Accidentally Gave My Dog 2 Doses of Heartgard – Should You Be Worried?

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You might wonder how is it possible accidentally to give your dog 2 doses of Heartgard?

There could have been multiple reasons for this mishap. One of the likely causes is that you might have misread the instructions on the package and given your dog two doses instead of one without first consulting your dog’s veterinarian. Yet another possibility is that the medication got mixed up, and in confusion, you accidentally ended up repeating the dose, making it two instead of one.

It is very easy to make a mistake like this, so be sure to take your time and double-check the dosage before you give it to your pet.

To err is to human,” and we all make mistakes every now and then. It doesn’t mean we love our pets any lesser. Honestly, the composition of Heartgard is such that it won’t even make much of a difference in case you have doubled the dose. However, it is neither recommended nor encouraged to give more than the prescribed dosage of any medicine. Hence, it is always better to be safe than sorry. If you have mistakenly doubled the dose of Heartgard, it is best to call your vet and seek professional advice.

What is Heartworm?

What is Heartworm

Heartworm disease is an infection caused by a worm parasite that can have fatal consequences. It is known to be transmitted by mosquitoes. Mosquitoes are known to carry the heartworm larvae from one animal to another. If you were offering Heartgard medications to your dog, you are probably aware of the disease and its consequences.

So, now you know about the disease, let us know more about how this disease can i mpact your pet’s health, and how Heartgard is the right medicine prescribed by your dog’s vet to ensure a speedy recovery.

What Symptoms to Look Out For Heartgard Overdose in Dogs?

Overdose of Heartgard may have serious health repercussions on your dog. The symptoms can be mild and non-alarming. And if your pet dog is suffering from vomiting and diarrhea, there can be other symptoms that may follow. Some of them are:

1. Loss of Appetite

Vomiting can make your dog weak, and in the long run, your canine friend may suffer from loss of appetite. They may refuse their favorite treat and sleep throughout the day. So, please look out if your dog is avoiding meals.

2. Lethargy

Lack of proper nutrition may make your furry friends weaker, and they may become lethargic. They may not like to move from their resting position, keep yawning, and sleep throughout the day. So, an unusual lazy dog implies that she/he has been administered with an overdose of Heartgard.

3. Excessive Drooling

Drooling is one of the most common features among dogs, even in general. But if your dog is drooling too much, especially after being administered Heartgard, please be cautious. This may indicate that the amount of Heartgard it has consumed is more than the prescribed quantity.

4. Seizures

One of the most severe symptoms of an overdose of Heartgard is violent fits or frequent episodes of seizures. This is a symptom that is easy to observe since most dogs do not suffer from seizures under normal circumstances. So, if you find your pet having seizures after consuming Heartgard, immediately contact your veterinarian.

5. Skin Irritation

Skin irritation is another symptom of an overdose of Heartgard, and if you find your dog to be frequently using its paws to scratch itself all over, you probably have fed your pet buddy more Heartgard than you should have.

6. Blood in the Stool

This symptom is a serious one and is easy to detect. The moment you find blood in your dog’s stool, especially after being administered with Heartgard, immediately take your pet to the doctor and follow up on the required procedure.

7. Change in Behavior

Overdose of Heartgard may lead to erratic and irrational behavior in your dog. They may act weird and become aggressive. So, any erratic behavior like unnecessary biting is an indication your dog is suffering from an overdose of Heartgard.

Benefits of Using Heartgard

Benefits of Using Heartgard

Now that you have known the repercussions caused due to an overdose of Heartgard, that should not be a reason to dissuade you from administering your dog with Heartgard.

Prevention of Heartworm Disease

Heartgard works by killing heartworm larvae that are present in the dog’s bloodstream.

Reduced Risk of Other Diseases Caused by Heartworm Infection

Heartworm infection can cause a variety of problems in pets, ranging from respiratory to neurological. Early diagnosis and treatment are essential for the best possible outcome for your pet.

Easy to Administer

Most veterinarians administer Heartgard to dogs at an early stage to ensure that the infection subsides as soon as possible.

Convenient Once-a-month Chewable Tablet

Heartgard should be given to dogs once a month, and it is best to provide it at a particular date in a month. As the tablets are chewable, people mistakenly give two doses to their dog.

How Much is Too Much Heartgard For Dogs?

Heartgard contains ivermectin and pyrantel. The minimum dosage of this salt combines 2.72 mcg/lb and 2.27mg/lb. Since this combination is strong, administering Heartgard is not favored if your puppy is less than six weeks old. Therefore, it should be administered according to the weight of your dog. Also, if you have a big dog weighing over 100 lb, there are chewable tablets of Heartgard in the market.

Ideally, if your dog weighs up to 25 lb, a 68 mcg of Ivermectin content and 57 mg of Pyrantel content should suffice. If your dog weighs anywhere between 26 lb to 50 lv, 136 mcg of Ivermectin content and 114 mg of Pyrantel content is required. For dogs weighing anywhere between 51 lb to 100 lb: the prescribed dosage of Ivermectin and Pyrantel content is 272 mcg and 227 mg, respectively.

What Should I Do If I Can’t Remember If I Gave My Dog Heartworm Medicine?

First of all, relax! A medicine like Heartgard is meant to help your pet fight a deadly disease, and the way it works is by killing the worms attacking your pet. The treatment will take time to work, and if you can’t recall if you gave your dog the medicine, you can administer another dose just to be sure.

You can use a few tricks to ensure that you remember to give your pet the medicine next time.


Mark your calendar based on the prescription. You can also set reminders on your phone to ensure that you do not miss the day or time when the medication is due.

Mix in Food

If your dog is acting up about taking medicine and is reluctant to follow instructions, you can mix the medicinal drugs in their food to ensure there is no trace of medicine.

Pill Case

Another efficient way is to maintain a pill case. The probability of forgetting to give your dog the required Heartgard dose is significantly reduced when you have a pill case. This is because you will have to open the case and take out the pill every time you need to give it to your dog.


Q1. Can I Give My Dog A Higher Dose Of Heartgard?

Ans: Any medicine, not just Heartgard, should be given in moderation. It is advisable to increase the pace gradually and keep an eye on your dog’s comfort level. In case your dog shows no apparent symptoms with the dosage, there is no need to worry.
Before giving your dog a higher dose of Heartgard, it is highly recommended to check with your dog’s vet first. However, if your dog’s vet has already recommended a dose for your dog and given you the green light, then you can go ahead with caution. Ensure that you increase the dosage gradually.

Q2. What are the active ingredients in Heartgard?

Ans: The active ingredients in Heartgard are ivermectin and pyrantel pamoate.

Q3. What are the dosages for Heartgard?

Ans: The dosages for Heartgard vary depending on the weight of the dog. The recommended dosage is 0.5 mg/kg of body weight, given as a single dose each month.

Final Verdict

We all want to do our best to ensure the well-being of our pets. There can be a few errors in our judgment every now and then. Honestly, Heartgard has more benefits than drawbacks. You can always check with your vet in case something goes wrong. Quick treatment can prevent health issues. Yet prevention is always better than cure.

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