Serc/Betahistine and diving?

[Louie]

Hi all

I suffered from vertigo on my last batch of diving so I got a prescription for Serc/Betahistine (described to me as the only motion-sickness medication that doesn't cause drowsiness).
Since my GP is not too keen on diving-related matters, I'm not too sure if she was aware of possible pitfalls with this particular product in relation to diving.
Does anybody know about Serc and possible adverse effects in diving?

Thanks!

 

[DocVikingo]

Hi Louie,

I suspect you are not having your Serc® (betahistine)prescribed in the US as it is not currently FDA approved. About 30 years ago it was on the market with FDA approval for treating vertigo in Meniere's disease, but approval was withdrawn because of lack of substantial evidence of effectiveness.

Serc® is, however, still commonly prescribed/available OTC in many places around the world, including Europe, Canada & Mexico. Several manufacturers of their respective brand of betahistine apparently were considering seeking FDA approval, but it don't believe any have do so as of yet.

Betahistine is available for pharmacy compounding.

The Serc® package insert cautions against use by patients with bronchial asthma, gastric ulcer, pheochromocytoma (a type of adrenal gland tumor),or those concurrently taking an antihistamine. Reported adverse reactions include gastric upset, nausea, headache skin rashes & itching.

I know of no studies of the effects of diving on betahistine, and I very strongly suspect none have been performed.

Anyone considering diving while on this medication should first receive approval from the prescribing physician, and then have a trial run on the drug on dry land to assess for side effects. My guess is folks who pass these hurdles dive on this medication without problem.

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.

Best regards.

DocVikingo

 

[scubadoc]

In addition to DocVikingo's usual thorough letter about this subject here is a link that might be helpful: http://www.menieres.freeservers.com/special2.htm

Divers should be aware that it is a form of histamine and can worsen bronchial constriction, as noted by DocVikingo. It should not be taken for any inner ear problems other than Meniere's disease.

 

[Louie]

Thank you Scubadoc and Doc Vikingo for the very detailed info on Serc. Yes the prescription was made in England and the prescribing doctor was well aware that I suffer from mild asthma.
Now I'm concerned about using the medication and diving after hearing about possible adverse effects and the lack of research available on the relationship between Serc and diving.
Are there any other medication known to be effective for vertigo that divers can take with the least possible side effects?

 

[scubadoc]

First off - let me state that diving with Meniere's disease is contra-indicated (Bove, 'Medical Examination of Sport Scuba Divers'). An attack of vertigo at depth can be disastrous; add the inner ear problems that can occur at depth and you have a witches brew of risk. (Inner ear barotrauma, inner ear DCS, alternobaric vertigo)

Meclizine is probably the safest medication to take if you must dive at all, it being second only to scopolamine in effectiveness against motion sickness. It's side effects do include drowsiness and there is a warning label that states that one should not drive while taking the drug, a good indication that possibly one should also not dive.

 

[DocVikingo]

Hi Louie,

I believe your concern is warranted on a several fronts:

1. Taking a histamine when there is a documented history of asthma, mild or otherwise, seems very questionable. Prior to medical clearance to dive, a prudent physician would at the very least want an extended period of observation of an asthmatic patient placed on a drug known to cause airways to narrow or close.

2. While you do not mention a dx of Meniere's disease, you do report "vertigo on my last batch of diving," the cause of which apparently has not been determined. The ultimate source of this symptom, to the extent it can be discovered, is rather important both for treatment planning & clearance to dive.

3. There is as yet no evidence that Serc® is going to control your vertigo. As Dr. Campbell has indicated, "an attack of vertigo at depth can be disastrous."

You may wish to contact BASC http://www.bsac.com/ to see if they can direct you to a facility savvy in dive medicine. There are several very effective drugs for controlling vertigo that would not pose the dangers to you that Serc® might.

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.

Best regards.

DocVikingo