Medicine Planet: Diving and OTC Medications

— -- The over-the-counter medications you usually take may not be safe to use before scuba diving. Find out what medications are dangerous for scuba divers.

Diving and Over-The-Counter Medications | Alan Spira MD, DTMH |

The over-the-counter medications you usually take may not be safe to use before scuba diving. Find out what medications are dangerous for scuba divers. |

Diving and Over-the-Counter Medications: A SummaryThe over-the-counter medications you usually take may not be safe to use before scuba diving. Although very few medications have actually been tested for diving safety, the known side effects of some common OTC drugs are potentially fatal under water. Sedatives, sleep aids, and antihistamines should never be taken prior to diving. Nasal decongestants in general should be treated with caution as well, but one of the most common, pseudoephedrine (Sudafed), has not been shown to pose any additional risk to divers. Avoid motion-sickness medication that causes drowsiness. Analgesics such as aspirin, ibuprofen (Advil) and acetominophen (Tylenol) are generally safe to use.

Before You Go:

Consult a diving or travel medicine specialist prior to a dive if you are considering the use of any drug whose effects under water or at pressure are unknown. Avoid medications that are similar to those with unacceptable side effects. Consider alternatives to medications, such as motion-sickness wristbands. Important Information:Drugs that cause drowsiness can intensify the effects of nitrogen narcosis underwater. There are no good non-sedating antihistamines readily available over the counter in the U.S. The injured or ill diver should consider postponing the dive until she or he is off medication and the situation has resolved satisfactorily. | Drugs and Diving Call for Caution

Most people have a few favorite over-the-counter remedies for their stuffy noses, allergies, motion sickness, headaches, sleeplessness, rashes and so forth. If you are a scuba diver, it's important to know that the drugs that work for you on land may not be safe to take before diving.

Over-the-counter medications can have significant negative effects on a scuba diver's health and performance underwater (as can prescription drugs). Some of the most commonly used over-the-counter drugs are known to be dangerous?even potentially fatal?if taken before diving, but the effects of diving's varying or extreme pressures on many medications are as yet unknown. A drug may not even be effective under water, or may have greater or perhaps unusual side effects, or its action may be unchanged. In the U.S. alone, there are over 60,000 prescription and over 300,000 over-the-counter drugs available; for the majority of them, it has yet to be determined whether or not a diver's safety and health might be compromised by their use.

Consult a diving or travel medicine specialist prior to a dive if you are considering the use of any drug whose effects under water or at pressure are unknown. Try out any new medicine before you leave, under controlled circumstances with a wide margin of safety, to determine possible side effects before your dive. Avoid medications that are similar to those with unacceptable side effects. Give yourself time to try a different formulation if your first choice is contraindicated.

The most commonly available over-the-counter medications can be grouped into five categories: sedatives and sleep aids, antihistamines, decongestants, anti-motion sickness, anti-Inflammatories and analgesics. These are discussed in more detail in the following sections.

Sedatives and Sleep Aids

These drugs should never be taken when diving. Because they cause drowsiness, they can exacerbate the effects of nitrogen narcosis under water. Poor judgement can follow, with serious consequences while diving, when quick and accurate assessments and calculations frequently must be made. Some of these drugs may also cause nausea and vomiting, which can easily result in drowning.

Antihistamines

These can also cause sedation, a potentially dangerous condition while underwater. Although they don't appear to have any other untoward effects when used in healthy divers, they can elevate blood pressure and adversely affect people with heart disease, diabetes, thyroid disease or enlarged prostate, and seriously affect those with emphysema or other chronic obstructive lung disorder, or glaucoma. There are no good non-sedating antihistamines readily available over the counter in the U.S., although there are several good, non-sedating decongestants, such as Sudafed (pseudoephedrine).

Decongestants

These medications in general have the same warnings as antihistamines. Pseudoephedrine (Sudafed, Novafed), however, one of the most common decongestants, does not appear to add any risk to diving. Nasal decongestants are generally not a good idea under water: most wear off too rapidly and you may wind up with a 'rebound' effect, and in worse condition than when you started. People who require decongestants in order to dive are already at increased risk of injury due to higher pressure (barotrauma). If you have to use one of these drugs, stick to a long-lasting version, one that works for around 12 hours. People who overuse or abuse these nasal sprays can become addicted to the chemicals; limit the use of them to just a few days at a time. Some of these drugs should not be taken at the same time as monoamine oxidase-inhibiting anti-depressives (Nardil, Marplan, Parnate).

Anti-motion Sickness

There are several different types of motion-sickness drugs. Many cause side effects similar to those associated with antihistamines and decongestants, particularly drowsiness, which obviously compromises a diver's safety under water. One of the most common, Dramamine (dimenhydrate), is perhaps as well known for making people sleepy as it is for its efficacy against motion sickness. Bonine (meclizine hydrochloride), perhaps less well known, is also very effective against motion sickness but is far less likely to affect a diver's alertness. Acupressure bands worn on the wrist work as well for many people, yet carry no risk of side effects.

Anti-Inflammatories and Analgesics

Non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin, ibuprofen (Motrin, Advil), and naproxen (Naprosyn) are generally safe to use. However, they are not recommended in cases of decompression sickness ("the bends") due to the common belief that they are associated with bleeding in the inner ear. Whether this belief is at all founded has not been proven?and NSAIDS are used often enough in clinical hyperbaric practice to lead many to suspect that this fear may be exaggerated. The usual advice against the use of these drugs by people with peptic ulcer disease, bleeding problems, or asthma still applies.

Acetaminophen, or paracetamol (Tylenol) is generally safe. Any need for a stronger pain medicine is good reason to seriously reconsider diving at all until your condition has improved. Injured divers, or those with problems requiring stronger analgesia, should postpone their dives until they are off the medication and their injury is healed, or other situation satisfactorily resolved.

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