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Last Updated October 8, 2019
Unfortunately, dogs frequently contract worms and other parasites from the environment. And while these creepy crawlies can cause problems for your canine, most are easy to treat — you just need to use a quality dog wormer to clear the infestation.
We’ll help you do exactly that below by recommending the best dog dewormer for large dogs with 7 top picks. Just be sure to review the information carefully and try to select the best worm medicine for your dog’s specific needs.
Note that many authorities recommend using one of these dewormers for dogs every 6 months or so as a preventative measure — even if your dog does not display any symptoms of parasite infestation.
Just be sure to keep your vet in the loop and follow the instructions provided.
8 In 1 Safe Guard Canine Dewormer
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Merck Animal Health Panacur C Canine DeWormer
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Durvet Triple Medium And Large Dog Wormer
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Bayer Quad Dewormer
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Make sure that you review the dewormer information provided carefully to ensure that you select a product that treats the types of parasites your dog has. It’s also important to select an option intended for your dog’s age.
You should also make sure you keep a dog worming treatment in your home, so you can relieve the discomfort and potentially prevent the situation from getting worse. Symptoms to look for include poor appetite, breathing difficulties, sickness, diarrhea, weight loss, and unusual tiredness.
Like most infections, unfortunately, there is not just one solution. There are different kinds of dog worms including tapeworms (which are usually carried by fleas), roundworms (which can also infect people, especially young children), as well as lungworms, which are carried by slugs and snails.
Some treatments for worms will clearly state they are for all forms of worms, whereas others may only treat a specific type of infection.
You will also need to read the label to ensure what age and size of dog the deworming treatment is suitable for, as some may only be for smaller dogs or puppies, and others for larger breeds.
Some dewormers may also be intended to be used on a regular basis to be effective, whereas others may be intended for when an infection has already taken hold.
Different worming medicines use altering forms of delivery such as deworming tablets for dogs that can be hidden in food or regular tablets that can be crushed into food instead.
You may also find deworming treatments in the form of powder sachets that need to be sprinkled over each meal.
Be aware that with these types of treatments, it’s important your dog is not put off by any taste or texture difference so that they actually eat all of the product to receive the medicinal benefits.
While powder forms might seem convenient and work out cheaper in the long run, you should also be aware that unless your dog eats all of the food in its entirety, then it might not get the whole, correct dosage.
You should also research beforehand if the dewormer is likely to give your dog any side effects, especially vomiting and further digestive issues.
Some deworming treatments can contain formulas that could make your dog increasingly unwell, so the best advice is to consult your vet if you are concerned by their original symptoms or how they have reacted to the treatment you have tried so far.
The following are a few of the more important features summarized to help you choose the best dewormer for your dog.
Active Ingredients. Many ingredients are used in combination or alone, and it is important to know that not all of these formulas will work for every type of worm your dog may have. If it is a tapeworm as the result of fleas, for example, then the ingredient fenbendazole won’t eliminate the worms.
Targeted Parasites. Don’t waste your time or money giving your dog the wrong dewormer. With two types of tapeworms, you will soon find that not all over the counter dewormers will eliminate both. When choosing the dewormer, make sure to see which parasites it is meant to target.
Doses. You can find dewormers that come in either one or three-day dosage options. However, some natural dewormers are safe enough to use on a daily basis.
Administering Treatment. Chewable tablets and liquid treatments may be the best way to administer the treatment to your dog or puppy. Tablets can be crushed up, and this is one of the most popular methods of administration chosen by pet owners.
Side Effects. Never use a brand that is not well-known or reliable. You want a reputable brand that is safe for your dog or puppy, so it isn’t hard on their digestive system or cause them any other amount of pain or discomfort.
Age and Weight. These products are all labeled by size and age, so choose the one most appropriate for your canine companion. There are some puppy options that can be given to a puppy from 2-weeks old as well as very small dogs, while others are made specifically for larger and older dogs. To ensure that the dewormer does its job, you want to make sure that the dose you use is correct.
