e-med Home Page
General Practice - our routine services Health Checks - preventative health screening Diving Medicals Travel Clinic Health At Work - e-med your company doctor Download the e-med Medical Dictionary iPhone and Android app
What We Do - all the services at e-med
Your Doctor
Why Us - advantages of using e-med
Join - become a member of e-med
FAQs - Frequently Asked Question about e-med
Medipac - medication for those going abroad

Free medical consultations with the e-med Nurse

e-med Arabic
 

NEW! - The A-Z of Dive Medicine

Frequently Asked Dive Medical Problems
Animal Hazards Bends
Cancer Cardiovascular System
Central Nervous System Dental Problems
Diseases / Viruses Drugs and Diving
Ear Nose and Throat Problems Endocrine
Eye Problems Female Problems
Fitness and Diving Gastrointestinal Problems
Genito-Urinary Longer Articles
Miscellaneous Psychiatric
Respiratory Problems Skin
Trauma, Surgery and Orthopaedic Probs Which Dive Medical?

Drugs and Diving - Beta-Blockers

Dr Jules Eden, dive medicine specialist and founder of e-med, answers divers' questions - as published in Sport Diver magazine:
Text Search this Page

Q - After a particularly stressful day at work I was driving home and felt a bit unusual. I pulled over and noticed my shirt was drenched. Then my chest became uncomfortable... One heart attack later, I was discharged from hospital on a jarful of pills and with instructions to chill out, diet, exercise and generally remove anything exciting from my life. This was 2 months ago. There's no way I'm giving up diving, but my learned dive buddy reckons that these "beta blockers" I've been put on might be harbingers of diving doom. Can you enlighten me on their particular perils, please?

A - Indeed I can, and hopefully it won’t bring forth the wrath of the Four Horsemen of the Apocalypse. Beta receptors are distributed throughout the body, and amongst other things control heart rate and the strength of heart muscle contraction. Beta blockers (they all seem to end in “-ol” for some unfathomable reason) tend to slow the heart down and reduce the force of contraction. Hence they are used to treat high blood pressure and angina, and are often prescribed after heart attacks or heart failure to reduce said organ’s workload. They are also popular with those suffering from “performance anxiety” – musicians, public speakers, stutterers and waning porn stars (note deliberate lost consonant), for example. These drugs could be problematic to a diver, however, for three reasons. Firstly, by blunting the heart’s ability to respond to sudden unexpected demands (eg. strong currents). Secondly, we know that simply immersing a human in water causes a large amount of blood to move from the peripheral to the central circulation, and the resulting back pressure on the lungs can cause leakage of fluid into the alveoli (air-sacs), a risk thought to be elevated by beta blockers. And finally, blockage of beta receptors in the lungs may cause constriction of the airways, particularly in susceptible asthmatics. Ideally therefore, divers should avoid these drugs, if there are alternatives; if not, then the lowest effective dose should be used, and thorough testing carried out to ensure the above risks are minimised.

Q - I wonder if you could give me some advice. I have a colleague wanting to take up open water but has angina. He is on beta blockers (METAPROLOL)and carries a GTN spray. He also has a stent.Is he still able to dive.
Thanks for your help as usual.

A - Someone who has had angina, corrected with a stent [a small plastic tube inserted into the coronary artery to keep it open] is often fine to dive. However your colleague's problem is that he has to have a GTN spray. This is an admission that he still gets the occasional attack of chest pain. He would then spray this under his tongue to help dilate the coronary arteries along with the other blood vessels. It would be hard to do this if he had an attack underwater. The other problem is the beta blockers. These are usually a bar to diving as they affect the heart's response to exercise and also can worsen breathing underwater.
So, a double whammy here.

His only way out is if the GTN spray is cosmetic and he never needs it, or he does a full on exercise ECG to prove all is well. So off to a cardiologist with diving experience. There's a good one in Shrewsbury called Dr Wilmshurst. Find him via the web.

Q - I am taking beta-blockas and am not sure if it is safe to scuba dive - can you advise?

A - The common medical consensus is no you can't. The reason for this is that beta blockers such as atenolol or propranolol really reduce the heart's response to exercise. This wouldn't be too bad on terra firma but underwater it can create problems of fluid collection in the lungs called pulmonary oedema. There is also a risk of getting short of breath due to the drugs having a side effect of narrowing the bronchi of the lungs.

But having said that some diving doctors feel that if you can pass an exercise test and show that the medication has none of the above effects on you then you can be passed as fit.

