Diving on Drugs

by Sue Endicott, MSN, RN:


“Is scuba diving inherently safe?”  That was the question I asked as part of my informal survey assessing the image divers and non-divers alike have of our sport.  As it turns out the majority of the answers were “yes” it is a safe sport.  That being said, like any other sport there are still risks involved and like anything else we do in life, pre-planning and mitigation always lead to better results.

The topic for this article is diving and drugs.  This covers the spectrum from illicit street drugs to medications prescribed by a physician and taken on a daily basis.  Some medications have absolutely no impact on your diving and safety, while others should be considered absolutely contraindicated to use while diving.

It is our mission to demystify some of the information out there regarding the use of medication while diving, talk about staying safe, and remind everyone to involve the experts who are familiar with diving medicine.

Many of us have had to get a diving physical at one point or another in our diving careers.  Utilize a physician who is familiar with diving.  There is also a wealth of information on the medical release forms which can aid physicians (even when new conditions arise) in determining what are considered possible, and even sometimes temporary, contraindications to diving, to those that are absolute contraindications to diving.  You can access this by going to here.

Don’t make decisions on your own about what health conditions are acceptable, what medications are safe to take while diving, and what medical history you may have which should either make you reconsider diving temporarily, or be dangerous enough to end your dive days forever.

Although there is not one specific list which includes every medication and whether it is safe for anyone under every specific type of dive scenario, there are general rules and suggestions you can follow which should help you make the safest and most informed decision.  Finally, one of the most important things to consider while discussing this topic is what medical condition led to having to take the medication to begin with.  The majority of the medications we are discussing today help us manage diseases and their signs and symptoms, not cure them.  In some cases if the condition is serious enough to require medication, it may indicate you are not healthy enough to dive.  At that point the medication should almost become a secondary concern and the health issue should be the guiding force in deciding whether or not it is safe for you to continue diving.

General Considerations

What condition led the physician to determine you needed this particular medication?

If you have something relatively minor like well managed hypothyroid disease and you take medication for that there is probably not an issue diving on this medication.  If you have been diagnosed with heart disease, or had a heart attack, the strenuous work of diving is probably not the best choice of exercise for you.

What was the doctor’s response when you asked if you could take this medication while diving?

Again a physician with knowledge of diving is critical and paying attention to what they tell you should be non-negotiable.  I would be devastated if I was told I couldn’t dive anymore, however if I had a condition which warranted that decision and was told by an expert I should give it up, I reluctantly, albeit kicking and screaming,  would.  If you didn’t pay attention to that advice not only would you put yourself in danger you also put those around you in a difficult place as well.

How long have you been taking it?

This depends on the medication.  If it is for a serious condition you should do a trial run on land for a good period of time, and again consult your physician before diving on the medication.  Some of the more benign medications could probably be safely tried for a few days and if there are no issues it should be safe to dive on it.  It also helps to consider the medication carefully.  Some have known serious side effects and others do not.  The most likely scenario would be for the physician to get you on the medication for a period of time to see how it impacts you, and see if you have any side effects which could put you in danger while diving.

What are the known side effects?

This is what is meant by considering the medication carefully.  Consult with a physician or pharmacist and discuss the possible complications, then think it through.  If dizziness or lightheadedness are side effects you don’t want to dive on that medication as both of those conditions could lead to fainting and possible drowning.  Dry mouth could even be a problem as breathing through a regulator dries out your mouth to begin with, and this could exacerbate this situation.

Have you had any side effects?

During your trial run on land before diving with a new medication pay close attention to see if you experience any of the possible side effects from this medication.  Not everyone has every side effect mentioned in the drug packaging so see how it impacts you.

Have you been diving on it before?

Once your trial on land has been completed and you are clear to dive, note carefully how you feel while diving on this new medication.  Once you have been diving several times while taking it, it is still a good idea to remain cautious and aware for possible reactions and side effects.

