Post by Ask Jan on May 29, 2011 8:42:25 GMT -8
Motion Sickness-Cannabis as Treatment
Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement. Depending on the cause, it can also be referred to as seasickness, carsickness, simulation sickness or airsickness.
Dizziness, fatigue, and nausea are the most common symptoms of motion sickness. Sopite syndrome in which a person feels fatigue or tiredness (yawning, lack of interest in working) is also associated with motion sickness. Nausea in Greek means seasickness (naus means ship). If the motion causing nausea is not resolved, the sufferer will frequently vomit. Unlike ordinary sickness, vomiting in motion sickness tends not to relieve the nausea. About 33% of people are susceptible to motion sickness even in mild circumstances such as being on a boat in calm water, although nearly 66% of people are susceptible in more severe conditions. Individuals and animals without a functional vestibular system are immune to motion sickness.
Motion sickness on the sea can result from being in the berth of a rolling boat without being able to see the horizon. Sudden jerky movements tend to be worse for provoking motion sickness than slower smooth ones, because they disrupt the fluid balance more. A "corkscrewing" boat will upset more people than one that are gliding smoothly across the oncoming waves. Cars driving rapidly around winding roads or up and down a series of hills will upset more people than cars that are moving over smooth, straight roads. Looking down into one's lap to consult a map or attempting to read a book while a passenger in a car may also bring on motion sickness.
The most common hypothesis for the cause of motion sickness is that it functions as a defense mechanism against neurotoxins. The area postrema in the brain is responsible for inducing vomiting when poisons are detected, and for resolving conflicts between vision and balance. When feeling motion but not seeing it (for example, in a ship with no windows), the inner ear transmits to the brain that it senses motion, but the eyes tell the brain that everything is still. Because of the discordance, the brain will conclude that one of them is hallucinating and further conclude that the hallucination is due to poison ingestion. The brain responds by inducing vomiting, to clear the supposed toxin.
Motion sickness can be divided into three categories:
1. Motion sickness caused by motion that is felt but not seen
2. Motion sickness caused by motion that is seen but not felt
3. Motion sickness caused when both systems detect motion but they do not correspond.
Motion is felt but not seen
In these cases, motion is sensed by the vestibular system and hence the motion is felt, but no motion or little motion is detected by the visual system.
A specific form of motion sickness, carsickness is quite common and often evidenced by the inability to read a map or book during travel. Carsickness results from the sensory conflict arising in the brain from differing sensory inputs. The eyes mostly see the interior of the car, which is motionless while the vestibular system of the inner ear senses motion as the vehicle goes around corners or over hills and even small bumps. Therefore, the effect is worse when looking down but gets better by looking outside of the vehicle
Airsickness is a sensation, induced by air travel. It is a specific form of motion sickness considered a normal response in healthy individuals. Airsickness occurs when the central nervous system receives conflicting messages from the body (including the inner ear, eyes and muscles) affecting balance and equilibrium. It is essentially the same as carsickness but occurs in an airplane. However, some significant differences are that an airplane may bank and tilt sharply and due to the small window sizes, a passenger is likely to see only the stationary interior of the plane. Another factor, while in flight, there is little that can be seen outside of the windows that would indicate motion to the visual system
Seasickness is a form of motion sickness characterized by a feeling of nausea and, in extreme cases, vertigo experienced after spending time on a craft on water. It is, again, essentially the same as carsickness, though the motion of a watercraft tends to be more constant. The rocking motion of the craft or movement while immersed in water typically brings it on. As with airsickness, it can be difficult to visually detect motion even if one looks outside of the boat because water does not offer fixed points with which to visually judge motion. Some people experience carsickness yet they do not experience seasickness.
Rotating devices such as centrifuges used in astronaut training and amusement park rides such as the Rotor and the Gravitron can cause motion sickness in many people. While the interior of the centrifuge does not appear to move, one will experience a sense of movement. In addition, centrifugal can cause the vestibular system to give one the sense that downward is in the direction away from the center of the centrifuge rather than the true downward direction.
Dizziness due to spinning
When one spins and stops suddenly, fluid in the inner ear continues to rotate causing a sense of continued spinning while one's visual system no longer detects motion.
