Cardiovascular Drugs and Diving

Guidelines to use in considering the relationships between all drugs and diving:

  • Consider the condition/illness/disease for which the medication is being given. Go to our ‘Fitness to Dive’ web page and check to see if your condition could be dangerous underwater.
  • Are there any effects of the drug that alter consciousness or cause alteration in decision making ability.
  • Check in the linked ‘Databases’ below for any side effects of the drug that could be dangerous underwater.
  • Consider complex relationships between drugs, the individual, other medications, diet and the conditions for which the drugs are taken.

Use these Databases to Search for Your Medication, then apply the above diving factors in your decision to dive:

  • RxList
  • Intelihealth Drug database
  • Medline Plus
  • Infomed
  • RxMed

Many sport diving candidates are taking a variety of cardiac and blood pressure medications. It is therefore necessary to understand the response of patients taking such medications to exercise and diving.


Poor response to exercise and fainting are two things that can happen to patients on large doses of antihypertensive medication. This is due to the loss of normal control mechanisms of the vascular system. Because of these effects, diving candidates using these drugs exercise tests to rule out inadequate blood pressure response during exercise. Limitations to moderate exercise due to dyspnea, weakness, dizziness or palpitations should alert the physician to do careful exercise screening prior to approval for diving.

Beta blockers

Patients taking beta adrenergic blocking drugs may also have unique problems with exercise. Some of these patients may have significant inability of the heart to respond to exercise; therefore, measurement of heart rate does not provide the index of exercise work load which is generally found in the patients who have normal autonomic responsiveness. Individuals who are in good physical condition should generally have little problem with recreational diving while on this drug.
When stress testing a patient on beta blockade, a relative maximum heart rate can be achieved by comparing the perceived exercise score with the heart rate when the patient has significant fatigue. Heart rate response to exercise however, does not indicate a poor physiologic response in this case. There is some suggestion that beta adrenergic blockade will inhibit maximum exercise performance.

Diving should not provoke maximum work demand. However, it is important to advise divers taking beta blockers to avoid extreme exercise since their maximum capacity may by inhibited by beta blockade. Exercise testing should be done while taking the beta blocker and in the presence of the usual therapeutic regimen. Patients on nitrate medications for coronary disease generally have severe enough coronary disease that they should not dive.

Beta blockers can also be asociated with bronchial constriction, an increased risk factor with diving.


These drugs do not contravene diving per se, but should indicate to the diver and his physician that there might be some possibility of coronary artery disease – which is a definite risk to the diver.

Important cardiovascular medications and diving

DrugAdverse Effect
AntiarrhythmicsDisease process
Lung fibrosis with amiodarone
process (photosensitivity
with with tetracyclines)
AspirinIncreased bleeding
Beta BlockersDecreased
exercise capacity
Bronchial constriction
Coumadin Bleeding with barotrauma,
possible worsening of spinal DCS
Digitalisdisease process
Diureticsdehydration, increased risk for


Ernest S. Campbell, M.D., FACS

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