Vets may prescribe meclizine for dogs who suffer from car sickness or vestibular disease (i.e. vertigo). Integrative veterinarian Dr. Julie Buzby explains how this human motion sickness medication can help your dog feel less nauseous. Plus, she reviews the dosing information, discusses the side effects and contraindications, and compares meclizine to other similar medications.
If you suffer from motion sickness, you know that feeling nauseous in the car is awful. And if you have a dog, you may be well aware of the fact that dogs can suffer from motion sickness too. But what you may not know is that there are medications that can treat or prevent car sickness in dogs, just like there are in people.
For example, meclizine, the active ingredient in human motion sickness medications like Antivert®, Simply Motion®, Bonine®, and Travel Sickness®, also works well for dogs. In fact, meclizine is one of my favorite medications for nausea and motion sickness in dogs and cats.
What is meclizine for dogs?
The medication meclizine HCl is an antihistamine that has anticholinergic, anti-emetic, and central nervous system (CNS) depressant actions. In other words, it blocks the action of several signaling molecules (histamine and acetylcholine), helps prevent vomiting, and “slows down” the brain.
Although the exact mechanism isn’t well understood, meclizine seems to be able to keep the brain from relaying messages from the vestibular system (i.e. the structures that give the brain information about the position and motion of the body and head) to the area of the brain that causes nausea, vomiting, and dizziness. This is very helpful in cases of vestibular disease or motion sickness.
What is meclizine used for in dogs?
You see, motion sickness and vestibular disease in dogs (i.e. doggie vertigo) both occur when a dog’s vestibular system (which is located inside the inner ear) becomes over-stimulated or sends inappropriate signals to the brain. Another way of looking at it is that the eyes, ears, and brain aren’t properly communicating to detect motion. This can lead to dizziness and a feeling of instability and nausea.
Since meclizine can interrupt the signal from the vestibular system to the portion of the brain that controls vomiting, it is no surprise that meclizine is useful for preventing nausea and vomiting associated with motion sickness. Plus, vets can also use it to treat nausea and dizziness associated with vestibular disease (i.e. old dog syndrome).
Signs of nausea in dogs
Sometimes it is fairly obvious that your dog is nauseous because he or she suddenly vomits. But other times, nausea can be a bit more subtle. A nauseous dog may exhibit symptoms such as:
- Retching or gagging
- Excessive drooling or licking the lips
- Walking with tail tucked and back arched
- Decreased appetite
- Shaking or trembling
- Appearing anxious or uncomfortable
If your dog is showing these signs in the car, he or she may suffer from motion sickness. While not an emergency, your dog (and your car interior) would probably appreciate it if you had a conversation with your vet about whether meclizine (or another medication) can help your dog’s car sickness.
On the other hand, if your dog is showing those signs seemingly out of the blue, and is also circling, being a wobbly and off-balance dog, or experiencing rapid repetitive eye movements (i.e. nystagmus), he or she may have vestibular disease. In this case, you should make an appointment with your vet immediately. That way he or she can differentiate vestibular disease from a stroke in dogs or other problems, and make a plan to get your dog feeling better.
What is the meclizine dosage for dogs?
After examining your dog, your veterinarian will help decide if meclizine is the right choice. If so, he or she will go over dosage instructions and how to give your dog meclizine.
As discussed, meclizine is a human drug that vets can safely use “off-label” in dogs or cats. It is available over the counter, but some forms might contain other drugs or ingredients that aren’t safe for dogs. Therefore, your veterinarian will typically give you a prescription for meclizine or very specific instructions about what to purchase and how to give it to your dog.
The instructions on the prescription will include:
- Whether your dog needs 12.5 mg or 25 mg meclizine tablets
- The number of tablets to give your dog by mouth
- How often to give your dog the meclizine
- Any relevant precautions or other instructions
Your vet will determine the exact meclizine dose based on your dog’s size and the reason your dog is taking meclizine.
Giving your dog meclizine for motion sickness
If the goal is to reduce your dog’s car sickness, your vet may give you the following guidelines:
- Give your dog the meclizine about 30 to 60 minutes before travel
- Expect the anti-nausea effects to last three to six hours
- You can give the meclizine with or without food. (Giving it with food is a good tactic for dogs who won’t take pills, but remember that for many dogs who develop car sickness, it is best to avoid large meals before traveling.)
Typically, dogs who get car sick while traveling can safely take meclizine long-term (especially since most dogs aren’t taking it every day).
Giving your dog meclizine for vestibular disease
If your dog is taking meclizine for vestibular disease, you will likely be giving the medication daily. Your vet will tell you how often you can give your dog meclizine—usually either once or twice a day. Plus, your vet will instruct you about how long to give the meclizine for your dog’s vertigo. Sometimes your dog will only need meclizine for a short time. But in other situations, your dog may end up being on meclizine long-term.
