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University of Pittsburgh Researchers Find Some Over-The-Counter Medicine May Affect Scuba Divers’ Performance

PITTSBURGH, August 30, 2000 — Scuba divers should think twice about taking certain over- the-counter medications before diving, say emergency physicians at the University of Pittsburgh School of Medicine who conducted studies on the effects of Dramamine® and Sudafed® on scuba divers’ performance. The results of the studies, published in the September issue of Pharmacotherapy, are among the first to have been conducted in hyperbaric oxygen (HBO) chambers, where pressures experienced by divers at different depths can be simulated accurately.

While most divers know it is ill-advised to take any kind of medication before a dive, many will take Dramamine® to combat the effects of seasickness or take Sudafed® to ease pressure in the sinus and ears. But, the researchers wondered might divers be subjecting themselves to greater risks for decompression sickness and nitrogen narcosis?

Nitrogen narcosis and decompression sickness result from inhaling compressed air. Nitrogen narcosis is attributed to the depth of a dive and occurs when divers become disoriented and, in rare cases, become unconscious. It can be remedied by ascending back to the surface of the water. Decompression sickness is associated with the length of a dive and is caused when nitrogen bubbles arise in the blood, resulting in severe pain. Unlike nitrogen narcosis, decompression sickness can lead to permanent damage. Potential neurologic complications include stroke and paralysis.

According to the results of their studies, the researchers found Sudafed® to be relatively "safe," but determined that Dramamine® could have serious consequences on a diver’s mental functioning and judgment.

"Our findings indicate that Sudafed® is unlikely to cause problems for divers. But, Dramamine® should be avoided prior to diving because of its adverse affects on mental agility," says David McD Taylor, M.D., principal investigator of the study, who is now at the Royal Melbourne Hospital, Victoria, Australia.

"Hopefully the results of these studies will make divers more knowledgeable, allowing them to dive safely," says Kevin O’Toole, M.D., F.A.C.E.P., associate professor of emergency medicine, director of the hyperbaric medicine program and co-principal investigator of the study.

In both studies, researchers looked at 30 people recruited from local diving clubs to determine the psychometric and cardiac effects of both drugs. All participants were required to be active scuba divers and had to be at least 18 years old. The study used a double-blind, placebo-controlled, crossover design -- whereby participants eventually received both the placebo and each study drug, but neither the subjects nor the researchers knew which drugs they were taking.

Each participant came for three separate testing sessions at least one week apart. Each session involved the ingestion of the drug or placebo and testing inside the HBO chamber under two simulated diving conditions -- one just under three feet below sea level and the other at 66 feet below sea level, a common depth for recreational diving. While in the simulated diving chamber, all subjects were connected to a cardiac monitor to record both heart rate and cardiac rhythm. A total of seven separate tests were performed to study cognitive and behavioral patterns.

HBO chambers are typically used to treat decompression sickness in divers who get into trouble during ascent back to the water’s surface. The HBO facility at UPMC is used primarily for carbon monoxide poisoning, wounds that are not healing, burns and other problems that may be helped by increasing the amount of oxygen delivered to the tissues.

The department of emergency medicine is widely known for its academic programs and research. The residency program, which started in 1981, has become one of the most competitive in the nation and trains more fellows in the fields of toxicology, prehospital care, research, and education and injury control than any other academic institution in the country.

The diving studies were supported by a grant from the Pittsburgh Emergency Medicine Foundation.

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