between EAN32 at 70ft and air at 130ft.
Charlie99
Contributor
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It's a lot more likely that a nitrox diver will have extended exposure to high ppO2. CNS toxicity is a result of both ppO2 and time.
Yes, both 70' on EAN32 and 130' on air are 1.0ata ppO2, but that is both relatively low ppO2 and the air diver isn't going to spend much time at 130'.
The EAN32 diver may spend a lot of time at 111' (ppO2 1.4) or the EAN36 diver at 95' (ppO2=1.4, 40 min NDL) --- while the air diver isn't going to spend much time at 187' -- and PADI doesn't recognize that there is any diving deeper than 130' anyway.
RichLockyer
Guest
That is all true... and while PPO2 and time increase the risk, when a vasoconstrictor such as Sudafed is thrown into the mix, all bets are off. 1.0, or even 0.75, may be high risk for relatively short exposures.
We simply don't know because the only data we have is anecdotal, with one reported tox incident, which hit at the end of the dive, and though the tox hit was at 1.4, apparently, the diver had been in excess of 1.4 for quite a while.
Better safe than sorry... avoid any kind of drug and diving, but so far, Sudafed seems to be relatively safe. I've done many 45 minute 80-100ft dives on EAN32 while using it.
My PADI instructor said that Dramamine was a killer... severely enhancing the effects of narcosis, complete with anecdotal evidence of buddies that knelt at 80ft counting sand grains until they had to be dragged to the surface on the DM's octo...
If that's the case, I think this would be a more serious risk than Sudafed, but we hear very little about seasickness meds.
We simply don't know because the only data we have is anecdotal, with one reported tox incident, which hit at the end of the dive, and though the tox hit was at 1.4, apparently, the diver had been in excess of 1.4 for quite a while.
Better safe than sorry... avoid any kind of drug and diving, but so far, Sudafed seems to be relatively safe. I've done many 45 minute 80-100ft dives on EAN32 while using it.
My PADI instructor said that Dramamine was a killer... severely enhancing the effects of narcosis, complete with anecdotal evidence of buddies that knelt at 80ft counting sand grains until they had to be dragged to the surface on the DM's octo...
If that's the case, I think this would be a more serious risk than Sudafed, but we hear very little about seasickness meds.
The Iceni
Medical Moderator
Hi Wheelerdealer,
The answer to your original question is no. Because the susceptibility to CNS oxygen toxicity is so variable, both between individuals and within the same individual from day to day and at different times of the day, such a a project would not be statistically valid (and I doubt would be ethical to perfiorm.)
The exact mechanism of CNS oxtox is not yet known but unlike pulmonary oxtox it is not a directly accumulative effect but due to the stimulating effects of high partial pressures of oxygen at the level of the tissues of the brain at any time. Theoretically ANY STIMULANT will increase the risk of CNS oxtox and sudafed (pseudoefedrin) is a stimulant closely related to epinefrin.
Some authorities recommend avoiding coffee (caffeine) for the same reason but there is no hard-and-fast evidence either way.
Many divers use sudafed and nasal decongestants without problem and these latter are usually stimulants (xylometazoline being the one most commonly used in the UK.)
Hope that helps,
The answer to your original question is no. Because the susceptibility to CNS oxygen toxicity is so variable, both between individuals and within the same individual from day to day and at different times of the day, such a a project would not be statistically valid (and I doubt would be ethical to perfiorm.)
The exact mechanism of CNS oxtox is not yet known but unlike pulmonary oxtox it is not a directly accumulative effect but due to the stimulating effects of high partial pressures of oxygen at the level of the tissues of the brain at any time. Theoretically ANY STIMULANT will increase the risk of CNS oxtox and sudafed (pseudoefedrin) is a stimulant closely related to epinefrin.
Some authorities recommend avoiding coffee (caffeine) for the same reason but there is no hard-and-fast evidence either way.
Many divers use sudafed and nasal decongestants without problem and these latter are usually stimulants (xylometazoline being the one most commonly used in the UK.)
Hope that helps,
wetvet
Guest
As I understand it, there is some relationship with the oxidising power of oxygen and its free radicals that are involved in Oxtox. To reduce the risk (unquantifiably, to be sure), you can dose yourself with the antioxidant vitamins.....A,C and E. Don't know how much good they will do, but they cant hurt.
Wetvet
Wetvet
BillP
Senior Member
There is laboratory evidence suggesting that caffeine actually reduces the risk of CNS oxygen toxicity- in rats at least.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8574677&dopt=Abstract
Bill
The Iceni
Medical Moderator
yes Bill, and aspirin is poisonous to cats!
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