Drugs and Diving


drugs and diving

The use of illicit drugs and even prescribed medication may have effects on the diver in a variety of ways. This article will cover many of the prescription medications and illicit drugs that may affect the commercial diver.

Medications That Potentiate Oxygen Toxicity

Narcotic analgesics, including fentanyl, oxycodone, hydrocodone, tramadol, meperidine, pentazocine, and propoxypheneDisplay footnote number:1,2,14 have the potential to increase susceptibility to oxygen toxicity, thereby predisposing a diver to seizures in high oxygen environments, such as surface decompression (SurDO2) or treatment tables for decompression sickness. Stimulants such as amphetamines (Adderall, Vyvanse, dextroamphetamine), methamphetamines, cocaine, methylphenidate (Ritalin), and phenylpropanolamine (found in over the counter decongestants) also have the potential to lower the seizure threshold in divers. Display footnote number:1,2 Medications used to treat psychiatric conditions including clozapine, phenothiazines, and butyphenones can also lower the seizure threshold and in addition may contribute to nitrogen narcosis. Display footnote number:1, 2 Additional medications that could lower the seizure threshold include anticholinergics (atropine, Cogentin), anticholinesterases, antihistamines, and some muscle relaxants. Other drugs such as oral hypogylcemics (medication used to treat diabetes) and disulfuram (Antabuse used to treat alcoholism) can also lower the seizure threshold.Display footnote number:1,2

Medications That May Protect Against Oxygen Toxicity

Just as there are medications that lower the seizure threshold, there are medications that may protect a diver from having seizures. Often times, these medications can aggravate nitrogen narcosis making them risky for consumption. Barbiturates, benzodiazepines (Xanax, Valium) are medications that are sometimes given to patients to help prevent or treat seizures.Display footnote number:2 They both can cause sedation and would make nitrogen narcosis worse. Even blood pressure medications such as beta blockers (propranolol, Inderal) can protect against oxygen toxicity but at the risk of slowing the heart rate.Display footnote number:2 Some antioxidants, such as Vitamin E, may also help protect against oxygen toxicity, although they have not been shown to alter therapeutic outcomes.

Medications That May Affect the Lungs

Bleomycin is a medication used to treat multiple forms of cancer. It was once thought that anyone that ever took bleomycin should not be exposed to hyperbaric conditions because of fatal respiratory distress. There are some studies that suggest that it may be safe to be exposed to hyperbaric conditions after a period of time has elapsed since treatment with bleomycin.Display footnote number:4 Other medications used to treat cancer that may affect the lungs include ABVD/MOPP, COP/ABVD, dactinomycin, cyclophosphaminde, doxorubricin, vincristine, methotrexate, busulfan, CCNU, BCNU, and carmustine.Display footnote number:5ADVERTISEMENTOpen advertisement in lightboxADVERTISEMENT CAPTION



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Medications that Affect the CNS

Many medications depress the central nervous system and increases the potential for nitrogen narcosis. Opiates (narcotic pain medication), benzodiazepines (Xanax, Valium, Klonopin), and barbiturates all have sedating properties. Some antihistamines (Benadryl, Zantac), many of the older antidepressants (Elavil, Desyrel), and any medication containing alcohol may increase the potential for nitrogen narcosis.

Medications That Affect Glucose

Insulin (Novolog, Humulin, Lantus, etc.) and other medications that lower glucose (metformin, glipizide, etc.) can cause hypoglycemia, especially under hyperbaric conditions. The ADC consensus standards state that divers on these medications are not qualified for commercial diving. Some antidepressants have also been associated with hypoglycemia.Display footnote number:6

Medications That Affect the Heart

Beta blockers (Inderal, propranolol, metoprolol) work by reducing the heart rate and therefore lowering the blood pressure. In the commercial diver, reducing the heart rate may interfere with exercise tolerance and the ability for a diver to do work. Vasopressors such as phenylephrine, used in over the counter decongestants may also affect cardiac output.Display footnote number:7 Other medications can alter the electrocardiogram and predispose the diver to arrhythmias and possible sudden incapacitation or death. Methadone is one such medication that can cause this abnormality.

