The side effects of deworming a dog are gastrointestinal issues mostly.

Other side effects include lethargy, behavioral changes, or mild allergic reactions.

This drug helps get rid of parasites.

They are usually pills and given orally.

Parasites are a dangerous threat to your dog’s health.

The medication needs to be taken as early as 2 weeks.

As with any medication, anthelmintics can have side effects.

Let’s learn how to deal with them.

Common Side Effects of Deworming a Dog

  • Addressing Dog Owners’ Worries
  • Reassuring the Safety of Deworming Medications
  • Importance of Proper Dosage

Addressing Dog Owners’ Worries

Deworming is a necessary step in your dog’s life, especially if it’s a puppy.

By deworming, you’re protecting them. [1]

While going on walks, especially without a leash, your dog can sniff and eat many things.

Sometimes that thing can be contaminated with a parasite.

Parasites live in all organic matter, from feces to plants.

This means your dog can easily come in contact with them. [2]

Reassuring the Safety of Deworming Medications

Even with side effects deworming medication is safe.

The same side effects can be seen in vaccines in humans, and we know they’re safe.

Deworming medications are safer than having a parasite.

Bad side effects last longer and are far worse if your dog contracts a parasite.

Antiparasitics are bad only if you’re a worm in a body.

Importance of Proper Dosage

The doses of antiparasitics vary based on a few factors.

The first factor is the type of parasite you are dealing with.

There are different drugs for different parasites.

Parasites can be classified into two main groups- ectoparasites and endoparasites.

Ectoparasites live on the outside of the body.

Endoparasites live inside the body, entering from the mouth.

They’re called intestinal worms.  

They can also spread into different organs and tissues. [3]

The doses for ectoparasites are usually larger.

The substances used for ectoparasites can be toxic and deadly if ingested.

Lower doses should be applied to dogs with kidney problems.

The antiparasitics are usually excreted through urine, meaning they go through the kidneys.

If the kidneys don’t work properly, the drug can return and stay in the bloodstream longer.

A weak immune system is also a sign to reschedule the application.

Overdosing on an antiparasitic can lead to kidney problems as well.

This happens even if there wasn’t a medication problem before.

It causes vision and hearing loss too.

In high enough doses, it can cause nerve damage as well.

Identifying Typical Side Effects

  • Common Side Effects
  • Gastrointestinal Disturbances
  • Lethargy or Behavioral Changes
  • Mild Allergic Reactions

Common Side Effects

Effects Frequency Duration
Drooling Very frequent A few hours to a day
Vomiting Frequent A few hours to a day
Diarrhea Very frequent Until all parasites are out of the intestine, maybe a few days more
Dead worms in stool Rarely not present/ almost always Until all parasites are out of the intestine
Lethargy Very frequent A few hours to a day
Mild allergic reactions Rare Until antihistamine and corticosteroids are applied
Anaphylaxis Very rare Until antihistamine and corticosteroids are applied

The side effects of deworming can be worrying.

But the side effects of deworming a dog are easier and quicker to pass than the ones from a parasite.

Your pet might vomit and not have an appetite.

The medications can also cause an upset stomach.

Some antiparasitics are applied and can cause local reactions like an allergy.

The symptoms resolve on their own after a while.

An extremely rare occurrence is neurological symptoms from neuro toxicosis.

If your dog has a seizure, call your veterinarian immediately.

Leading up to the seizure can be tremors and dilated pupils. [4]

Gastrointestinal Disturbances

This is a normal symptom after antiparasitics.

Intestinal and gut symptoms are the most common after applying antiparasitics.

The most noticeable is drooling.

Dogs and humans can drool when they feel sick.

Vomiting is the next gastrointestinal disturbance.

Diarrhea is also present.

This is because the antiparasitic is trying to get rid of all the parasites in the intestine.

The fastest and easiest way is through defecating.

Both these side effects can lead to dehydration if they last longer than a day.

Most of the time, you can see dead worms in their poop after a few days.

This means the deworming treatment worked.

Most of the parasites that cause problems are in the gastrointestinal system.

Only a few parasites that can be found in a pup reside in other systems and organs.

Hookworm is a good example of this.

They cause intestinal inflammation.

They can also lead to dangerously low red blood cell counts. [5]

Lethargy or Behavioral Changes

Lack of energy can be seen in most dogs.

If the symptoms are more severe, they’ll want to rest.

If this is a symptom, a lack of reaction when called or thrown a toy can be seen too.

Chronic cases of whipworms lead to these symptoms.

They also cause bloody diarrhea and weight loss.

If this goes on for longer than a day, contact your vet.

Mild Allergic Reactions

Very rarely, anthelmintics can cause an allergic reaction in your pet.

You may see your dog drooling and itching.

That might be a sign of it.

If the symptoms are persistent, seek veterinary care immediately.

Without treatment, this can lead to anaphylaxis.

Assessing Severity and Urgency

  • Signs Requiring Veterinary Attention
  • Severe or Persistent Gastrointestinal Distress
  • Allergic Reactions or Difficulty Breathing
  • Unusual or Severe Behavioral Changes

Signs Requiring Veterinary Attention

Any signs that last more than a day should lead to a vet call.

Severe signs should call for immediate professional attention.

Tremors and foaming can lead to seizures.

A more obvious sign of overdosing is also dilated pupils.

Live worms in feces after a few days mean that the antiparasitic either didn’t work or was in a low dose.

Bloody diarrhea and vomiting after a few days can indicate the same.

If blood is present, the parasites have done severe damage.

Severe or Persistent Gastrointestinal Distress

A lack of interest in food can be a sign that your dog is in pain.

This can also lead to tremors and persistent blood in the stool.

