Apomorphine is a medication used in dogs primarily to induce vomiting after they’ve swallowed something toxic or dangerous. It’s the most common emetic drug used in veterinary emergency settings, and it works fast, typically triggering vomiting within about one to two minutes when given intravenously.
Why Vets Use Apomorphine
Dogs eat things they shouldn’t. Antifreeze, insecticides, chocolate, medications left on a counter, small objects that could cause a blockage. When a dog swallows something harmful and arrives at the vet quickly enough, the priority is getting it back out before the body absorbs it. That’s where apomorphine comes in.
The drug is a dopamine agonist, meaning it stimulates dopamine receptors in a part of the brain called the chemoreceptor trigger zone. This area acts as the brain’s poison detector, and when apomorphine activates it, the brain sends a strong signal to vomit. The effect is reliable and rapid, which is exactly what you need in a poisoning situation where every minute counts.
Apomorphine is used for two broad categories of emergencies: toxic ingestions (poisons, medications, toxic foods) and foreign material ingestions (objects that could obstruct the digestive tract). Interestingly, flat-faced breeds like bulldogs and pugs are more likely to need it for poisoning specifically, with about 1.6 times greater odds of presenting for toxin ingestion compared to foreign material ingestion.
How It’s Given
Vets can administer apomorphine through several routes, and the choice affects how quickly your dog will start vomiting. Intravenous injection is the fastest, with vomiting starting in roughly two minutes. Subcutaneous injection (under the skin) takes longer, around 13 and a half minutes on average. A third option involves placing a small amount of the drug directly into the conjunctival sac, the pocket inside the lower eyelid, where it absorbs through the mucous membrane.
The IV route is generally preferred in urgent situations because speed matters. In one study comparing apomorphine to a newer drug called ropinirole, dogs given apomorphine vomited at a median time of about one and a half minutes, compared to nearly nine minutes for the alternative. That time difference can be significant when a toxin is being absorbed.
When Apomorphine Should Not Be Used
Inducing vomiting is not always the right call, even when a dog has eaten something dangerous. There are several situations where apomorphine is contraindicated:
- Corrosive substances, hydrocarbons, or petroleum products: These cause chemical burns going down, and vomiting them back up doubles the damage to the esophagus and throat.
- Neurological symptoms: If a dog is already showing signs like stumbling, seizures, extreme hyperactivity, or reduced consciousness, vomiting creates a serious aspiration risk (inhaling vomit into the lungs).
- The dog has already vomited: If the stomach has already emptied somewhat, further forced vomiting adds risk without much benefit.
- Substances with antiemetic properties: Some ingested drugs suppress the vomiting reflex, which can make apomorphine ineffective and complicate the situation.
This is one of the key reasons veterinarians, rather than dog owners, should make the decision about whether to induce vomiting. Owners who attempt to handle it at home are more likely to use incorrect doses, try too many times after a failed attempt, or force vomiting when the substance swallowed makes it unsafe to do so.
Side Effects
Apomorphine’s side effects are generally mild. In one study of 42 dogs, about 14% experienced some kind of adverse effect. The most common were lethargy and persistent nausea after the vomiting stopped. Some dogs drooled excessively. One dog that received the drug in the eye showed reddened eyes afterward. All of these effects resolved on their own without treatment.
More serious complications like bloating, stomach ulcers, or blood in the vomit or stool were not reported in the study. That said, the drug does carry a risk of prolonged vomiting in some dogs, and if that happens, vets can stop it with a dopamine-blocking medication. In rare cases where apomorphine causes significant sedation or depressed breathing, an opioid-reversing agent can counteract those effects. These reversibility options give vets a safety net when using the drug.
Why Not Hydrogen Peroxide?
You may have heard that hydrogen peroxide can also make dogs vomit, and some pet poison hotlines still recommend it as a home first-aid option. Apomorphine is preferred in clinical settings because it works more predictably, acts faster, and its effects can be pharmacologically reversed if something goes wrong. Hydrogen peroxide works by directly irritating the stomach lining, which means it can cause inflammation or damage to the stomach itself, a side effect apomorphine doesn’t share.
Apomorphine Only Works in Dogs
One detail worth knowing: apomorphine is specifically effective in dogs. It does not reliably induce vomiting in cats. Cats lack the same chemoreceptor trigger zone sensitivity to dopamine agonists, so vets use different approaches for feline poisoning emergencies. If you have both dogs and cats, don’t assume the same emergency protocol applies to both species.