Introduction
Nausea and vomiting are common aftereffects of anesthesia and surgery in dogs. The stress of surgery, anesthetic drugs, and pain medications can all trigger nausea that may last for 24 hours or more after the procedure. Though usually mild, post-surgical nausea can be concerning for dog owners and lead to reduced appetite, lethargy, and other problems. Luckily, there are several effective medications vets can prescribe to control nausea. Being aware of the causes, risks, and treatments for post-surgical nausea will help dog owners understand what to expect and how to keep their dogs comfortable during recovery.
Causes of Nausea After Surgery
There are several common causes of nausea in dogs after surgery:
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Anesthesia Side Effects – The drugs used for anesthesia can sometimes cause nausea as a side effect. Anesthetics, even modern ones, can irritate the stomach lining and trigger nausea.
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Pain Medications – Opioid pain medications like morphine can frequently cause nausea. Dogs given opioids for post-surgical pain control are prone to vomiting.
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Handling of Intestines – During abdominal surgery, the intestines are handled and manipulated. This can directly irritate the intestines and stomach, making nausea more likely after surgery.
The combination of anesthesia, pain meds, and intestinal irritation puts dogs at high risk of nausea and vomiting after most major surgeries. Knowing the causes helps veterinarians administer the appropriate anti-nausea medications.
Risks of Post-Surgical Nausea
Nausea after surgery can pose several risks and complications if left untreated. The most concerning risks include:
Dehydration
Frequent vomiting and retching can lead to fluid loss and dehydration. Dogs who are dehydrated have thick saliva, dry gums, sunken eyes, lethargy, and loss of skin elasticity. Dehydration needs to be addressed quickly with supplemental fluids to prevent organ damage.
Aspiration Pneumonia
When a dog vomits, there is a risk that some of the stomach contents can enter the lungs. This can lead to aspiration pneumonia, a serious infection in the lungs. Pneumonia causes breathing difficulties, lethargy, fever, and coughing.
Reduced Appetite and Nutrition
Nausea usually results in reduced appetite in dogs. Not eating properly after surgery slows the healing process and recovery. Lack of nutrition can also cause blood sugar crashes. It’s important to tempt nauseous dogs to eat with bland, enticing foods.
Anti-Nausea Medications
There are several medications that veterinarians commonly prescribe to help prevent and treat nausea in dogs after surgery. The most effective ones include:
Maropitant (Cerenia)
Maropitant is a potent anti-nausea medication often given pre-emptively to dogs before surgery and for a few days after. It blocks receptors in the brain that trigger vomiting and nausea. Maropitant comes as an injectable formulation or oral tablets. It’s effective at preventing vomiting from anesthesia and surgery-related nausea.
Ondansetron
Ondansetron is another anti-nausea medication given before surgery and afterwards. It works by blocking serotonin receptors to prevent nausea and vomiting triggered by surgery, anesthesia, and medications. Ondansetron can be given as an injection or orally. It generally starts working within 30 minutes.
Dolasetron
Dolasetron is similar to ondansetron in its anti-nausea action. It prevents serotonin from binding to receptors that induce vomiting. Dolasetron is given by injection about 30 minutes before anesthesia to prevent vomiting from the anesthesia. It has a long duration of action, working for up to 12 hours.
Metoclopramide
Metoclopramide is sometimes used short-term after surgery to control nausea by speeding up the digestive tract. However, it has more side effects than some newer options, so vets often prefer maropitant or ondansetron now. Metoclopramide is given by injection or orally.
Maropitant (Cerenia)
Maropitant is a common anti-nausea medication given to dogs after surgery. The typical dosage is 1 mg per pound (2.2 mg/kg) given once a day by injection under the skin. It is continued for 1-2 days after surgery.
Maropitant prevents nausea by blocking the body’s dopamine receptors, which control nausea and vomiting. It starts working within about 1 hour after injection and lasts for around 24 hours.
Maropitant is very effective at preventing vomiting from motion sickness as well as post-operative nausea. It has minimal side effects but can occasionally cause pain at the injection site, diarrhea or lethargy.
Overall, maropitant is a safe and effective anti-nausea medication for dogs. When given at the proper dosage and for the recommended duration, it can significantly reduce nausea and vomiting after surgery.
