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DAN Takes a Look at Over-the-Counter Medications

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Some of the more common questions to DAN medics concern the use of OTCs and their compatibility with safe diving.

By Daniel A. Nord, AEMT-CC, CHT, DAN Medical Information Specialist

As open-water students, we all were drilled about the perils of alcohol and diving. To be sure, there is no exception to the rule that drinking and diving don't mix.

But what about other drugs and diving - specifically over-the-counter medications? Is the line so clear-cut with OTCs?

This is the stuff many dive medical questions are made of - some of the more common questions to DAN medics concern the use of over-the-counter (OTC) medications and their compatibility with safe diving.

The fact that these drugs are easily available over the counter versus a more controlled dispersal as with prescription medications carries with it a sometimes faulty assumption - that all OTCs are completely safe, whether you're topside or underwater.

Not true, say doctors, diving medical specialists - and anecdotal experiences of divers. All drugs are capable of producing some side effects, and even untoward effects in some people when above water.

So what happens when you use OTCs underwater - when you're subjected to the pressures of depth? The answer is not so clear, because little empirical evidence is documented - there has been scant research conducted on the effects of drugs used in a hyperbaric environment. Diving while using most medications is, at best, a matter for you, your doctor and DAN to discuss - before you dive.

CAN'T LIVE WITHOUT 'EM?
Three-fifths of the medications purchased in the United States are nonprescription over-the-counter (OTC) drugs, widely viewed as a cost-effective segment of personal health care. The OTC drug system supports a trend toward self-care and self-medication and is experiencing, on average, an 8- to 10-percent annual growth. Given the popularity of recreational scuba, there is often a concern that some OTCs may not be appropriate for use while diving.

By definition, OTCs are that classification of drugs considered safe for consumer use, based solely on their labeling. When used as directed, they present a minimum risk and a greater margin of safety than prescription (Rx) drugs. They are typically used to treat illnesses which can be easily recognized by the user, in contrast to conditions treated by prescription drugs, which are generally more difficult to assess. Additionally, there are about 300,000 OTC drugs currently on the market, far outnumbering the 65,000 prescription drugs.

The most commonly encountered OTCs - and probably of greatest concern for the sport or recreational diver - fall within the following categories:

  • Antihistamines
  • Decongestants and cough suppressants
  • Anti-inflammatory agents
  • Analgesics
  • Anti-motion sickness preparations

PRESCRIPTION FOR THOUGHT
A diver considering the use of any medication should first give serious thought to the underlying need or reason to take the drug. Does the underlying condition disqualify the individual from diving, or does it compromise his general safety and that of other divers?

The diver, for instance, who requires decongestants in order to equalize his ears and sinuses has increased risk of serious injury from barotrauma. Another example is the seasick diver who, medicated or not, may experience in-water episodic disorientation, vomiting, loss of buoyancy control and embolism as a result of breath-holding or violent diaphragmatic movement.

No drug is completely safe, regardless of the environment. Drugs are chemicals and by design, alter body functions through their therapeutic action. Moreover, they all may have undesirable effects that vary by individual or environment - with sometimes unpredictable results.

BACKGROUND INSIGHTS
What's the first step to take in researching your medications? Review and familiarization with the active ingredients, warnings and directions provided by the manufacturer may offer good insight to the potential for a problem. Here are some examples to learn from.

  • Antihistamines

Most often used to provide symptomatic relief of allergies, colds and motion sickness are antihistamines, with the active ingredients diphenhydramine hydrochloride, triprolidine hydrolochloride and chlorpheniramine maleate. The word "antihistamine" literally denotes a drug with characteristics which are antagonistic to the actions of histamine.

Histamine, in turn, is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, and a dilator of capillaries and arterioles. Antihistamines, then, counteract the symptoms of allergies, colds and motion sickness, but may have side effects. In therapeutic doses, these side effects may include dryness of the mouth, nose and throat, visual disturbances, drowsiness or an undesired sedation or depression - all significant factors that, together or separately, can affect the safety of a dive. Antihistamines can also depress the central nervous system (CNS) and impair a diver's ability to think clearly and react appropriately when the need arises.

  • Decongestants

These are vasoconstricting drugs that cause narrowing of the blood vessels, which often gives a temporary improvement of the nasal airways. Common active ingredients include pseudoephedrine hydrochloride and phenylpropanolamine hydrochloride. Decon- gestants may cause a mild CNS stimulation and can also offer numerous side effects such as nervousness, excitability, restlessness, dizziness, weakness and a forceful or rapid heartbeat.

Medications known to stimulate the central nervous system may have a significant and/or undesirable effect on the diver. Additional precautions or warnings may advise against use by individuals suffering from diabetes, asthma or cardiovascular disease.

