Hi Ken,
To answer your specific question, there is no research that I am aware of investigating the possible increased risk of SUSTAINING nitrogen narcosis occasioned by use of Triptone (dimenhydrinate).
Such study requires funding, and there is extremely limited financial support for this line of inquiry. There is an amazing dearth of research on the effects of various medications, seasickness & otherwise, on fitness to dive.
The single study of dimenhydrinate & diving of which I am aware suggested that taking the drug can EXACERBATE or be ADDITIVE with certain effects of nitrogen narcosis. It resulted in a significant decrease in scores of mental flexibility on a paper-and-pencil test involving the sequential connection of number-letter sequences. This is perhaps not surprising given that the most common side-effect of dimenhydrinate is sedation which can vary from slight drowsiness to deep sleep, and including inability to concentrate, lack of energy, fatigue, dizziness, muscular weakness and incoordination. It's worth noting that neither of these drugs is permitted for commercial pilots.
In all fairness to the drug, it did not significantly impair mental function relative to control groups on 6 other psychometric devices.
As a general primer on dealing with mal de mer, here's an updated version of a piece from my Jan/Feb '00 "Ask RSD" column in "Rodale's Scuba Diving":
"Sea sickness, which shows wide variation in susceptibility among individuals, is not yet fully understood. It is believed to occur when portions of the brain tasked with maintaining balance receive input from the eyes, inner ear, muscles and joints that is inconsistent and unexpected over an extended period of time.
Prevention is a first step. Avoid fatigue and get adequate rest. Eat modestly, avoiding greasy, fatty, acidic and spicy foods. Don't skip breakfast, but stick to bland foods like toast, rolls and cereal. Go easy on tea and coffee, and very, very easy on alcoholic beverages. When on the boat, don't get overheated--stay under a sunshade, don't put on your protective suit until necessary, and get in the water as soon as possible. Search out a spot low and in the center where motion is minimized, face forward, focus your eyes on a fixed object on the horizon or elsewhere, avoid unnecessary neck movements and stay out of exhaust fumes. Do not go below, read anything or look through binoculars. If you must vomit, do so freely, but not anywhere on the boat, and especially not in the marine toilet.
There are plenty of medications available, and you may wish to discuss this with your physician. Among those reported to be the most effective are meclizine and scopolamine. Prescription strength meclizine commonly comes as Antivert. Scopolamine can be delivered through a transdermal patch, Transderm Scop, orally, and as a gel applied to the wrists. The gel reportedly works faster, but not as long as the patch. Scopolamine is the US Navy's first line sea sickness drug, including for divers, and DAN approves it with a trial run. Occasionally Phenergan, whose primary indication is as a sedative, is recommended. It can cause very serious drowsiness, however, and is sometimes prescribed in combination with a stimulant to counteract this. The above drugs are prescription only and have reported side effects, most commonly dryness of the mouth and drowsiness. They may also cause blurred vision, dizziness and even confusion in some users, and it is recommended to carefully discuss their use with your physician, give them a trial run prior to use in conjunction with diving, and take them only according to instructions.
Over the counter (OTC) preparations include Bonine, Dramamine (Not recommended due to demonstrated adverse effects on alertness & performance), Dramamine II (Advertised as a "less drowsy" formula. As this implies, be aware that some individuals still do experience some degree of drowsiness.) and Triptone (Same active ingredient as original Dramamine, dimenhydrinate, so draw your own conclusions) . A British drug, Stugeron (cinnarizine), has been mentioned by several sources as an effective treatment (Have seen a recent research piece suggesting impairment in divers at higher doses), but it is not yet available in the US. Those diving in such places as Mexico & the British Virgin Islands can find it. Many report these OTC medications most effective if taken at bedtime the night prior to diving, with a second dose about an hour before diving, although recommended dosage amounts should of course not be exceeded. These medications often cause significant dryness of the mouth. Stay very well hydrated.
Considering more "natural" remedies, ginger is frequently mentioned, which can be taken in powdered, crystallized or root form, or as ginger snaps, ginger ale, or tea. As heartburn with the use of ginger has been reported, also pack an antacid. Others swear by wrist straps, such as 'Sea Bands,' usually wooden or plastic balls on elastic bands which are placed so as to exert pressure on an acupressure point on the inside of the wrist. There are also 'artificial-horizon' glasses. Even aromatherapy has been tried, with a combination of mandarin, peppermint, spearmint and lavender oil being recommended.
In the final analysis, you will need to discover what works best for you with the least risk, side effect, cost and inconvenience. If you take any medications, you should understand their adverse effects and carefully follow directions for use. And remember, there is one safe, sure cure: 'Sleep under a tree all day.' "
Hope this gets you started.
DocVikingo