Ondansetron
One of the most commonly used anti-nausea medications for dogs after surgery is ondansetron. Ondansetron is available in both injectable and oral tablet forms. The injectable form is typically given prior to surgery or in the immediate post-op period to provide quick relief from nausea.
The oral tablets can be given at home after surgery. The usual dosage of ondansetron for dogs is 0.5-1 mg per pound (1-2 mg/kg) given 1-2 times per day. Most dogs require only 1-2 days worth of anti-nausea medication after surgery.
Ondansetron begins working within 30 minutes after administration and provides anti-nausea effects for 8-12 hours. It’s generally very safe, with few side effects in dogs. The most common side effect is mild diarrhea in some patients.
Dolasetron
Dolasetron is another anti-nausea medication sometimes used for dogs experiencing nausea after surgery. It works by blocking serotonin receptors in the digestive system that trigger nausea and vomiting.
The typical dosage for dolasetron in dogs is 0.6-1 mg/kg given intravenously or intramuscularly. It’s often administered about 30 minutes before surgery as a preventative measure. The effects of a single dose can last up to 24 hours.
Dolasetron requires a prescription from a veterinarian and is given either as an injection at the vet’s office or as an oral tablet at home. Some of the brand names for dolasetron oral tablets include Anzemet and Dolasetron Mesylate.
Overall, dolasetron can be an effective short-term anti-nausea medication for dogs after surgery. It’s less commonly used than other options like Cerenia or ondansetron, but can be a good alternative if other medications aren’t working well for an individual dog.
Metoclopramide
Metoclopramide is sometimes used to treat nausea in dogs after surgery. It works by speeding up the movement of the digestive system and increasing muscle contractions in the stomach and intestines.
The typical dosage of metoclopramide for dogs is 0.2 to 0.4 mg per pound (0.5 to 1 mg/kg) given by injection under the skin every 8-12 hours. Oral tablets or syrup can also be used at a dosage of 0.5 to 1 mg per pound (1 to 2 mg/kg) every 8-12 hours.
Metoclopramide should be given for 2-3 days after surgery. Extended use beyond 3 days is not recommended as it can cause side effects like restlessness, twitching, and muscle spasms in some dogs.
Metoclopramide should be used cautiously in certain breeds like Collies, Shetland Sheepdogs, and Australian Shepherds, as they can be more prone to side effects. It’s important to follow dosage guidelines and veterinary supervision when using this medication.
Home Remedies
In addition to medications prescribed by a veterinarian, there are some home remedies that may help relieve nausea in dogs after surgery. Some options to try include:
Ginger
Ginger has natural anti-nausea properties and can help settle an upset stomach. Give dogs ginger by adding a small amount of grated fresh ginger root to their food or water. You can also give them ginger supplements or ginger tea made for pets.
Peppermint
Peppermint has a calming effect on digestion and can help relieve nausea. Put a few drops of peppermint essential oil on your dog’s collar or bandana to allow them to smell it. You can also make peppermint tea or add peppermint leaves to their food.
Acupuncture
Acupuncture involves stimulating specific points on the body to relieve pain and nausea. Have a licensed veterinary acupuncturist perform acupuncture on dogs after surgery to help control nausea. It should be done gently and carefully to avoid irritating surgical sites.
Always consult your veterinarian before giving any new supplements, herbs, or home remedies to your dog. Only use remedies that are known to be safe for canine use. Monitor your dog closely and discontinue anything that seems to make their nausea worse.
When to See a Vet
If your dog’s nausea persists beyond 24-48 hours after surgery, it’s important to follow up with your veterinarian. Post-surgical nausea that lasts more than a couple of days could indicate an underlying complication or problem.
You should also monitor your dog closely and watch for any signs of dehydration after surgery, like dry gums, sunken eyes, weakness, or excessive thirst. Dehydration needs to be addressed quickly in dogs and can occur if the nausea and vomiting is severe.
In addition to persistent nausea and vomiting, other concerning symptoms to watch for include:
- Loss of appetite
- Lethargy or fatigue
- Abdominal pain or tenderness
- Diarrhea
- Difficulty urinating or defecating
- Fever
- Bloody vomit or stools
If you notice any of these symptoms along with ongoing nausea, contact your vet right away. Your dog may need additional medications, IV fluids, or further treatment to manage their condition and promote healing after surgery.