Here you go guys, and gals. Reproduced from my $500/year online medical textbook. Underlining in the text is my emphasis to higlight what I feel are the more salient points. (or is it SAIL-ent points
Oh, and BTW for those thinking of cutting trans-dermal medications... DON'T CUT THE PATCH!
My recommendations are as follows:
1. If you know you get seasick badly and you're going offshore, try scopalamine on land. If it works, use that, but you must start it before you get on the boat and only use it for 3 days. It's what NASA gives its austranauts.
2. If you can't tolerate scopalamine or don't get seasickness really bad, or are only going out for the day, use meclizine or bonine. Take it before you go on the boat, or before a storm, or before offshore, or generally before the situation that makes you get sick.
3. If you don't often get seasick but sometimes get it bad, keep promethazine + caffeine aboard and use it after you get sick.
4. Accupuncture and ginger are harmless and may be effective but don't rely on them if you have a critical role and know that you're prone to bad seasickness.
TREATMENT AND PREVENTION
A number of interventions can be used to prevent or alleviate motion sickness . Treatments may be more effective when used for prevention rather than after symptoms have developed.
Since conflicting sensory cues are believed to induce the symptoms of motion sickness, a straightforward treatment approach is to minimize the discrepancy between these cues. If visual and vestibular information are congruent, motion sickness is less likely to occur.
Labyrinthine cues cannot be readily manipulated, so this approach is based on providing visual information that contains equivalent motion information to that sensed by the vestibular system. Since the labyrinth senses motion in an inertial (earth-fixed) reference frame, this can be accomplished by viewing an earth-fixed environment during motion rather than a head-fixed environment. As an example, motion sickness on a ship is reduced if passengers view the horizon or land masses from the deck rather than their cabin. Similarly, passengers in a car should sit in the front seat and look through the window rather than sitting in the rear and focusing on an object moving with the interior of the car (such as a book).
Motion sickness does not occur during self-generated movements under normal conditions, so a second way to reduce the susceptibility to these symptoms is to control the motion of the vehicle. The driver of a car is less prone to motion sickness than a passenger, presumably because the driver's brain can utilize the motor commands related to controlling the car to predict in an approximate manner the motion of the head.
Drug therapies can be used to suppress conflicting sensory cues in the brain regions that process afferent signals or to treat nausea. In general, the effectiveness of medications depends upon inhibition of activity in the vestibular nuclei, where labyrinthine and visual sensory cues are combined and synthesized. Drugs that reduce activity in the vestibular nuclei include antihistamines, anticholinergics, and benzodiazepines; other medications that reduce motion sickness include antidopaminergics and sympathomimetics (table 1) [15,35].
In general, medications should be taken before passive motion begins, since they are less effective in relieving symptoms that have already developed.
A number of antihistamines can be used to treat motion sickness,
and their effect is probably related to their anticholinergic effects . Medications include dimenhydrinate (Dramamine), diphenhydramine, chlorpheniramine , meclizine, cyclizine, and cinnarizine . Dimenhydrinate is available as a chewable tablet. Cinnarizine is not available in the United States, but is widely used in other countries.
Side effects are mainly related to anticholinergic effects and can include sedation, blurred vision, mouth dryness, and, in the elderly, confusion and urinary retention. One small study suggested that cyclizine may be less sedating than dimenhydrinate at a dose that is equally effective for symptoms of motion sickness .
Nonsedating antihistamines do not appear to be effective for the treatment of motion sickness [39,40].
Scopolamine is commonly used for the management of motion sickness. A systematic review of randomized trials concluded that scopolamine is effective for prevention of motion sickness, but that no trials had examined its effectiveness in treating established motion sickness
, and that the evidence comparing scopolamine with other treatments was inadequate .
At least three randomized trials were performed after the systematic review:
In a trial of experimentally induced motion sickness in 75 patients, scopolamine was more effective in preventing motion sickness than promethazine, meclizine, and lorazepam .
In a trial of the prevention of seasickness in 76 naval crew members, scopolamine was more effective than cinnarizine, an antihistamine . Although differences were marginally significant, scopolamine was associated with fewer adverse effects than cinnarizine.
In a trial of preventing motion sickness in 64 helicopter passengers, the combination of promethazine and caffeine appeared to be more effective than scopolamine alone
Scopolamine is most commonly administered as a transdermal patch applied every 72 hours. Side effects include those discussed above (sedation, blurred vision, mouth dryness, and, in older adults, confusion and urinary retention), and scopolamine is contraindicated in people at risk for angle closure glaucoma. Some instances of poor clinical response to scopolamine patches may be due to inadequate transdermal absorption leading to inappropriately low scopolamine levels in the blood .