Motion that is seen but not felt
In these cases, motion is detected by the visual system and hence the motion is seen, but no motion or little motion is sensed by the vestibular system. Motion sickness arose in such situation has been referred to as Visually Induced Motion Sickness
Motion sickness due to films and other video
This type of sickness is particularly prevalent when susceptible people are watching films on large screens such as Imax but may also occur in regular format theaters or even when watching TV. For the sake of novelty, IMAX and other panoramic type theaters often show dramatic motions such as flying over a landscape or riding a roller coaster. There is little way to prevent this type of motion sickness except to close one's eyes during such scenes or to avoid such movies. Watching 3-D movies can cause headaches. Those are related to difficulties with the focusing, since the clear part of the screen is the single object and not the whole screen as it would be on a conventional screen. The brain tries to bring up the whole picture and it results in a constant attempt to focus. Obviating the rest of the objects and focusing on the object that is clear prevents that type of ache.
In regular format theaters, an example of a movie that caused motion sickness in many people is The Blair Witch Project. Theater patrons were warned of its possible nauseating affects, cautioning pregnant women in particular. In this case, a camcorder was used to film the movie. As the camera was hand held, the camera was subjected to considerably more motion than the average movie camera.
Home movies, often filmed with a hand-held camera, also tend to cause motion sickness in those that view them. The camera-person rarely notices this during filming since his/her sense of motion matches the motion seen through the camera viewfinder. Those who view the film afterward only see the movement, which may be considerable, without any sense of movement. Using the zoom function seems to contribute to motion sickness as well as zooming is not a normal function of the eye. The use of a tripod or a camcorder with image stabilization technology while filming can minimize this effect.
Simulation sickness, or simulator sickness, is a condition where a person exhibits symptoms similar to motion sickness caused by playing computer/simulation/video games
The most common theory for the cause of simulation sickness is that the illusion of motion created by the virtual world, combined with the absence of motion detected by the inner ear, causes the area postrema in the human brain to infer that one is hallucinating and further conclude that the hallucination is due to poison ingestion. The brain responds by inducing nausea and mass vomiting, to clear the supposed toxin. According to this theory, simulation sickness is just another form of motion sickness.
Motion sickness due to Virtual Reality
Motion sickness due to virtual reality is very similar to simulation sickness and motion sickness due to films. In virtual reality, however, the effect, made more acute, as all external reference points are blocked from vision, the simulated images are 3-dimensional and in some cases stereo sound that may give a sense of motion. The world's most advanced simulator, the NADS-1, located at the National Advanced Driving Simulator is capable of accurately stimulating the vestibular system with a 360-degree horizontal field of view and 16 degree of freedom motion base. Studies have shown that exposure to rotational motions in a virtual environment can cause significant increases in nausea and other symptoms of motion sickness
Space sickness was effectively unknown during the earliest spaceflights, as these were undertaken in very cramped conditions; it seems to be aggravated by being able to freely move around, and so is more common in larger spacecraft. Around 60% of all Space Shuttle astronauts currently experience it on their first flight; the first case is now suspected to be Gherman Titov, in August 1961 onboard Vostok 2, who reported dizziness and nausea. However, the first significant cases were in early Apollo flights; Frank Borman on Apollo 8 and Rusty Schweickart on Apollo 9. Both experienced identifiable and reasonably severe symptoms—in the latter case causing the mission plan to be modified
Motion that is seen and felt but do not correspond
When moving within a rotating reference frame such as in a centrifuge or environment where gravity is simulated with centrifugal force, the Coriolis Effect causes a sense of motion in the vestibular system that does not match the motion that is seen.
Sometimes when riding a vehicle for a long time on a badly maintained road at a very slow (10–20 km/h) speed the two senses fail to correspond. Due to the poor road quality, the vehicle will jerk too much giving a sense of severe motion to the inner ear. However, due to the slow speed the eye does not sense proportional amount of motion
Many cures and preventatives for motion sickness have been proposed.
Acupressure wristbands may help prevent motion sickness. The bands, sold over-the-counter in many drug stores, use a pressure point on the wrist to prevent feelings of nausea associated with carsickness and airsickness.