One of the biggest questions often asked by a pet owner is if over the counter dewormers are safe to administer to their puppy. When you choose a dewormer for a puppy, you should get one that is formulated to specifically target the worms that a mother commonly passes to her puppies.
During nursing, puppies can get the infection again. They can also get it from eating things off of the ground. So, you will most likely have to treat a puppy several times, so you want to have a dewormer that is easy to administer and gentle so as not to upset their sensitive stomach.
This over-the-counter dewormer is a powder which you sprinkle over your dog’s food 3 times daily. On the one hand, this makes it easy to deliver to the dog. However, it depends on how your dog reacts to it.
As it’s a powder and covers all the food, if your dog first tastes the powder and decides it doesn’t like it, then it could reject the whole food, meaning they will not get the benefits and you’ll have to try another product.
Not exactly ideal in the middle of an infection, so you might want to try this out during the 6-month deworming process that this product recommends.
If your dog doesn’t reject the powder mixed in with their food, then it actually does deliver protection and treatment against a multitude of different worms including tapeworms, roundworms, hookworms, and whipworms.
The dosage depends on the size of your dog, and there is a size guide on the back to instruct you, so you give your dog the right amount.
The box is also available in 3 different sizes, which is ideal if you own more than one dog or if you are in the middle of an infection.
The 8 in 1 canine dewormer is also a very good value compared to other brands which are upwards of 6 times the cost for their deworming treatments. On the other hand, some owners have reported back that due to the low cost, it is not effective and did not cure their dog.
Despite it being a best-selling product, it may not be the best large dog dewormer out there, which is why it’s always advisable to try this as part of your regular dog health and grooming routine to see how your dog gets on with it, rather than jumping in at the time of infection.
Although the 8 In 1 Safe-Guard Canine Dewormer For Large Dogs is a popular large dog dewormer that can be administered 3 times daily, it has mixed reviews when it comes to how the dog reacts to the taste of their food, and also how effective it is at actually treating worms. The company also suggests adding water to aid in the mixing, especially if you use dry dog food.
Some dogs reacted very well to this product, and it quickly cleared up all their worm issues, whereas other owners reported side effects and a general lack of improvement so moved on to other treatments.
It is much more affordable than other worm treatments so it shouldn’t be ruled out altogether, although it should probably be tested out first during your dog’s recommended 6-month deworming process, as from those who have tried this so far, the results seem pretty inconclusive.
Panacur C is another brand that offers relief from hookworms, roundworms, tapeworms, and whipworms, which are some of the most common types your dog is likely to suffer from as well as giardia which is a nasty intestinal infection.
Like other brands of this nature, it also follows a powder form to be administered over your dog’s food. The powder contains a key ingredient called fenbendazole, which kills parasites by binding to a parasitic protein, which damages the cell structure of the parasite, causing it to die off.
Therefore, if used correctly at the right dosage, it will rid your dog of any of the parasites listed on the box.
Each packet treats 40 lbs. and needs to be given once a day for 3 consecutive days. There are also other packets available if your dog’s size falls outside of this category, though keep in mind this particular size is one use per dog, and not for multiple treatments (such as once every six months as recommended) or if you own more than one dog.
You may require more than one packet a time which will ramp up the costs in the long run.
Overall the Panacur C has a good reputation among owners and is also commonly recommended by vets. Only a small percentage (1%) of dogs tested had adverse reactions such as vomiting or stomach upset.
However, the majority of owners across a large variety of breeds reported this dewormer was quick to bring everything under control, and most reported a very satisfactory experience, especially in terms of getting their dog back to normal and out of discomfort. It is definitely one of the best dog dewormers on the market.
Panacur C Canine Dewormer has your dog covered when it comes to deworming, and best of all, this product is reasonably priced too. Perhaps one of the best features with this dewormer is the addition of fenbendazole, which kills a number of parasites that your dog is most likely to be infected by.
