Beta Blockers

Question:
I have a prospective student who takes "Propanol" on a daily basis to prevent migraine headaches. She says they are beta blockers.
Are there any known contraindications from this drug for diving? I will obviously send her to her doctor before enrolling her but would welcome your advice first.

 

Answer:
Beta Bolckers are common drugs used effectively in many circumstances.
However they may have certain collateral effects which can be contraindicating for diving, particularly with respect to their effect of lowering the heart rate, even in the presence of an external situation that may require a higher cardiac performance.
The situation of your prospective student should be evaluated with this aspect in mind and aimed at answering the following question: would this individual's heart rate increase adequately in response to an increased exercise level?
The following is an extract from Alert Diver IV - 2000 which I hope will provide you with useful related information.

Alert Diver IV - 2000
HYPERTENSION, or high blood pressure, is one of the most common medical conditions seen in the diving and general population. Normal blood pressure is generally accepted to be a systolic pressure below 140 and a diastolic pressure below 90 mm Hg, depending on age. Basically, two different sets of complications face a person with hypertension: short-term and long-term. Short-term complications are generally due to extremely high blood pressure; the most significant is the risk of a stroke due to rupture of blood vessels in the brain (called a cerebrovascular accident). Long-term detrimental effects are more common: they include coronary artery disease, kidney disease, congestive heart failure, eye problems and cerebrovascular disease. As long as the individual's blood pressure is under control, the main concerns should be the side effects of medication(s) and evidence of end-organ damage. Divers who have demonstrated adequate control of blood pressure with no significant decrease in performance in the water due to the side effects of drugs, should be able to dive safely. A recent report in a diving medical journal* citing several episodes of acute pulmonary edema in individuals with uncontrolled hypertension while they were diving. Regular physical examinations and appropriate screening for the long-term consequences of hypertension such as coronary artery disease are necessary. Mild hypertension may be controlled with diet and exercise; however, medication is often necessary.

Treatment

 

Many classes of drugs are used to treat hypertension, with varying side effects. Some individuals must change medications after one drug appears to be or becomes ineffective. Others might require more than one drug taken at the same time to keep the blood pressure under control. Classes of drugs known as beta-blockers often cause a decrease in maximum exercise tolerance and may also have some effect on the airways. This normally poses no problem for the average diver. ACE (angiotensin converting enzyme) inhibitors are the preferred class of drugs for treating hypertensive divers; a persistent cough is a possible side effect. Calcium channel blockers are another choice, but lightheadedness when going from a sitting or supine position to standing may be a significant side effect. Diuretics are also frequently used to treat hypertension. This requires careful attention to hydration and electrolyte status. Most anti-hypertensive medications are compatible with diving as long as the side effects experienced by the diver are minimal and their performance in the water is not significantly compromised. Any diver with long-standing high blood pressure should be monitored for secondary effects on the heart and kidneys.