Personally I would have to say no, but don't give up hope as the conditions that beta blockers are used for can be equally well treated by other tablets which are OK to dive with.

So I would ask your doc to switch the medication if at all possible and you should be fine after a medical assessment.

Q - I've just had a qualified SAA-Dive supervisor asking to dive with us. He's had a bypass, but says he never had a heart attack/angina. His last medical is from January 1999. The operation took place before that date. I know it's not much info, but in your opinion, is he fit to dive?

A - He probably will be if what he says is true. It's surprising that he had a bypass though having never had any cardiac symptoms. Something has to lead a man into the cardiologist to have either a coronary angiogram or a thallium scan that would show the necessary poor blood supply from the cardiac arteries to the heart muscles that then ends up as a bypass. So the fact he says he has never had any angina or even the teeniest heart attack makes we wonder.

However if he is symptom free, and by that I mean he is not just sitting at home watching telly beer in one hand, fag in the other saying there's no chest pain with me doc. He has to prove that on exercise he gets no reduced blood supply to the heart, and this would need an exercise ECG or even better a thallium scan.

He may well have had one of these after the operation and if fine then let him dive with you as long as there hasn't been any symptom return.

Also note that some patients after this sort of op take beta blockers to decrease the workload on the heart, so if he is then he should not risk diving. Its also in his best interests that he does get certified as fit to dive with a proper diving doctor on a regular basis then he wouldn't have any problems from insurance companies if anything were to happen.

Q - My dear wife (49 years of age) uses atenolol for high blood pressure which she hopes to come off from, and as we are going to Egypt soon on a liveaboard. Can you suggest any other alternatives?

We have also been informed that a supplement of B1 will keep the flies away, is this true?

We have had Hepatitis, tetanus and typhoid are there any other jabs needed?

Do you have any other health tips?

A - Dear wife, yes I agree they can be expensive! Atenolol is a beta blocker and as I have pointed out before in previous issues this drug has a risk of causing a build up of fluid in the lungs if she were to exercise more than she was used to. This is called "pulmonary oedema" and results when the heart, which is slowed by the medication, not coping with the amount of blood returning to it, which then oozes out of the capillaries of the lungs into the tissues of the lungs itself. You can recognise someone with this as they are classically short of breath and cough up frothy blood stained sputum rather like the head of a glass of strawberry Cresta if you can remember popular 1970's soft drinks. Atenolol is the most commonly used of the antihypertensives as its cheap and pretty effective, but I've got to advise that she try a non beta blocker, and the best of these for a diver is probably Losartan. So try to get her medication switched afore she goes.

Now the question of what best to keep the flies off. Traditionally one of the Vitamin B subtypes, either B1, B6 or B12 works to keep off mosquitoes rather than flies, but to tell the truth I'm not sure which one it is exactly. But by no means is this to be relied on instead of antimalarials if that occurs where you are. I think the theory is that it makes the skin smell bad to these bugs and wards them off like garlic is also supposed to. But flies are a different matter, bigger and bolder. I guess the key is not to smell like what flies like, or make someone else an attractive proposition. I'll leave that to you! Your shots seem fine as long as its Hep A you've had. As for health tips…plenty.

The most important is to stay well hydrated as this is the biggest contributor to DCS in divers out there. This includes not getting diarrhoea, so watch what you eat there.

Remember the sunscreen and from my experience never be the first to get rigged up before a dive if there's a real slowcoach, standing in 35 degree heat with a wetsuit on for 20 minutes if someone's still in the loo can exhaust you to the point of collapse.

Enjoy the trip.

Q - During the last 2-3 years I have suffered an increased frequency of irregular heart beat. The frequency was such that I consulted my doctor soon after Christmas about the condition. I have been referred to a consultant who has diagnosed atrial fibrillation from the results of a 24 hour ECG. Initially the irregular heart beats occurred when I was at rest, but latterly came on as well during vigorous exercise. I do not experience any other symptoms like shortage of breath during an attack.

At present I swim 1 km in a local pool most mornings without detrimental effect. A recent unmedicated ECG on a running machine conducted by the consultant did not not bring on an attack even with the heart rate at 156.

In the middle of July I am due to holiday in Cuba when I planned to scuba dive. (I have PADI Advanced Open Water Certification) My current medication is 25 mg of Metoprolol twice daily. With my current situation is it safe to dive or would I be a risk to myself and others?

Your guidance would be appreciated.