Though similar to other powdered forms of deworming treatments, you will need to ensure your dog eats all of the food it is sprinkled over for it to be effective, which can be much more troublesome compared to tablet or capsule form where the full dose is administered in one go.
The 12 tablet Durvet Broad Spectrum De-Wormer doesn’t kid around when it comes to deworming; in fact, it’s capable of treating the following infections: roundworms (Toxocara Canis, Toxascaris leonina), hookworms (Ancylostoma caninum, Ancylostoma braziliense, Uncinaria stenocephala) and tapeworms (Dipylidium caninum, Taenia pisiformis) in dogs as well as puppies.
If you buy the smaller tablet pack at two doses, be aware that one dose is actually both pills taken in stages; therefore, if you own multiple dogs or require tablets for a longer length of time (given you will need to deworm each dog you own every 6 months), then you may have to buy the larger 12-dose pack.
As this product is only available in 2 or 12 doses, it may work out considerably more expensive, especially if you own more than one dog.
Remember, each dog will need to be dosed at a separate time also (around two weeks apart).
The first dose of this product will only kill the adult parasites, which is why the second dose is equally as important as this will kill the more immature parasites.
If you don’t follow up with the second dose, you may have to repeat the whole process again, which could be a costly affair not to mention putting your dog’s health at risk.
While this treatment is only recommended for medium and larger dogs, Durvet states they make a different treatment that is suitable for puppies. While this may seem like an inconvenience, it’s important to administer the right dosage to each size dog you own.
Overall, as a broad spectrum deworming treatment, if followed correctly, these are the best dog worming tablets at killing a wide range of parasites that could make your dog very sick if left untreated. It also has not had the same reports of making the dog unwell with digestive issues as other deworming treatments have.
While the Durvet Broad-Spectrum Dewormer could work out to be a costly affair, especially if you own more than one dog, it’s an easy way to administer the treatment to your dog. Instead of sprinkling a powder over their food, you simply give them 1 tablet, which also ensures all of the dosage is received.
It’s a powerful deworming treatment against 7 different types of worms, all of which could cause serious harm and distress to your dog. It does this without the nasty side effects seen in some powdered treatment versions, and overall, it has a very high positive feedback rating from owners.
The dog worming tablets are good for 2 years from purchase, which is reassuring if you are buying in bulk with the intention to treat every 6 months as is recommended, or if you have more than one dog to treat.
Bayer Quad Dewormer is a chewable dog deworming tablet designed to eliminate four different types of parasites that commonly afflict dogs, including tapeworms, roundworms, whipworms, and hookworms.
Chewable tablets are often the most convenient way to administer a worming medication to your dog, and they make it easy to correctly administer the correct dosage.
Unlike powders which your dog may pick around, you can simply watch your dog eat the tablet to verify he obtained the proper dosage. However, not all dogs find chewable tablets palatable. Fortunately, Bayer Quad Dewormer has a flavor that most dogs like.
This medication is available for dogs of all sizes (small, medium and large). The broad-spectrum worming tablets designed for large dogs are appropriate for all individuals weighing more than 45 pounds. Each pack comes with four tablets so that you can treat the problem several times to help completely eradicate the worms.
One of the most effective over-the-counter dog dewormers available for treating worms, Bayer Quad Dewormer is an excellent choice for many owners. Several owners reported that they began seeing tapeworm fragments or dead roundworms in their dog’s stool within 24 hours of administering the medicine.
It’s also an affordable product, made by a very well-known manufacturer, which will help you purchase with confidence.
Nemex-2 is a liquid worming medication that is specifically designed to target roundworms and hookworms – two of the most common parasites that afflict dogs. This makes it a good choice for the routine worming of puppies and adult dogs.
Liquid worming medications are often relatively easy to administer, and it is pretty easy to ensure that you are giving your dog the correct dosage, as relatively little of the medication is necessary.