  • Anti-Inflammatories & Analgesics

As with any drug, it is wise to consider the underlying condition for taking anti-inflammatories or analgesics. These drugs are generally taken for the temporary relief of minor aches and pains, and although they may provide temporary relief, remember that the injury itself is still present. Limitations in range of movement because of the injury, swelling or pain can place a diver at risk of additional injury. In addition, they may mask mild pain due to decompression sickness, and the diver may subsequently delay seeking treatment.

Active ingredients include naproxen sodium and ibuprofen, with notable side effects such as heartburn, nausea, abdominal pain, headache, dizziness and drowsiness. Standard precautions discourage their use by those with medical disorders involving heartburn, gastric ulcers, bleeding problems or asthma.

With anti-inflammatories or analgesics, perhaps one of the most significant considerations is potential adverse drug interactions in individuals treated with anticoagulants, insulin and nonsteroidal anti-inflammatories (NSAIDs).

  • Anti-Motion Sickness Preparations

It's best not to self-medicate here; specific warnings regularly prohibit the use of these medications prior to consulting a physician. It's generally agreed that - at any time - recreational divers should use these medications with caution.

As with some antihistamines, these medications may typically contain meclizine hydrochloride, dimenhydrinate, diphenhydramine hydrochloride and cyclizine. Common side effects are drowsiness and fatigue. Coupled with impairment of a diver's ability to perform hazardous activities requiring mental alertness or physical coordination, these side effects will definitely not enhance the pleasure of a dive.

UNDERWATER PRESSURES
Any medication that affects the CNS, such as anithistamines, decongestants anti-motion sickness medications, has the potential to interact with increased partial pressures of nitrogen. How? The effects of the medication may increase the chance of nitrogen narcosis. In addition, nitrogen may have a synergistic effect in enhancing the sedative or stimulant quality of the drug.

Furthermore, because of the increased intensity of these effects, a new and unexpected reaction such as panic may occur in an otherwise rational diver. These side effects will vary from diver to diver and from day to day within the same diver - it's simply not possible to predict who will have a reaction while diving.

TOPSIDE SAVVY
What does this all mean for the recreational scuba diver? From a medical perspective, many doctors knowledgeable in diving medicine will quickly advise anyone who requires medication in order to dive to wait the illness out. Other maxims to heed follow below.

Consult your physician when you are ill - your doctor may be able to provide you with a more effective medication and counsel you on diving fitness.

Study all the information supplied with your medication and understand the warnings, precautions and what effects it may have on your body. A trial exposure of at least one or two days prior to diving may help you assess your individual reaction to the drug.

As we often experience in other day-to-day matters, the decision of whether or not to dive is personal and one of acceptable risk. The choice of acceptable risk is a matter of judgment, with careful attention given to the risk versus the benefits, as well as the ability and willingness to deal with possible negative consequences.

Diving should be a positive experience. Dive with care. Remember that both your doctor - and DAN - are there to answer any questions you may have about diving and your health.

Daniel A. Nord, EMT-P, CHT is the director, DAN Medical Services.

OTC Medications Table

Product Category Active Ingredients Sample Warnings
Antihistamines diphenhydramine hydrochloride, triprolidine hydrolochloride, clemastine fumarate, brompheniramine maleate, chlorpheniramine maleate, pyrilamine maleate May cause drowsiness. Do not take this product if you are taking sedatives or tranquilizers, without first consulting your doctor. Use caution when driving a motor vehicle or operating machinery. May cause excitability, especially in children. Do not take this product, unless directed by a doctor, if you have high blood pressure, heart disease, diabetes, thyroid disease, glaucoma, a breathing problem such as emphysema or difficulty in urination due to enlargement of the prostate gland.
Decongestants pseudoephedrine hydrochloride, phenylpropanolamine hydrochloride, phenylephrine hydrochloride, oxymetazoline hydrochloride, naphazoline hydrochloride Do not take this product if you have high blood pressure, heart disease, diabetes, thyroid disease or difficulty in urination due to enlargement of the prostate gland except under the advice and supervision of a physician. Do not take this product if you are presently taking a prescription antihypertensive or antidepressant drug containing a monoamine oxidase inhibitor, except under the advice and supervision of a physician.
Anti-Inflammatories & Analgesics naproxen sodium, ibuprofen, acetaminophen, aspirin, ketoprofen Do not take this product if you have stomach problems (such as heartburn, upset stomach or stomach pain) that persists or recurs, or if you have ulcers or bleeding problems, unless directed by a doctor. if you are taking a prescription drug for anticoagulation (thinning of blood), diabetes, gout or arthritis unless directed by a doctor.
Anti-Motion Sickness meclizine hydrochloride, dimenhydrinate, diphenhydramine hydrochloride, cyclizine Do not take this product if you have asthma, glaucoma, emphysema, chronic pulmonary disease, shortness of breath, difficulty in breathing or difficulty in urination due to enlargement of the prostate gland, unless directed by a doctor. Use caution when driving a motor vehicle or operating machinery. Not for frequent or prolonged use except on advice of a doctor.

From the May/June 1996 Alert Diver