What to do about missed doses
If you accidentally miss administering a dose of meclizine to your dog, give the prescribed dose as soon as you remember. Then, wait the proper amount of time between the doses before you give the next. Or, if you remember a dose was missed close to the time when your dog would normally receive a dose, just wait until the next dose is due.
As always, if you are unsure what to do, please call your veterinarian. Never give your dog two doses at once because it could put your dog at increased risk for potential side effects or a meclizine overdose.
What are the side effects of meclizine?
However, even at proper dosages, meclizine for dogs can occasionally cause side effects. Some of the possible adverse effects include:
- Increased sleepiness or drowsiness
- Dry gums
- Increased heart rate
- Dry eyes
If your dog experiences any of these side effects, please stop giving the medication immediately. And contact your veterinarian or a nearby emergency clinic for further instructions. Most side effects will wear off in 24 hours, but it is best to consult your veterinarian any time your dog has an abnormal reaction to a medication.
In cases of a meclizine overdose, your dog is likely to show the side effects mentioned above. Plus, sometimes an overdose may result in more serious symptoms like seizures in dogs or respiratory depression. If your dog accidentally gets into meclizine or receives an overdose, please contact your veterinarian or make an emergency vet visit immediately.
Are there dogs who can’t take meclizine?
If your dog experiences any side effects, meclizine may not be the best medication choice for him or her. Additionally, there are some other situations where meclizine may be contraindicated or should be used with caution. They include:
- Pregnant dogs (meclizine caused birth defects in laboratory animals)
- Nursing dogs (may reduce milk supply)
- Enlarged prostate in dogs
- Dogs with spinal disease who are having trouble urinating
- Severe heart disease in dogs
- Dogs who are taking fluoxetine (Prozac®), metoclopramide, cisapride for dogs, or other antihistamines, tricyclic antidepressants, or sedatives
- Bladder cancer in dogs or urinary obstruction
- Glaucoma in dogs
- Liver disease in dogs (blood levels of meclizine may be higher due to decreased breakdown by the liver)
- Dogs who are undergoing allergy testing (since meclizine is an antihistamine it may interfere with test results.)
- GI obstruction
- Seizure disorders
Before you start your dog on meclizine on your own (or any other medication), please consult your veterinarian to make sure it is a safe choice for your dog. Also, ensure that you tell your vet about any medications or supplements your dog is currently taking.
Dramamine and other alternatives to meclizine
If your vet determines meclizine is contraindicated or thinks a different medication may work better for your dog’s situation, he or she will talk to you about some other options. They may include:
The drug dimenhydrinate is the active ingredient in the original formulation of Dramamine. However, there is also a Dramamine® All Day Less Drowsy, which actually has meclizine as the active ingredient. And Dramamine® Non-Drowsy contains ginger as the anti-nausea agent. Thus, all versions of Dramamine are not the same. For the purposes of this discussion, we will talk about the original Dramamine (i.e. the one that contains dimenhydrinate).
The dimenhydrinate version of Dramamine is an antihistamine that acts very similarly to Benadryl for dogs or meclizine. By reducing the brain’s activity and targeting the signals that cause nausea, it can help reduce nausea from car sickness or vertigo.
Dimenhydrinate is safe for dogs but tends to have more sedative properties than meclizine. Sometimes this is ok if you want your dog to sleep the drive away. But other times you may want something that allows your dog to remain more alert. This may make meclizine or Cerenia a better choice. Additionally, dimenhydrinate is also less effective than meclizine in some cases.
Cerenia for dogs (i.e. maropitant citrate) is another common anti-nausea medication for dogs. In fact, it is the first FDA-approved veterinary anti-emetic (i.e. drug to prevent or treat vomiting). Like meclizine, it works by blocking signal transmission in the brain. More specifically, Cerenia prevents substance P from binding to the NK-1 receptors that are responsible for making the dog vomit.
I love Cerenia and recommend it often to my patients. It is highly effective and does not cause sedation. However, Cerenia can take longer than meclizine to work (up to one to two hours). Also, Cerenia tends to be avoided in patients with liver disease. In some cases, though, these dogs may still be able to safely take meclizine.
Ask your vet about meclizine
As you have discovered, meclizine has many benefits for dogs who frequently get car sick or have vertigo from vestibular disease. It is generally safe and well tolerated, takes effect quickly, and works well for many dogs.
If you think your dog might be feeling nauseous, please make an appointment with your vet. Feeling sick and nauseous isn’t fun for anyone. But if the cause is motion sickness or vestibular disease, meclizine might be the perfect solution for you and your furry friend!
Has your dog taken meclizine?
Please share your experiences below.