In fact, it takes only one teaspoon of this medication for every 10 pounds of your dog’s body weight. Additionally, most dogs appear to like the taste of Nemex 2 and take it willingly.
You can purchase this medication in either a 2-ounce bottle or a 16-ounce bottle if you need to treat multiple dogs. It is safe for puppies, as long as they are at least 2 weeks old.
Nemex 2 is a great choice for owners of dogs suffering from roundworm or hookworm infestations. The liquid form is easy to administer, and most dogs appear to find it tasty.
It is available in two different sizes, it is reasonably priced, and most owners reported that it was very effective for ridding their dog of worms.
The following are a couple of the honorable mentions we thought we would include on this list to give you a better idea of your available over the counter dewormer options.
This is a safe and non-chemical alternative to the other canine dewormers included on our list. It comes from freshwater deposits and is made with raw, natural whole food ingredients.
The Diatomaceous Earth contains the dried skeletons of microscopic sea creatures that are known as diatoms. It is safe and gentle enough to be used as a daily supplement.
These are chewable deworming tablets for dogs and helps control seven different worm species including two types of tapeworms, two types of roundworms, and three types of hookworms.
They are safe to give dogs and puppies over 12 weeks of age and it is also a suitable dewormer for small dogs – those weighing between 6 and 25 pounds. It is an easy and convenient worming treatment for your dog.
Worms and protozoans can wreak havoc on your dog’s intestinal tract, and they’ll often trigger a number of troubling symptoms.
Different worms affect dogs in different ways. In fact, individual dogs will often suffer from different reactions to the same parasite.
Some of the most commonly observed symptoms of worms in dogs include:
But perhaps the most obvious sign of a worm infestation is the appearance of worms or eggs in your dog’s stool (they may also be visible if your dog vomits). Sometimes the worms expelled may be dead, but they are often alive.
Seeing a wiggling mass of worms emerge from your dog’s body can be upsetting, but it is not particularly problematic, so don’t panic.
Different worms and parasites infect dogs in different ways. We’ll discuss the specific route by which different types of worms infect dogs below, but there are three basic methods of transmission:
The majority of worms and other parasites that infect dogs are transmitted via the fecal-oral route. This occurs when a dog inadvertently ingests eggs or larvae that’s been passed in the feces of other animals. Dogs can also re-infect themselves in this manner, which can lead to very significant infestations.
Heartworms are spread through the bites of infected mosquitoes. And while not every mosquito is infected with heartworms, all it takes is a single bite from an infected individual to cause your dog to suffer from heartworm disease.
Most dogs who contract tapeworms catch them when they accidentally consume fleas. Dogs can also contract tapeworms by eating contaminated meat, but this isn’t very common in the modern world.
There are a number of different worms that can infect dogs, and although they all cause broadly similar symptoms, there are a number of differences between the various species. Some rarely cause serious health problems, while others may imperil your dog’s very life if left untreated.
Some respond well to a variety of common over-the-counter medications, while others only respond to very specific treatments.
The primary types of worms that affect dogs include:
Roundworms are some of the most common parasites that afflict dogs, and they’re particularly common in puppies. In fact, the vast majority of puppies have roundworm infestations at birth – and those who aren’t born with them usually contract them in short order by drinking their mother’s milk.
Roundworms often migrate quite a bit inside a dog’s body, and they are frequently seen in a dog’s stool or vomit. Roundworm infestations can quickly reach plague-like proportions, as each female roundworm can produce more than 200,000 eggs each day. And unfortunately, these eggs can persist in the environment (in a dormant state) for years.
Because roundworms are large by parasite standards, and they are quite prolific, they can actually fill a pet’s intestinal tract. This can cause canines to develop a pot-bellied appearance, and, if left untreated, eventually result in an intestinal blockage.
