Hey Tom and all,
Actually, I was specifically trying to avoid brand names, lest there be any legal issues raised. However, Pseudoephedrine, the active ingredient in the aforementioned product, is a CNS (Central Nervous System) exciter and would predispose you to Oxygen toxicity. We are very careful to plan our dives to stay within a PPO2 of 1.4 ata, with a PPO2 of 1.6 ata as the maximum contingency. Much more than that can bring on sudden convulsions with absolutely no warning. Obviously, underwater these convulsions usually result in drowning. So if I take a drug that makes me far more susceptible to OxTox, then the actual PPO2 that can kill me changes. Way unfortunately, I have no way to quantify this and make the proper adjustments in my diving profile. Thus I would be diving blind in regards to my Oxygen exposure, and hoping that I guessed it right. See page 39 of the PADI Enriched Air Diver Manual for a far better analysis of the situation.
The actual problem lies in the way the cells metabolize Oxygen. Thats why we dont have to worry about having too much of it in us when we ascend
our cells consume it quite quickly. However, when the PPO2 gets too high the cells are overwhelmed and the oxygen actually disrupts normal cell behavior. Nitrogen, on the other hand is NOT metabolized and so we have to worry about how we are going to off-gas the excess. It also has a narcotic effect that can be affected by drugs that alter our CNS. As with oxygen, there is no way to quantify the effects it has on our ability to withstand its narcotic effects or how our cells will be able to off-gas it on ascent.
There are just too many variables and not enough facts! There are more questions raised than answered. I stopped using the pills and had my doctor prescribe a steroidal spray. The amount of the steroid absorbed is so insignificant that according to my Doctor, it is safe to dive with! Oh yeah, ingested steroids are CNS exciters too!!!
:nono:
To answer your question directly: there is no data on what PPO2 or EAD (Equivalent Air Depth) that Pseudoephedrine (or any drug) becomes a problem. Its your guess AND your life... choose wisely!
Hope this helps, and is not too wordy...