No scientific evidence that Sudafed, Zyban or ....

[DocVikingo]

.... acetaminophen contribute to oxtox.

Within the context of this 11-06-02 thread on Sudafed http://www.scubaboard.com/showthread.php?s=&threadid=17351&highlight=zyban , "tinman" indicated that at a recent Great Lakes Chapter Undersea and Hyperbaric Medical Society meeting Dr. Debbie Pestell, Military MD consultant in Diving and Hyperbaric Medicine at DRDC Toronto, presented a paper on CNS Oxygen Toxicity. She reported on the fact that "Sudafed, Acetaminophin (Tylenol et al), and Zyban (a stop smoking med.) can contribute to the onset of oxygen toxicity."

I expressed skepticism that scientific studies had investigated this, and indicated that I'd be looking closely into these assertions.

Dr. Pestell & I have since exchanged several e-mails, and she has stated that, "I wish I had supportive literature to send on to you! The cold hard facts of the matter are this: medications were not developed by drug companies with divers in mind, just as they were not developed with pregnant women in mind. There are no studies out there!"

That Sudafed can contribute to oxtox remains entirely a theoretical position.

Best regards.

DocVikingo

 

[BillP]

Thanks for the followup, DocV!

Yes, there is the theoretical concern that a central nervous system (CNS) stimulant like pseudoephedrine (eg Sudafed) might increase the risk of oxygen toxicity in divers, but theories don't always hold when put to the test.

For example, caffeine is also a CNS stimulant and theoretically it also should increase the risk of oxygen toxicity. But the only experimental evidence that I'm aware of indicates that caffeine significantly reduces the risk of oxygen toxicity (in rats, at least).

Reasonable caution with the use of CNS stimulants is advisable, but not paranoia, IMHO.

Regarding pseudoephedrine and diving, DAN recommends:

"In normal, healthy divers breathing air, occasional use of pseudoephedrine at the recommended dose is probably safe. This presumes that the drug has been taken during periods when no diving has occurred and that no undesirable reactions have occurred. However, one should avoid chronic (daily) use when diving, and it seems reasonable to avoid the drug entirely if diving while using oxygen-nitrogen mixes where the PO2 during a dive might exceed 1.4 ata, the current recommended "safe" open-circuit scuba limit."

That recommendation is very conservative, again IMO.

Just my 2¢,

Bill

The above information is intended for discussion purposes only and is not meant as specific medical advice for any individual.

 

[The Chairman]

Hmnnn, that's the magic number already, ain't it? Other than 1.6 ata being the "contingency" pressure. They might have well said you should avoid drinking water before a dive that might exceed 1.4 ata, or did I miss something here?

 

[DocVikingo]

As BillP suggested, the DAN position here appears very conservative.

IMHO, their positions on many medical issues are very conservative.

Still, given that many of them are best guesses in the absence solid science, one can appreciate their legal & ethical concerns.

Shame there's not more funding for investigating topics such as this one. It could be quite valuable, not to mention exciting, to explore them.

Best regards.

DocVikingo

 

[Norda]

With all these posts I haven't seen any mention of Afrin (Oxymetozoline Hydrochloride). While only recently certified, I have used it on every dive at the recommendation of both my ENT and LDS. For me it is more effective and quicker at relieving ear related congestion with no ill effects yet.

 

[BillP]

Howdy Norda:

I'm not quite sure that I understand the point of your post in this thread on oxygen toxicity, so please forgive me if I miss the mark.

Oxymetazoline is a fine long lasting topical nasal decongestant. It is the preferred decongestant for some hyperbaric specialists because it is topical and primarily has a local rather than much of a systemic action. It is in the same family of drugs as pseudoephedrine, but since it's topical it should not increase the risk of CNS oxygen toxicity significantly in normal doses in most people. I'm glad that it works for you.

However, its use is somewhat controversial. We're back to the point that in theory oxymetazoline should help with congestion, but the problem is, it is topical and only really works where it's applied. In practice if it doesn't get to the eustachain tube it won't help the ears clear. In the few studies that have looked at oxymetazoline and clearing, it seems little if any better than placebo.

See:

http://www.ncbi.nlm.nih.gov:80/entr...eve&db=PubMed&list_uids=9596428&dopt=Abstract

and

http://www.ncbi.nlm.nih.gov:80/entr...eve&db=PubMed&list_uids=1443845&dopt=Abstract

and

http://www.ncbi.nlm.nih.gov:80/entr...eve&db=PubMed&list_uids=8906761&dopt=Abstract

The other concern about oxymetazoline is that it has a significant rebound if used for more than just a few days. For a single day's diving, it might help, but for a long trip with multiple days diving it might do more harm than good in some people.

HTH,

Bill

The above information is intended for discussion purposes only and is not meant as specific medical advice for any individual.

 

[The Chairman]

steroidal sprays like Nasal-Crom??? Which seem to be designed for long term applications?