One common suggestion is to simply look out of the window of the moving vehicle and to gaze toward the horizon in the direction of travel. This helps to re-orient the inner sense of balance by providing a visual reaffirmation of motion.
In the night, or in a ship without windows, it is helpful to simply close one's eyes, or if possible, take a nap. This resolves the input conflict between the eyes and the inner ear. Napping also, helps prevent psychogenic effects (i.e. the effect of sickness being magnified by thinking about it).
A simple method for relieving common and mild carsickness is chewing. Chewing gum has an uncanny effectiveness for reducing carsickness in those affected. Chewing gum, however, is not the only thing one may chew to relieve mild effects of carsickness, snacking on sweets or just chewing in general seems to reduce adverse effects of the conflict between vision and balance.
Fresh, cool air can also relieve motion sickness slightly, although it is likely this is related to avoiding foul odors, which can worsen nausea.
Eating Ginger has also been found to reduce motion sickness. This is available in tablet form or a fresh stem of ginger can also be chewed to relieve symptoms.
Over-the-counter and prescription medications are readily available, such as Dramamine (dimenhydrinate), Stugeron (cinnarizine), and Bonine/Antivert (meclozine).
Scopolamine is effective] and is sometimes used in the form of transdermal patches (1.5 mg) or as a newer tablet form (0.4 mg). A doctor determines the selection of a transdermal patch or scopolamine tablet after consideration of the patient's age, weight, and length of treatment time required.
Interestingly, many pharmacological treatments, which are effective for nausea and vomiting in some medical conditions, may not be effective for motion sickness. For example, metoclopramide and prochlorperazine, although widely used for nausea, are ineffective for motion-sickness prevention and treatment. This is due to the physiology of the CNS vomiting centre and its inputs from the chemoreceptor trigger zone versus the inner ear. Sedating anti-histamine medications such as promethazine work quite well for motion sickness, (although they can cause significant drowsiness).
Ginger root is an effective anti-emetic. One trial review indicated that sucking on crystallized ginger or sipping ginger tea could help to relieve the nausea, while an earlier study indicated that it had only a placebo effect. Tests conducted on the television show s: Myth busters and Food Detectives support the theory that ginger is an effective treatment for the nausea caused by motion sickness.
Ginger calms the pyloric valve located at the base of the stomach. This relaxation of the valve allows the stomach to operate normally whereby the contents will enter the small intestine instead of being retained within the stomach. It is this undesirable effect of retention in the stomach that eventually results in vomiting. Vomiting is not seasickness but is only a symptom or side effect; although the effect most commonly associated with seasickness. This link reports on a ginger study; notice the comment about less vomiting when taking ginger, but not less nausea.
Stugeron is not available in the U.S. either over-the-counter or by prescription. It has been implicated in triggering palsy and has been banned by the FDA
As astronauts frequently have motion sickness, NASA has done extensive research on the causes and treatments for motion sickness. One very promising looking treatment is for the person suffering from motion sickness to wear LCD shutter glasses that create a stroboscopic vision of (4 Hz with a dwell of 10 milliseconds).
Marijuana (Cannabis) as Treatment for Motion Sickness
"The overwhelming preponderance of the evidence in this record establishes that marijuana has a currently accepted medical use in treatment in the United States for nausea and vomiting resulting from chemotherapy treatments in some cancer patients. To conclude otherwise, on this record, would be unreasonable, arbitrary and capricious."
“Opponents of medical marijuana often point to dronabinol, the synthetic version of one of marijuana’s active ingredients that is available in pill form. The use of only one active ingredient makes dronabinol less effective than medical marijuana. Many ailments respond better to a combination of marijuana’s active ingredients rather than just one. In addition, because dronabinol is a pill, it is difficult for people with nausea and vomiting to swallow. Finally, like any medication that is swallowed, dronabinol takes a long time to digest and have its effects. Inhaled marijuana vapors can work markedly faster."
"The anti-emetic properties of cannabis have been studied in humans more widely than any other indication. Nausea and vomiting following chemotherapy was felt to be one of the best supported therapeutic uses of cannabis and cannabinoids by the British Medical Association in their review of 23 studies, and was also supported by the American Institute of Medicine. This indication for cannabis has become common knowledge among patients, was the subject of a popular book, and has received some endorsement amongst American oncologists in a survey study.