Promethazine can be used both for prevention and treatment of motion sickness
[15,45]. In two trials of the prevention of motion sickness cited above, promethazine appeared to be less effective than scopolamine but more effective than meclizine or lorazepam , and promethazine and caffeine appeared to be more effective than scopolamine .
Metoclopramide has also been used for motion sickness, but there is somewhat less evidence for its efficacy than that of promethazine [46,47].
Side effects of antidopaminergics include sedation and extrapyramidal effects.
Ephedrine and amphetamines have been used both to treat motion sickness and to counteract the sedating effects of other medications . (See 'Effect on performance' below.) Ephedrine may have some benefit even after symptoms have developed . Amphetamines are controlled substances with potentially significant side effects and the potential for addiction. Although less studied, pseudoephedrine is readily available in the United States including in combination medications with sedating antihistamines.
Caffeine may also be of benefit when used in combination with other medications.
A randomized trial in 64 patients examined the effects of promethazine 25 mg plus caffeine 200 mg, meclizine 25 mg, scopolamine patch 1.5 mg, and an acustimulation wristband . Only the combination of promethazine and caffeine produced a significant decrease in symptoms; the combination also improved reaction times.
Benzodiazepines may be of some benefit for motion sickness, but they are sedating .
Standard antiemetics such as prochlorperazine or ondansetron can relieve nausea, which is usually the most prominent symptom of motion sickness
. However, in two studies in highly susceptible subjects, one in a laboratory model of simulated rotation and one at sea, ondansetron was ineffective in preventing motion sickness [50,51]. (See "Migrainous vertigo", section on 'Treatment'.)
GABA agonists such as baclofen or gabapentin inhibit the "velocity storage" mechanism in the central vestibular system that may be specifically responsible for producing motion sickness. The utility of these drugs has not been extensively studied to date and their potential usefulness is currently based on results from experiments that use complex movements to induce motion sickness and on case reports [10,11].
Effect on performance Treating motion sickness can be a particular problem in patients who need to perform tasks such as flying a plane or acting as crew on a ship, since most of the medications used are sedating
Dimenhydrinate (Dramamine U.S.) may have particularly negative effects on performance
. A controlled trial of medications for experimental motion sickness in 67 adults suggested that, at clinically useful doses, the drugs had the following order from best to worst for cognitive side effects: meclizine, scopolamine, promethazine, lorazepam
One trial found that administering amphetamine, but not pseudoephedrine, with promethazine appeared to prevent the sleepiness and impairment of psychomotor performance seen with promethazine alone . Another trial found that ephedrine decreased sleepiness and improved performance in patients administered chlorpheniramine, although it did not add to the effectiveness of chlorpheniramine in treating motion sickness .
Treatment in pregnancy
As mentioned above, pregnant women may be particularly susceptible to motion sickness. Medications that are felt to be safe for the treatment of morning sickness can also be used for motion sickness. These include the antihistamines (meclizine, diphenhydramine, and dimenhydrinate), and prochlorperazine, which is listed as category C in pregnancy by the US Food and Drug Administration (FDA) (table 2). (See "Clinical features and evaluation of nausea and vomiting of pregnancy".)
As discussed above, the vestibular response to head motion can decline over time (habituate), if a given motion pattern is presented repetitively. For this reason, physical therapy approaches that utilize recurrent head movements and associated visual cues can sometimes reduce the sensitivity to motion sickness in subjects who are particularly prone to this problem.
Ginger has been used as an alternative medicine to prevent motion sickness. Randomized trials both in experimental motion sickness and in naval cadets at sea have found benefit with pretreatment with one to two grams of ginger
[58,59]. The mechanism of benefit with ginger appears to be related to its effects on gastric motility rather than the vestibular system [60,61].
Acupressure Pressure at the P6 acupressure point on the anterior wrist (three fingerbreadths proximal to the proximal wrist fold, between the palmaris longus and flexor carpi radialis tendons) (picture 1) either by manual pressure or with a wrist band has been reported to be effective for motion sickness in some [62-64], but not all [65-67], controlled trials. A randomized trial with a device that applies electrical stimulation to the P6 point found no benefit .
While these results raise the possibility that acupressure may be of benefit for motion sickness, trials of this sort can be difficult to perform with adequate blinding and allocation concealment. It remains uncertain whether acupressure is effective.
Magnets Although sometimes promoted for this use, we know of no studies evaluating the efficacy of magnets in the treatment of motion sickness.
Nicotine deprivation One small observational study found that overnight nicotine deprivation in smokers resulted in a reduction in motion sickness susceptibility
. The effect was most pronounced in subjects who were heavy smokers and with mild to moderate susceptibility to motion sickness
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