Remember it is not only the medication, but also the underlying condition, which should be part of your decision-making to dive or sit it out.

Categories of Medications

Medications for Cardiac Issues

If you have been diagnosed with heart disease, or have had a heart attack, the strenuous work of diving may not be the best choice of exercise for you.  Some of the medications associated with heart issues can pose serious problems to divers.  Some blood pressure medications can cause dizziness.  Some drugs used to assist with angina such as Beta-blockers act to reduce the workload of the heart; however this may reduce the ability of the heart to contract with sufficient force to provide the blood supply needed to deal with an emergency situation.

Medications for Respiratory Issues

Asthma is a common condition in the population today.  It is essentially an inflammation of the airway passages of the lungs and causes reduced airway size, spasm of the airways, and reduced airflow.  There are medications that are inhaled to treat these conditions but they do not cure them.  In addition, there is usually some degree of obstruction all the time and this, coupled with any panic while diving, could be deadly for the diver.  Most experts consider asthma and the associated drugs to treat it to be contraindications to diving.

Medications for Neurological Issues

Antianxiety medication such as Valium should be considered dangerous when it comes to diving.  Not only because of the sedative effects of the medication but also for the underlying reason people are taking them which is usually some sort of panic disorder.  These and other similar medications can cause drowsiness and impaired judgment which could possibly be impacted by nitrogen narcosis.  For these reasons these medications are considered incompatible with diving.

Antidepressants are a controversial topic.  I know people who have been on the same antidepressant for years and logged hundreds of dives.  Some other schools of thought state they cause potentially hazardous side effects including irregular heart rhythms, particularly if it is a new medication for the diver.   This is a perfect example of what we discussed above about a trial run on the medication to see about side effects, how long a person has been taking the medication, and how they have reacted to it.  Each case should be considered individually.

Drugs used to treat serious neurological disorders such as schizophrenia and epilepsy should be seen as contraindications to diving not only because of the side effects of the drugs but the problems with the underlying conditions.

Medications for Diabetes

People with diabetes are prone to variations in blood sugar levels especially with strenuous exercise.  The potential for these rapid changes in blood sugar and the catastrophic results which could occur, such as loss of consciousness and drowning, typically cause most medical professionals in the research to view diving as incompatible with diabetes.

Medications for Gastrointestinal Disorders

This category depends on the underlying reason for taking the medication.  If this person is experiencing nausea and vomiting they are at risk for dehydration and probably should skip the dive that day.  Another factor mentioned in the literature was the consideration regarding the risk of gas trapping which could cause barotrauma on ascent.  Consider these cases carefully and on an individual basis.

Seasickness is one of the most common disorders in this category.  Nothing can turn a lovely dive day into a trip to hell faster than getting seasick.  The best action here is prevention.  There are a multitude of medications including pills, patches and natural remedies which can help prevent you from becoming sea sick.  Do your homework and research your choice of anti-seasickness medications so you know what the potential side effects are.  These medications may sound relatively benign but there is always the potential for side effects, most commonly drowsiness, so the brands that list that as a possible complication are best to avoid if you plan on diving.  Also stay out in the fresh air and avoid the heat at all costs.  Unfortunately, once it is on, that proverbial ship has sailed and it is nearly impossible to treat sea sickness after the fact, so be proactive here.

Medications for Temporary Issues

Colds and Congestion

Treating the congestion that comes along with a cold or allergies can be one of the bigger concerns in this category.  Those who are congested are at risk for barotrauma at depth.  Also people often take some sort of decongestant prior to diving but the problem is those can wear off while you are at depth and cause serious problems.  Most of these medications cause dizziness and drowsiness as well which, as we have discussed, can be dangerous while diving.


The biggest concern that comes to mind when considering diving on antibiotics is what has a person so sick they need to be on antibiotics, and if they are that sick are they fit to dive?  I realize people take antibiotics for many different reasons, so check with your doctor on this one for sure.  Also be aware that some of these drugs can cause sensitivity to the sun so be sure to use your sunscreen and stay in the shade on the boat.