The feces may also be more liquid and have a gel surrounding it. [6]

The discomfort can also lead to gagging and vomiting.

Swelling in the stomach is very visible in puppies that haven’t been dewormed.

Allergic Reactions or Difficulty Breathing

Allergic reactions are rare but can happen.

Heavy breathing may be one symptom.

Heavy breathing can be caused by pain and discomfort as well.

Either way, it’s best to consult with a vet.

They might tell you to bring your pet.

After assessing the situation, if it’s an allergy, they’ll treat it.

Unusual or Severe Behavioral Changes

After deworming, lethargy is usual.

Unwillingness to move is not.

If your dog refuses to move and whines, it might be in severe pain.

Another unusual behavior is hyperactivity.

Dogs bark, whine, and can become aggressive.

In these cases, it’s recommended to change the prescription. [7]

Managing Side Effects and Alleviating Discomfort

  • Recommendations for Mild Side Effects
  • Bland Diet Options
  • Hydration Monitoring
  • Gentle Exercise and Mental Stimulation

Recommendations for Mild Side Effects

Side effects are normal after deworming.

Keep your dog company and give it extra love.

It might be in pain and in need of comfort.

Give it encouraging words and try to take their mind off the pain.

Engage them in games.

If they’re willing, take them on a walk.

Bland Diet Options

After deworming, intestinal irritation is normal.

Even if deworming is done on time, some worms may have already done damage.

The antiparasitics can also irritate the lining.

After deworming, it’s important to give your dog very mild and bland food.

The portions should be small.

Boiled chicken meat and rice is the best option at this time. [8]

Hydration Monitoring

In cases of prolonged vomiting and diarrhea, the dogs can dehydrate.

Try to give your dog water in a bowl or with a syringe.

If they don’t want to drink, it’s important to bring your dog to the vet before they fall into shock.

The vet will administer an IV fluid.

After stabilization, they will take care of the rest of the symptoms.

Gentle Exercise and Mental Stimulation

If your pup is willing, walks are good after deworming.

They are also a good sign of getting better.

Walking can make the metabolism faster.

This means that the worms will get pooped out quicker.

If they don’t want to walk, that’s okay.

Give them a full body rub and play with them at home.

You can also try playing by moving their legs manually.

The exercises all benefit the extraction of the worms. [9]

Weighing Risks and Benefits of Deworming

  • Benefits of Deworming
  • Potential Risks and Comparison
  • Individualized Veterinary Advice

Benefits of Deworming

Puppies and kittens can be born with parasites passed on from their mom.

Dewormers have an adverse effect on the worms.

The worms may or may not show in the stool.

In both cases, deworming should be done in the first 2-4 weeks of life. [10]

By deworming, you can protect yourself too.

Some parasites, like roundworms, can be zoonotic.

This means that they can pass on to humans.

Pregnant women, children, and immuno-deficient people are at a higher risk. [11]

Potential Risks and Comparison

The benefits of deworming outweigh the risks.

Severe reactions to the antiparasitic are very rare.

A big risk is for the vet to administer the drug without knowing the pup’s weight.

This can lead to an underdose or an overdose.

The parasites, if left untreated, can infest your dog’s body.

This can also cause other diseases and a fall in the immune system.

Not deworming leads to more complications than deworming ever could. [12]

Not deworming could be a threat to the owner as well.

Some parasites are zoonotic. [13]

Individualized Veterinary Advice

Vets always encourage deworming because of the benefits.

Through deworming, you will save your dog from a big discomfort.

Every patient needs to be weighed before applying the dewormer.

You should also keep in mind that every parasite needs a separate preventative drug.

Deworming should be done monthly.

Dogs are always in contact with other dogs and nature.

Contracting a parasite can be easy for them. 

After giving a pill, always make sure the dog swallows it.

After a day, the worms die, and they can be seen in their feces. [14]

Differentiating Allergic Reactions From Common Side Effects

  • Recognizing Signs of Allergic Reactions
  • Immediate Veterinary Attention for Severe Reactions
  • Mild Allergic Reactions vs. Anaphylaxis

Recognizing Signs of Allergic Reactions

Allergies for worming tablets are very rare.

It can happen regardless of the way they’re applied.

If it happens, there are a few signs to keep an eye on.

They will have all the normal side effects.

New ones can appear on the skin.

Itchy hives and swelling can lead to scratching.

Swelling in and around the mouth can happen with an oral pill.

The worst symptoms are seizures and anaphylaxis. [15]

Immediate Veterinary Attention for Severe Reactions

A serious reaction like shock or a seizure requires a vet visit.

Anaphylaxis is classified as an urgent case.

This condition can lead to death if not treated.

Mild Allergic Reactions vs. Anaphylaxis

It’s important to know the differences between these two terms.

Mild allergic reactions appear in the span of 2 days.

Anaphylaxis happens within minutes of contact with the antigen. [16]

The symptoms of both are the same.

But their manifestation and severity are very different.

What Are the Side Effects of Deworming a Puppy?

The side effects of deworming a puppy are vomiting, diarrhea, dizziness, and drooling.

A less common side effect is an allergy to the dewormer.

Neurological signs are even rarer.

If any symptoms that are on the common side persist, take your pet to an animal clinic.

Take your pet to the vet immediately if they exhibit an unusual symptom.

Otherwise, your vet should do puppy worming on a monthly basis.

Should You Deworm Your Dog?

Yes, you should deworm your dog regularly.

Parasite prevention is not completely possible.

Dogs are too exposed to the outside world for that.

Keeping up with a deworming schedule is the safest way to keep your dog from suffering.

Parasites can cause severe symptoms and damage inside and outside the body.

There are many drugs your vet can prescribe for different parasites.

Just make sure they’re appropriate for the dog’s weight.