A - This is an interesting question. Atrial fibrillation or AF is a condition where the heart beat becomes irregular, but in an irregular sort of way. Unsurprisingly doctors describe the rhythm as "irregularly irregular". Diagnosing it is easy but what is harder is finding out why this has happened. It can be due to valve problems in the heart or even thyroid disorders too. So it is important that your cardiologist has excluded the causes of this problem.

If no cause is found then it is known as "lone atrial fibrillation" as it can occur with increasing age on its own. If it is this variety then you have to look at how often it occurs and what happens to your heart and lung function when it is happening. It seems that you are able to exercise well without it coming on but your consultant did not, it seems, check your lung function at the same time, as AF can rarely cause fluid build up in the lungs which would be catastrophic underwater.

The other thing that is a problem in your case is that you are taking a medication known as a beta blocker. Metoprolol will slow your heart rate down, however it also affects your response to exercise [I see you were not on it during the ECG] again leading to a fluid build up in the lungs called pulmonary oedema.

So at this stage I would say that you are at risk and should not dive. There are other treatments for AF that are not beta blockers such as digoxin or disopyramide which it would be fine to dive on, but the medication switch is something you need to discuss with your consultant.

Also to be able to dive you need to prove that the exercise test you do will never bring on a run of AF that would then bring on this pulmonary oedema. You also need an echocardigram to exclude all other heart valve problems. So there's a bit of work to be done before you go, but with non beta blocker well controlled AF you should be fine in the end.

Lastly it has been shown that AF can cause little clots to shoot off around the body called emboli. These are caused by the fact that the blood is not flowing normally around the heart chambers and can clot in the atria. Therefore is a good idea to take an aspirin daily to prevent these clots from forming.

Q - My husband and I did a try-dive during 'Learn to Dive' week and really enjoyed it and we are now thinking about joining our local dive club, however I would appreciate your opinion as to whether it would be OK for my husband to take up diving as a hobby as he is on medication since he received a kidney transplant in late 1999.

He currently takes -
1000mg of Mycophenolate Motefil three times daily,
2mg Tacrolimus twice daily
5mg Amlodipine once daily
3mg Prednisolone once daily
1mg Doxazosin once daily
100mg Metoprolol Tartrate twice daily


He is in good health and is not overweight - your advice on this matter would be much appreciated.

A - A successful kidney transplant where the donor kidney has taken, the blood urea and electrolyte balance is all fine and the side effects of the medication are not causing any debilitation is no bar to diving.

However looking at the meds he is on, one rears its ugly head. Metoprolol.

This is a beta blocker and as mentioned before can cause fluid on the lungs if the dive were to turn strenuous.

Now here's the rub. The metoprolol is to keep his blood pressure down, vital after this sort of operation. In non-renal transplant divers there are other choices of BP tablet, but this may not be the case if he's got someone else's kidney. I think the best option is to go back to the specialist, see if there's another alternate to metoprolol that is not yet another beta blocker, e.g a calcium antagonist and if that's the case then switch. But if his specialist says it can only be metoprolol then I think that he may have to steer clear of sub aqua pursuits.

And finally whilst on the subject of Try Dives, I have just done a medical on a young girl keen to learn to dive after a similar initial experience. Only she was very nearly put off it for life after her session. Why? Well they only went and took her cave diving didn't they after a 20 minute pool session. Makes you realise where all the cowboys have gone.

Q - I currently have pressure on my eyes and was prescribed Timolol Maleate by my Eye Doctor to equalize my eye pressure. I read in your FAQ that glaucoma should not pose any problem to scuba diving. Does it apply to me and my condition? Your help is greatly appreciated.

A - Diving does not exert any more pressure on your eyes so diving with a glaucoma is acceptable. The 2 things you should look out for though are mask squeeze where insufficient air is in your mask which could cause problems, and the fact that very rarely the eye drops you are using can have a wider effect on your body. Timolol is a beta blocker and in theory could reduce your heart rate enough that your tolerance to exercise is affected. So if you have noticed this as an effect you should see a local diving doctor to have a fitness check so that you don't discover that you get short of breath on a dive where a lot of exertion is needed.

(other dive medical questions)



   


Copyright © e-med
 

Prescriptions
Diagnosis - available both on-line and off
Advice
Investigations
Referrals
where we are - physically

 

Search e-med Site

 

 

 

The London Diving Chamber
Visit LDC Website

The Midlands Diving Chamber
Visit MDC Website

Tanked Up Magazine, the magazine for scuba divers and dive clubs
Tanked Up Magazine

LDC Training
LDC Training

Diving Chamber Treatment Trust Hyperbaric Oxygen Therapy (HBOT) Charity
Diving Chamber Treatment Trust