fairybasslet:
I don't know. I used EAN 32, (at least that's what I think it was; I'd have to check my log book for sure) in the Flower Gardens and took Sudafed about an hour before every dive.
I also used EAN 32 and Sudafed in Roatan with 4 dives every day for 6 days. In Thailand, I dove air but used Sudafed for my 4 daily dives for 6 days. And here I am...
I guess it does depend upon the person, but if someone has trouble equalizing, like I do, and Sudafed is available, I'd hate to give up diving because of a slight chance of some kind of undefined reaction. Did DAN say what the reactions were?
Drugs on the market are very safe to take. They are tested in extensive clinical trials. However you should be aware that the metabolism and tolerance to drugs among the population varies greatly. This is often due to differences in liver function (and you don't have to have aparent liver dissease for this to be the case).
With this side effects vary greatly. There is no drug that is 100% safe. If you take a drug for some illness, you improve or cure the illness, but there is a risk of course with anything you take. It is also a question of the dose.
A number of drugs may have some unwanted cardiac effects and today all new drugs that reach the market are extensively tested for this.
With older drugs, that have this potential, most people have no problem whatsoever. Probably like you.
But immagine someone who may be susceptible. For some reason, the unwanted effect in this person (and this is very rare) can be much more pronounced. These compounds affect the potassium channel in the heart and may change heart rate or the cardiac excitability. In severe cases and for instance under stress and excercise this can lead to cardiac arrest. This under water is especially bad.
The problem is, that you can't know whether you are sucesptible or not. You will find out when you have such an event. If you are fit, healthy and have taken this drug in teh past, then that is a good sign, but again does not guarrantee anything.
So while diving on sudafed has served you well, and will continue to serve you well, there is an increased risk that you are taking.
When you dive, under increased partial pressures of oxygen, you are now in a grey zone that is no longer covered by clinical trials or any scientific data.
It is a danger of the public to assume that drugs have to be 100% safe and that you can take them at will in any circumstance. At very high doses any drug is toxic (even alcohol! even pure water!). The dose unfortunately varies from person to person and from the circumstance that person is in.
Diving is more risky than taking a sudafed, but the combination again increases risk. It is important to know of the risk before you take it.