Taking Decongestants and Scuba Diving

Scuba diver under the water.


A scuba diver may want to use a decongestant because he or she 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 canceling a dive at the last minute, and part of hesitation may stem from the fact the diver has been looking forward to diving and 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 their body time to recover from illness before entering the water, even if waiting costs a little money or frustration.

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 the dive. However, be warned that if a decongestant wears off underwater, 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 the air supply diminishes, whether or not their ears equalize.

Taking Decongestants While Diving

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 doctor before using them underwater.

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 cannot be sure whether he or she will have a reaction to a particular decongestant. Give 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, it should not be used while scuba diving.

Choose the Right Decongestant

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 the diver uses to wash out sinus and nasal passages. Saline washes are effective and do not involve any drugs. Try one and time how long it is effective. The saline spray must keep a diver's sinuses clear for the length of a dive.

  • Medicated Nasal Sprays

A medicated nasal spray is a topical medication that reduces swelling and congestion in the sinuses. Medicated nasal sprays clear up lower sinus congestion, but they are less effective at alleviating frontal (forehead) congestion.

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 like drug resistance and dependence. Limit the use of a nasal spray to the period of time suggested on the packaging.

  • Decongestant Pills

Decongestant pills are effective and can alleviate congestion in all sinus cavities. For divers with frontal (forehead) sinus congestion, decongestant pills are probably the best solution. However, decongestant medication may have side effects. Be familiar with medication before diving with it. The effects should last 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 help open Eustachian tubes. However, pseudoephedrine should be used 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 another 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, and 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.

Allergy Medication

A diver who experiences congestion from allergies should treat the congestion with allergy medication unless otherwise advised by a 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.

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 their 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.


Levano, Bryan G., M.S., R.Ph. "Taking medications when you dive." Undercurrents, Volume 46, Number 08, Bluegrass Dive Club, August 2016.

Martin, Lawrence M.D. "Scuba Diving Explained." Lakeside Press, 1997.

"Sinus Congestion." DAN Medical Frequently Asked Questions, Divers Alert Network.

Thalmann, Dr. E.D. "Pseudoephedrine & Enriched-Air Diving?" Divers Alert Network, November/December 1999.

Yeager, Selene. "Mind Your Meds." Scuba Diving, March 2008.