A large body of knowledge has now been amassed in this context because of state-sponsored studies. Pooling available data in some 768 patients, oral THC provided 76-88% relief of nausea and vomiting, while smoked cannabis figures supported 70-100% relief in the various surveys.
Thus, an inhalation (but preferably not smoking) cannabinoid drug delivery system would be advantageous for treating chemotherapy-induced nausea...
However, because modern antiemetics probably act through different mechanisms, cannabinoids might be effective in people who respond poorly to currently used antiemetic drugs, or cannabinoids might be more effective in combination.
"I have prescribed Marinol to some of my patients and it has proven effective in some cases. However, scientific and anecdotal reports consistently indicate that smoking marijuana is a therapeutically preferable means of ingestion. Marinol is available in pill form only. Moreover, Marinol contains only one of the many ingredients found in marijuana (THC). It may be that the beneficial effects of THC are increased by the cumulative effect of additional substances found in cannabis. That is an area for future research. For whatever reason, smoking appears to result in faster, more effective relief, and dosage levels are more easily titrated and controlled in some patients."
"A friend then gave me a marijuana cigarette, suggesting that it might help quell my nausea. I took three puffs from the cigarette. One-half hour later, I was calm, my nausea had disappeared, my appetite returned, and I slept that evening.
CANTIMOL is a more potent version [of Canasol] has been developed, but not registered, and the team is ready for clinical trial of a third active ingredient isolated from ganja for the treatment of motion sickness.
CANASOL an ophthalmic drop solution prepared from cannabis sativa that contains 0.3% active solid.
This is also true in AIDS and even in the unsettled stomach common in motion sickness.
“Marijuana is the best agent for control of nausea.”
Pharmaceutical nausea-control drugs come in pills that are often swallowed by the patient only to be thrown back up. Because cannabis is ingested as smoke, it stays in the system and keeps working even if vomiting continues.
Cannannabinoids are used in patients with cachexia, cytotoxic nausea, and vomiting, or in patients who are unresponsive to other agents. These may cause changes in perception, dizziness, and loss of coordination.
Cannabis - Medical marijuana, in the U.S., Schedule I drug.
Dronabinol (Marinol) - Schedule III drug in the U.S.
Some synthetic cannabinoids such as Nabilone (Cesamet) or the JWH series.
Sativex is an oral spray containing THC and CBD. It is currently legal in Canada and a few countries in Europe but not legal in the U.S.
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness
Drs West and Lockhart have also created Canavert, a cannabis based treatment for motion sickness. Available in the West Indies only.
The nausea suppression and mild analgesic effects of cannabis also provide a degree of relief for persons suffering from motion sickness. Nausea and vomiting can occur as a result of a variety of conditions such as acute viral illness (the flu), cancer, cancer chemotherapy or side effects from other medications, radiation treatment, post-operative recovery, pregnancy, motion sickness and poisoning. There is clear evidence-based research that supports the anti-emetic effects of cannabis for persons suffering from nausea and vomiting. The 1999 IOM report, Marijuana and Medicine: Assessing the Science Base, agreed that the evidence supported the anti-emetic effects of cannabis, but expressed concern related to smoking the plant material. While inhalation allows for immediate relief, clinicians should be recommending vaporization rather than smoking to eliminate this concern.
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1. Coutts, A. A., & Izzo, A. A. (2004). The gastrointestinal pharmacology of cannabinoids: an update. Curr Opin Pharmacol, 4(6), 572-579.
2. Pertwee, R. G. (2001b). Cannabinoids and the gastrointestinal tract. Gut, 48(6), 859-867.
3. Massa, F., & Monory, K. (2006). Endocannabinoids and the gastrointestinal tract. J Endocrinol Invest, 29(three Suppl), 47-57.
4. Di Carlo, G., & Izzo, A. A. (2003). Cannabinoids for gastrointestinal diseases: potential therapeutic applications. Expert Opin Investig Drugs, 12(1), 39-49.
5. Dr. West, Dept. of Pharmacology University of West Indies, Mona, Kingston, Jamaica
6. Dr Lockhart: fax (972) 669-8083