Aspirin may seem like a relatively benign drug, but when combined with diving, can have serious consequences.  Aspirin can lead to bleeding and if a diver develops decompression sickness or inner ear issues the increased bleeding from aspirin can greatly magnify the situation.

Acetaminophen is a better choice for pain as there are fewer side effects including less stomach upset and it does not cause bleeding problems.

Narcotic pain relievers can cause serious side effects including impaired judgment, dizziness, and fatigue.  Someone experiencing pain to the degree that they require narcotic pain relievers should not be diving for that day.

Sleep Medication

Whether over the counter or prescription, these medications can impact your ability to dive safely.  Often times these medications leave you with a sleep “hangover” where you are not fully alert and awake for a period of time after waking up.  If this period of time rolls over into dive time your judgment may be impaired, you may have a slowed reaction time, and place yourself and others in danger.  Avoid sleep aids the night before diving.  Get plenty of rest and know it is better to be naturally a little tired in the  morning than tired from the hangover effect, besides once you hit that cool water you should wake up pretty quickly.

Erectile Dysfunction

This specific question was brought up so it is worthy of being addressed.  Simply diving with erectile dysfunction (ED), in the absence of any other precluding factors, poses no risk whatsoever.  This changes when we begin to talk about taking medication for this condition.  ED drugs were originally developed to treat heart disease and high blood pressure.  Men in the study reported an increase in erections while on the drug so it was repurposed as an ED drug.

The problem occurs when someone on these drugs is also taking anything which can potentially lower their blood pressure, which should never be done, as the combination of those drugs can lead to a dangerously low blood pressure.  Side effects could include loss of consciousness and other cardiac issues up to cardiac arrest.  Reported side effects from ED drugs alone include headache, nausea, vomiting, and nasal congestion.

If you have taken these drugs before with no issues then diving should be okay for you but again it is critical to seek the advice of an expert to determine if the situation is safe for you, especially if you take other medications, and ALWAYS before diving if you have been given a new prescription.  Also, ED drugs can stay in your system for days so it is imperative you keep that in mind particularly if any of the above scenarios apply.

Alcohol and Illicit Drugs


Diving under the influence is just a recipe for disaster.  It is even possible to be considered under the influence on the day after a heavy night of drinking as the degree to which the liver can metabolize alcohol varies.

Alcohol is associated with a high risk of drowning, impaired judgment, impaired pumping ability of the heart, and hypothermia.  Save cocktail hour until after you dive and go easy the night before.


Much like alcohol, this drug leads to impaired judgment which can be increased with nitrogen narcosis.  Many people who smoke marijuana have chronic bronchitis which can make a person vulnerable to airway spasm and possibly barotrauma.  Hypothermia is another potential side effect.


This drug has been associated with cardiac rhythm disturbances and high blood pressure as well as impaired judgment.


These were mentioned under pain relievers and should be avoided at all costs while diving.

Due to the serious nature of the side effects associated with alcohol and illicit drug use, you should not use these substances if you plan on diving.


Whatever you decide, make sure it is an informed decision.  Avoid alcohol and illicit drugs, and when it comes to prescription medication take the medication on land for several weeks prior to going diving while taking it.  This will allow you to avoid any surprises which might happen as your body begins to get used to taking the medication.  It will be much easier and safer to deal with adverse effects while on dry land rather than out on a boat, or worse underwater.  Also discuss your situation with a professional, do your research and make a smart informed decision on diving for that particular day.  Take care of things the right way and you will have many more great days diving, push your luck and you may face disaster and your dive days may be over permanently … or worse you could end up as an unnecessary diving fatality.

Until next time – dive safe and have fun!

Sue Endicott, MSN, RN
Director of Education
Dive 1st Aid

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