Decongestants and Scuba Diving

Man inhaling decongestant
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"As an open water instructor, I issued a blanket statement whenever a dive student asked me if they could dive with decongestants: No. The reason was not that the decongestants themselves were dangerous, but that the underlying condition causing the student to want to take the decongestants was.

A dive student has little experience underwater, and may not be familiar with the way his body reacts to the underwater environment. He may not know at what point a temporary medical condition such as a cold or congestion makes diving unsafe.

Now that I work with experienced technical divers, it is not uncommon for one of my divers to pop a pill half an hour before diving and experience no negative consequences. Diving with decongestants can be done safely, but with caution and only under certain conditions."

Do Not Dive With Decongestants If You Are Really Sick

A scuba diver may want to use a decongestant because he is sick and does not want to cancel a dive. Part of this hesitation to cancel a dive may be caused by the fact that the diver is likely to lose money if he cancels a dive at the last minute, and part of hesitation may stem from the fact the diver has been looking forward to diving and really wants to get in the water.

While this enthusiasm for the sport is to be applauded, it is not a good idea for a diver to use medicine to mask the symptoms of a serious cold or flu.

Diving is a safe and enjoyable activity, but only when done properly. A sick diver is likely to be dehydrated, lethargic, and less able to concentrate underwater. Such a diver may be at a greater risk of decompression sickness or of making a stupid mistake that could lead to injury. A sick diver should give his body time to recover from his illness before entering the water, even if waiting costs him a little money or frustration.

Do Use Decongestants to Clear Up Mild Head Congestion

The Diver's Alert Network (DAN), as well as various scuba diving doctors and publications, state that decongestants can be used to clear up sinus and head congestion when scuba diving. Using a decongestant is appropriate in the case that a diver experiences congestion related to travel, breathing extremely dry air from a scuba tank, or another factor unrelated to illness.

If a diver has uncomplicated congestion with no other symptoms, decongestants may be used to allow him to dive. However, be warned that if a decongestant wears off underwater water, the congestion may return and make it difficult for a diver's ears to equalize during ascent. This is particularly dangerous because a diver will be forced to ascend as his air supply diminishes, whether or not his ears will equalize.

Never Use a Decongestant for the First Time on a Dive

Using any medication underwater can be dangerous due to potential side effects that may affect a diver's abilities or physical state. For this reason, divers who take prescription medications must clear their use with a diving doctor before using them underwater. Unfortunately, many divers employ over-the-counter medications while scuba diving without a second thought.

Most decongestants have a long list of side effects on the packaging. For the majority of people who do not experience these side effects, diving with decongestants should be safe. However, a diver can not be sure whether he will have a reaction to a particular decongestant until he tries it, so he should be sure to give his chosen decongestant a test run before using it underwater. If a diver experiences sleepiness, confusion, agitation, increased heart rate, or any other side effect from the medication, he should not use it while scuba diving.

Choose the Decongestant That Best Fits Your Needs

Decongestants are available in a variety of forms, including nasal washes, sprays, and pills. Each type of decongestant has advantages and disadvantages.

Saline Nasal Washes

A saline nasal wash is a sterile, saline fluid that the diver squirts up his nose to wash out his sinus and nasal passages. Saline washes are surprisingly effective and do not involve any drugs. Before blowing money on a decongestant medication, determine whether a saline nasal wash will clear your sinuses. Try one out and time how long it is effective; the saline spray must keep a diver's sinuses clear for at least the length of a dive.

Medicated Nasal Sprays

A medicated nasal spray is topical medication that reduces swelling and congestion in the sinuses, such as Afrin. Medicated nasal sprays work well to clear up lower sinus congestion, but the author has found that they are less effective at alleviating frontal (forehead) congestion because it is difficult to get the medicine into this area.

Medicated nasal sprays may last longer than many decongestant pills, and they typically do not have side effects. However, using a medicated nasal spray for an extended period of time can cause problems such as drug resistance and dependence. Limit the use of a nasal spray to the period of time suggested on the packaging. For Afrin, the maximum duration of use is three days.

Decongestant Pills

Decongestant pills are extremely effective at clearing up congestion and can alleviate congestion in all sinus cavities easily. For divers with frontal (forehead) sinus congestion, decongestant pills are probably the best solution. However, decongestant medication may have side effects. As previously stated, it is important for a diver to be familiar with a medication before diving with it. The effects of the decongestant should last at least the duration of a dive, to avoid the return of congestion underwater and the possibility of a reverse block.

Pseudoephedrine (Sudafed) and Scuba Diving

Many divers swear by pseudoephedrine medications such as Sudafed. They alleviate sinus congestion and helps to open Eustachian tubes. However, pseudoephedrine should be employed with caution for several reasons.

  1. Individuals who experience side effects from pseudoephedrine may experience strong side effects. Don't take this medication for the first time while gearing up before a dive, no matter how strongly your buddies praise it.
  2. Pseudoephedrine may increase the risk of oxygen toxicity in humans; it has been proven to do so in rats. Without getting too technical, pseudoephedrine is a central nervous system stimulator and might increase a diver's susceptibility to CNS oxygen toxicity. This has not been proven, but given that the consequences of oxygen toxicity are convulsions and drowning, it seems wise to avoid the use of pseudoephedrine on any dive that will expose a diver to high partial pressures of oxygen, including very deep air dives, nitrox dives, and some trimix dives.
  3. Pseudoephedrine is illegal in some countries. The active ingredient can be used by naughty chemists to make some rather nasty recreational drugs. For this reason, the purchase (and even possession) of medications containing pseudoephedrine may be prohibited or strictly regulated in some countries. For example, Sudafed is not available over-the-counter in Mexico. Divers who plan to carry pseudoephedrine pills into a country should make sure that they are legally allowed to do so before packing their bags.

    Decongestant Mixing and Overuse

    Some medications may be used simultaneously with no side effects and some may not. Be careful about mixing any medications (prescription or otherwise) with decongestants. It is wise to consult with a doctor to determine whether two medications can be safely mixed.

    Do not take multiple brands of decongestant pills at once in a misguided attempt to completely eradicate congestion. Do not take more than the recommended dosage of a single type of pill. In most cases, this will not increase the benefits of the medication, but it may increase the side effects.

    The one exception to this rule is topical nasal sprays and pseudoephedrine. Generally, these two may be taken simultaneously.

    Allergies Require Allergy Medication

    A diver who experiences congestion from allergies should treat the congestion with allergy medication unless otherwise advised by his doctor. Be sure to clear an allergy medication for diving with a doctor, and confirm that no side effects are experienced before using it underwater for the first time.

    The Take-Home Message About Decongestants and Diving

    Divers often want to use decongestants to enable them to scuba dive while they are ill. This is highly inadvisable. However, a diver who has simple, mild congestion and does not experience side effects from his chosen medication should be able to dive safely with the decongestant.

    Remember that if a decongestant wears off underwater, a diver may be at risk for a reverse block and have difficulty equalizing his ears during ascent. In all cases, be sure to follow directions on the medication labeling regarding dosage and duration of use. Finally, try a simple saline spray before turning to drugs. Many divers find saline nasal sprays to be highly effective.


    Diver's Alert Network. "Taking Medications When You Dive" By Bryan G. Levano, M.S., R.Ph.

    Diver's Alert Network. "Pseudoephedrine & Enriched-Air Diving?" By Dr. E.D. Thalmann, DAN Assistant Medical Director.

    Scuba "Mind Your Meds" By Selene Yeager

    "Scuba Diving Explained" by Lawrence Martin, M.D.

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