beta blockers

[TSandM]

Diuretics are not "death awaiting". Even the DAN article on cardiovascular problems in divers says that diuretic therapy requires careful attention to hydration and electrolytes, but certainly does not say that they are contraindicated in divers.

Beta blockers can cause some peripheral and pulmonary vasoconstriction, although this is usually balanced by the decrease in cardiac output -- thus their effect in lowering blood pressure. Whether this played a role in the OP's case is unknown, as the phenomenon of immersion pulmonary edema clearly occurs in people in the absence of any beta blockade.

 

[DocVikingo]

Thank you, TSandM, for your insightful clarifications.

I would add that there is a wide variety of drugs, diseases and disorders that can cause erectile dysfunction and that ED is not an absolute consequence of antihypertensive medication at modest doses.

A male's ability to achieve an erection in and of itself is not a sensible index of the possible contribution of atenolol, other beta blockers or other antihypertensives to exercise intolerance, pulmonary vasoconstriction, hemoptysis, SIPE or any other risk to scuba of which I can conceive.

Regards,

DocVikingo

 

[pescador775]

TS&M, yes, DAN, of course. How could I forget about them? Let's say that the first contraindication of diuretics for divers could be signalled by paralysis. Oh, wait, DAN says "be careful and take your fluids". That applies to all divers, not just those on meds. So, where does that leave the diver? Who knows, but it leaves DAN in the clear.

It is common knowledge that Beta blockers can have "sexual side effects". If an otherwise healthy diver who is taking blockers cannot get an erection, it is time to stop diving pending examination, IMO. A constricted blood vessel may become the site of a blockage, particularly so as older divers with atherosclerosis are more likely to be consuming the blocker. It is sometimes called "undeserved" bends and the site of the blockage could be the spine. Ouch.

As to your comments about "lowering blood pressure". The people who typically get the edema are young, trained athletes. Presumably their resting BP is low. However, it does seem likely that their peak pressures could be higher than a subject on blocker.. Certainly, a lower cardiac output in a blocker dependent subject might mitigate against this type of exercise induced problem. Frankly, I'm not willing to investigate this complicated subject further but as a variable, it looks suspicious.

 

[TSandM]

pescador, I think you quite unfairly malign DAN. First of all, they have one of the best databases on decompression sickness events (as they insure them). Secondly, as an insurance company, they are very much in the business of trying to identify predisposing factors to hits. If they can reduce the frequency of events, they reduce their payouts. It would be quite against their own interests to advise divers it was safe to take a medication that was likely to increase the chances of DCS.

I would be very interested in any case report of spinal cord symptoms after diving which were shown to be related to atherosclerosis. I have not read anything that suggests that Type II hits are more common in divers with atherosclerotic disease.

 

[pescador775]

OK, I don't have the data. It may not exist. I'll look for it. Meanwhile here's a bone:

LONDON (Reuters) Jun 28 - A major shake-up in the way doctors are being advised to treat high blood pressure was announced by Britain's drugs watchdog on Wednesday.

GPs will no longer offer drugs called beta blockers as a first treatment for the condition.

Instead black people suffering from high blood pressure and all those over 55 will be given a type of medication known as a calcium channel blocker, or a diuretic drug.

Those under 55 will first be treated with a class of medicine known as an ACE inhibitor.

Patients can also be offered a combination of the three drugs.

The advice comes after research showed the newer drugs carry less risk of a heart attack or stroke. (snipped)