Medications That Affect Hydration

Diuretics, caffeine and alcohol can all decrease the hydration status of a diver. Dehydration is a major risk factor for decompression sickness. Dehydration may increase the risk of decompression sickness by as much as 10-fold.Display footnote number:8

Medications That May Promote Decompression Sickness

All of the phosphodiesterase inhibitors (Viagra, Cialis, Levitra) and dipyridamole (Persantine) can increase the chance of developing decompression sickness, at least in rats. There are no human studies to date that address these medications in humans.Display footnote number:9 Even decongestants have shown to have a small increase in risk of decompression sickness.Display footnote number:10

Medications That May Protect Against Decompression Sickness

Surprisingly, there are medications that may protect against decompression sickness. The most common class of these medications are the statins, used to lower cholesterol (atorvastatin, pravastatin, rosuvastatin, simvastatin, and others).Display footnote number:11 These medications release nitric oxide and may help prevent decompression sickness. Clopidogrel (Plavix) is a blood thinner that reduces the inflammatory response in the lung of rats and therefore may help prevent decompression sickness.Display footnote number:12 Clopidogrel is, however, contraindicated in diving because of the risk of bleeding. Fluoxetine (Prozac) has been shown to reduce decompression sickness in the rat model, as it has anti-inflammatory properties that may be the mechanism for this effect, but it also depresses the central nervous system.Display footnote number:6ADVERTISEMENTOpen advertisement in lightboxADVERTISEMENT CAPTION



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Illicit Drugs

There are no prospective studies that have been conducted on divers who use illicit drugs. There have been studies questioning recreational divers who have used drugs and had been diving. Up to 3% of the recreational divers questioned had used illicit drugs in the past month. Cannabis, cocaine and ecstasy use was reported within 6 hours of a dive.Display footnote number:13 In the United States, commercial divers in the Gulf of Mexico are under the PHMSA (Pipeline and Hazardous Materials Safety Administration) that is regulated by the Department of Transportation. The drug policy clearly states that no form of cannabis is allowable in drug screens, prescription or otherwise. This conflicts with, but supersedes, states that have approved marijuana for recreational or medical purposes. The narcotic analgesics (hydrocodone, oxycodone, heroin, and many others) can all cause central nervous system depression, increasing the likelihood of nitrogen narcosis. They also decrease the seizure threshold increasing the risk of seizures. Cocaine and amphetamines (Adderall, Vyvanse, methamphetamine) increase the risk of oxygen toxicity and seizures.

Psychoactive Drugs That Are Sold Over the Counter

Cannabidiol (CBD) is a chemical now being sold over the counter in many places. Some of these products contain cannabinoids, specifically those that will show up in a drug screen. The DEA or FDA has not yet regulated these but are likely to come under closer scrutiny in the near future.

Kratom is another drug that is sold over the counter in many places. Kratom has opioid like properties and people can become dependent on it just like other opioids such as hydrocodone, oxycodone and heroin.

Be Aware

There are many medications and illicit drugs that can affect the diver in a variety of ways. There are many medications and illicit drugs that we know nothing about in terms of the effect on diving. There are limits to the information covered in this article. Medications that are not mentioned here does not imply that they are safe. Also, the underlying diseases for which these medications are used may present risks. In addition, stopping some of these medications may induce a withdrawal syndrome that would become potentially fatal, especially in certain situations such as treatment of decompression sickness or saturation diving.

About the author

Dr. Alleman is board certified in Occupational Medicine, Undersea and Hyperbaric Medicine, and Addiction Medicine. All these are subspecialties in the field of preventive medicine. He currently practices in Broussard, LA, with Dr. Joe Serio where they perform diving physicals and treat diving-related incidents.


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