 

[BillP]

NetDoc asked...
So, would this would be in contrast to steroidal sprays like Nasal-Crom??? Which seem to be designed for long term applications?

First, NasalCrom isn't a steroidal spray. It is Cromolyn Sodium which is a chemical that stabilizes mast cells. Mast cells are cells that release that nasty histamine that causes some people so many problems.

Second, I think I'd say in some ways it's more in comparison to rather than "in contrast to". Like oxymetazoline, NasalCrom is topical and if it doesn't reach the area of interest, it doesn't help. It can work wonders for some people where you apply it. It doesn't work immediately like oxymetazoline and can take days to start to have an effect.

Third, yes, the same points about topical activity would apply to steroidal nasal sprays, and no, steroidal nasal sprays don't cause the "rebound" with continued use like oxymetazoline and they are indeed OK for long term use in most people.

HTH,

Bill

The above information is intended for discussion purposes only and is not meant as specific medical advice for any individual.

 

[John Reinertson]

What follows is what I frequently recommend to divers, pilots, etc.
This may or may not be applicable to your situation/condition.

This is similar to currently recommended approaches to control of asthma, another chronic respiratory inflammation condition.

1. First line therapy for frequent nasal congestion (and frequent difficulty clearing) Is Nasal cortisone sprays. There are several brands available, such as Flonase, Nasonex, Nasacort-AQ, and others.
Almost all of them use the same steroid molecules used in asthma control, and just like in asthma, they are first-line therapy.

2. Second line therapy for chronic congestion is a toss-up between the newer non-sedating antihistamines (specifically Allegra or Claritin) or the mast cell desensitizers/ leukotriene inhibitors ( nasalcrom spray is a mast cell desensitizer and Singulair tablets are a leukotriene inhibitor). Older antihistamines may also work well but have more risk of sedation. (see warning regarding testing new meds before the trip, below.)

All chronic therapies take days to get working full power, but generally offer the most powerful relief with the least risk.

3. For the acute congested nose, (as in I'm diving in a couple hours, what do I do?) we move on to Sudafed (pseudoephedrine) tablets and/or Oxymetazoline nose sprays, which work by acting like adrenaline in the nasal mucous membranes and elsewhere. This reduces swelling by constricting the blood vessels in the swollen tissues (and may have some other effects.)

With Sudafed, adrenaline-like effects on the whole body include increasing alertness, but may possibly raise blood pressure and may lower the threshold for anxiety or panic. There are some theoretical concerns for a modest effect on Oxygen toxicity and or seizure threshold, but there is no real data, and the physiologic rationale is weak. I would personally sweat the anxiety effects more than OXTOX effects, but this is just educated speculation, and many many divers take Sudafed with good benefit.

The most common nose spray adrenaline-analogue is oxymetazoline, marketed in the US as Afrin nasal spray and many others. In US markets, any "12-hour" nasal spray is based on oxymetazoline. These sprays are analogous to albuterol for asthma (salbutamol to the Brits in the audience) and other adrenaline-like asthma inhalers.
One specific caution with adrenaline-like nasal sprays.. when they wear off, the sinuses may become tightly blocked, and you end up with a reverse squeeze on the way up. Use only the twelve hour ones, and use them only for a couple days before graduating to a chronic suppressive treatment.
Using Afrin for a week-long dive trip can lead to rebound and early wearing off by the last part of the trip.

In asthma, these adrenaline-like medicines are referred to as "rescue" medicines, to be used when the chronic suppressive therapy fails. I feel we should look at nasal congestion the same way we look at asthma.

Similar "wearing-off" effects are seen with chronic sudafed. Day 5 of a seven day trip is the wrong time to start feeling worse and having more pain or risk a squeeze.

ANY MEDICATION that is new to you
should be tested well prior to a dive trip. Any one person can develop unusual side effects or a medication allergy, and
130 feet is not the place to find out that your new medicine makes you drowsy or hyper. It would also not be the greatest choice of times to find out your doc's advice didn't work and your ears still won't clear.

Note to the other docs.. the mention of Singulair for nasal congestion is outside current labeling, but has worked in a couple patients, and has a reasonable rationale.

Note to the non-docs.. This is my opinion as to a reasonable approach to treatment of a complex problem. It cannot be taken as a statement that this is the best treatment for you, or that it's the only thing that will work for you. Only you and your physician can determine that. Some patients with anatomic abnormalities of the Eustachian tube witll not respond at all to this.

All I wish is for happy and painless diving for you..
I hope this works for you... if not, I hope you find something else that does and share it with us.

John

 

[scuubaadoo]

I read with intrest your post John and I was wondering why you did not choose diet (no dairy, starch and other mucous producing foods) before going right to a medication. I think the food/exercise link would be a first choice for all who want to consider any diving related medical barrier, if they apply. :bonk: