August 2021

In this VETgirl online veterinary continuing education blog, Amy Newfield, CVT, VTS (ECC) reviews motion sickness in veterinary medicine, and what you can do to increase the human-animal bond by treating it!

Motion sickness: Increasing the pet/owner bond

Amy Newfield, MS, CVT, VTS (ECC)

An estimated 15% of all dogs suffer from true motion sickness. There are many causes of vomiting in the dog, however true motion sickness is hallmarked when the dog vomits only when the car is moving. Once the car stops moving the dog should stop vomiting. A poll performed in 2009 found that 92% of veterinarians/technicians felt that motion sickness had a moderate to significant impact on a dog owner’s quality of life with that dog and 89% felt it had a moderate to significant impact on the pet-owner bond. Motion sick dogs are left home more frequently. How can we help the pet/owner bond?

EARLY INTERVENTION
There are many simple things owners can do at home to help set their dog up for success. First, it is important that any dog suspected of having motion sickness should not be fed at least a couple hours prior to the trip. For some dogs that have specific factors that cause motion sickness, simply allowing fresh air or allowing the dog to stand may help alleviate the motion sickness. This is particularly true in the case of puppies who tend to be either fearful or motion sick more frequently than older dogs.

All puppies and adult dogs that are fearful should be slowly desensitized to the car (or boat) by first allowing them in the car for “fun” time without it moving. Eventually the car should be turned on while the owner offers a couple of treats or the dog’s favorite toy. The owner should then drive for 30 seconds and stop and reward the behavior. Eventually the time in the car is increased so the pet associates the car with being in a fun place. During this time, it is important that the owner teaches the puppy what is appropriate car riding etiquette (not jumping up or running around). If, at any point, the dog shows signs of fear or nausea the training should be stopped and resumed at a point the dog can tolerate. Appropriate desensitization takes many weeks to months and occurs so slowly that the dog barely notices a change. This systematic desensitization works well for any puppy or dog who vomits because of anxiety or fear. Behavior modification using systematic desensitization will likely not help a vestibular issue.

PREVENT THE VOMIT
When dealing with a truly motion sick dog, owners have both pharmaceutical and alternative medicine options. Each motion sick dog is different and what may work for one dog may not work for another.

PHARMACEUTICAL OPTIONS
Below are some of the most common medications currently used to treat motion sickness in dogs.

Dimenhydrinate (Dramamine®) and Diphenhydramine (Benadryl®):
Both dimenhydrinate and diphenhydramine are antihistamines that block the histaminic (H1) receptor of the vomiting center. It has been suggested that when exclusively using an H1-histamine blocking agent, a second treatment should be added, combining a M1-cholinergic receptor blocker to obtain control of emetic signals originating from the vestibular apparatus. Dimenhydrinate is close in nature to diphenhydramine because it contains 54% diphenhydramine. The most common adverse reactions seen in many antihistamines are central nervous system (CNS) depression (sedation) and anticholinergic effects (dry mouth, urinary retention). Less commonly, diarrhea, vomiting and anorexia can occur. Antihistamines are not recommended for use in pregnant dogs. It is recommended to administer these medications about 30 minutes before the car ride, and the effects last 3-6 hours.

Meclizine (Bonine®):
Meclizine is also an antihistamine, but very little information is available regarding its use in dogs. It is primarily used as an antihistamine and to treat motion sickness. While no studies have been done looking at the effects on pregnant dogs, it is reportedly the first drug of choice for vomiting associated with pregnancy in women because it is thought to cause less toxic effects on the fetuses. The exact mechanism of action for the prevention of motion sickness is not understood. Sedation has been reported as the most common side effect noted.

Maropitant (Cerenia®):
In 2007 Pfizer released a new drug, maropitant citrate (Cerenia®) into the market for the treatment and prevention of acute vomiting and the prevention of vomiting due to motion sickness. Cerenia® became the first FDA drug approved for preventing the vomiting associated with motion sickness in dogs.

Maropitant works by blocking the action of substance P, found in the highest concentration in the emetic center. Substance P is a neuropeptide which helps regulate mood, anxiety, stress, respiratory rhythm, pain, nausea and vomiting. The receptor for substance P is NK1. NK1 receptors are found in both the CRTZ and the emetic center. When substance P binds to the NK1 receptor vomiting occurs. By blocking the binding of substance P to NK1 receptors, vomiting stimuli is interrupted. Several studies in dogs have shown that blocking substance P from its NK1 receptor is very effective in preventing vomiting due to motion sickness. In a study of 122 dogs with a history of motion sickness dosed two hours prior to travel, only 7% vomited after being administered maropitant as opposed to 55% vomiting after receiving placebo. Side effects were similar between both treatment groups.

A higher dose than that of the acute vomiting dose is needed in order for maropitant to be effective in preventing vomiting due to motion sickness (8mg/kg orally). Maropitant only needs to be administered once per day, which is very convenient for owners, but it cannot be used for more than two days in a row and should only be used in dogs older than 16 weeks of age. In order for the best results to occur, pets must be fasted one hour before the dose is given. Approximately two hours before the car ride, the pet should be given the oral dose of Cerenia® in a small amount of food such as deli meat or peanut butter. Studies have shown it takes one to two hours for maropitant to take effect. In the event that an owner has an unexpected car ride maropitant may still be effective if given only one hour prior to the ride. Many dogs dosed one hour prior to travel, (86%) in a clinical trial, did not vomit.

The most common side effect was hypersalivation, which affected approximately 12% of the dogs in the study. Unlike most other drugs used to help prevent motion sickness, maropitant does not cause sedation. It is not currently approved for use in pregnant or lactating dogs.

ALTERNATIVE OPTIONS
Alternative medicine can be controversial because of the lack of controlled research studies. Despite the limited scientific published studies available, alternative medicine remains very popular in both human and veterinary medicine.

Acupuncture/Acupressure:
It has been suggested that both acupressure and acupuncture may help with motion sickness; however, their efficacy is unknown. There have been more studies in humans showing the benefit of acupuncture versus the benefits of acupressure. The acu-point most commonly used is Pericardium 6 (P6) and is located on the inside of the wrist, about two inches above the center of the wrist crease. This is why many travel stores sell wrist bands with small “buttons” that are designed to apply continuous pressure to the P6 point. While it is widely known in humans that acupressure and acupuncture can help with motion sickness, there is still some question regarding dogs. For many owners acupuncture is simply not an option because of the expense. To date, there has been no positive research with the use of wrist bands or other continuous acupressure treatment methods in dogs.

Ginger:
For years there has been much positive research showing that ginger may be effective in dealing with motion sickness in humans. Several studies have shown a reduction in motion sickness when ginger was used. Unfortunately, a National Aeronautics and Space Administration sponsored study at the Louisiana State University in 1984 concluded that ginger, given two hours before the motion event, did not help reduce signs of motion sickness. The use of ginger appears to have some benefit in veterinary medicine as well, but how efficacious it is remains to be unknown. It does appear that, in order for any effectiveness to occur, ginger extracts must be administered as opposed to products that contain some ginger (ginger snap cookies, ginger ale).

Other Natural Herbs: Panax ginseng, black horehound, chamomile, fringe tree, peppermint, meadowsweet and lemon balm may help with nausea as well. Their efficacy is still debated and there is little to no published information regarding their safe and effective use in dogs.

Unfortunately, for most motion sick dogs alternative medicine options simply do not work. Owners are left to try pharmaceutical treatment or simply choose to leave their dog home.

YOUR ROLE TO INCREASE THE PET/OWNER BOND
Ask the owner about it! Ask, “How does Fluffy like the car?” This question will get owners to share with you the stories of fear, vomit or even aggression about riding in the car. Often times owners feel like there is nothing that can be done for their dog. They may have already tried some treatment options and found them not to work. They may be unaware that new medications and options have become available.

If a puppy is experiencing motion sickness it is important to speak to the owner about systematic desensitization to avoid a learned fear of the car later in life. Many times owners assume their new puppy will simply grow out of motion sickness. While this sometimes is true, without early intervention and treatment, motion sickness and fear may become worse.

With the summer approaching, owners will start making vacation plans. Many owners may opt to leave car-sick Fido at home unless his motion sickness can be cured. As a veterinary professional you have the ability to speak to owners about this syndrome and make a difference for them.

  1. It seems that no food before the travel is recommended. This is a problem for the drive home after puppy class.

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