Heartworms are roundworms that can cause a very serious illness called heartworm disease.
Heartworms are unlike many of the other worms that commonly afflict dogs, as they’re spread via mosquitos. The heartworm larvae enter your dog’s bloodstream during the mosquito’s feeding activity, before spending the next five to seven months maturing. At this point, they migrate to your dog’s heart and begin reproducing.
Heartworms can grow to about a foot in length, and your dog may end up with more than 100 of them living inside his heart. This can reduce the pumping efficiency of your dog’s heart, and lead to congestive heart failure. Left untreated, heartworm disease is often fatal.
There are treatments available for heartworm disease, and they’re often effective. However, treatment is very expensive, and you’ll need to limit your dog’s activity for several months while the medications are killing the worms. If you don’t, small pieces of the dying worms may break off and cause deadly blockages of the pulmonary artery.
Fortunately, heartworm disease is very easy to prevent with a simple oral tablet, given about once per month. You’ll need to obtain the medication from your vet, but it is generally pretty affordable.
Whipworms rarely cause the types of serious problems that roundworms do, but they can be very unpleasant for dogs. Unfortunately, whipworms do not pass very many eggs, so they can be tough to positively identify when analyzing stool samples.
Because they are also difficult to diagnose via fecal analysis, veterinarians often elect to treat dogs at risk for whipworms (including young puppies, dogs housed in kennels and dogs living in homes with other dogs who’ve been diagnosed as having whipworms), whether they show symptoms of an infestation or not.
Whipworms are very small, although they are occasionally noted in a dog’s stool. They typically look like a long hair, although one end appears larger than the other. The two most common symptoms associated with whipworm infestations include weight loss and mucus-covered stools.
Hookworms derive their name from their sharp mouth parts, which enable them to cling to the wall of the small intestines. Once attached, they begin feeding on their host’s blood. This can be very dangerous for dogs – particularly young puppies – as it can lead to anemia.
Adult dogs can become sick from hookworms, but puppies occasionally die from severe infestations.
And hookworms aren’t only dangerous; they’re also easy for your dog to contract. Hookworm larvae may be ingested from the environment (this is how most adult dogs contract them), but puppies typically acquire them while in their mother’s uterus or while breastfeeding shortly after birth.
Bloody stools, anemia, weight loss, and lethargy are some of the most common symptoms of hookworm infestations. Fortunately, hookworms are relatively easy to diagnose by conducting a fecal analysis.
Tapeworms have an indirect lifecycle, which means that they require more than one type of host to complete their lifecycle. There are a variety of different tapeworm species, but those that most frequently afflict dogs utilize fleas as the intermediate host. Their larvae live inside the bodies of fleas, and when a dog inadvertently eats a flea while grooming himself, the tapeworm can be transmitted to his body.
Tapeworms grow pretty large – many reach or exceed 6 inches in length. However, they’re perpetually shedding the terminal segments of their body (this is how they reproduce), so their length fluctuates periodically. Unlike many other types of worms, which are likely to occur in high numbers, most tapeworm infestations will consist of very few individual worms.
Tapeworms are usually diagnosed by finding body segments (which look like grains of rice) in your dog’s feces. Tapeworms are often very difficult to eradicate with over-the-counter medications, and you may need your vet’s help to completely treat the problem.
Not all parasites that affect dogs are worms. Protozoans are single-celled organisms that can also infest your dog’s body and make him sick. There are a variety of different protozoans that can afflict dogs, but Coccidia and Giardia are two of the most common. Dogs can also contract cryptosporidium, which is a protozoan that can also sicken you and your family.
Most protozoans cause broadly similar symptoms, including bloody diarrhea, weight loss, inappetence and a general failure to thrive. Protozoans can be very difficult to positively diagnose, as they are very small and only produce eggs periodically. Accordingly, multiple fecal examinations are often needed.
Few over-the-counter medications will treat protozoan infestations, so it is usually necessary to solicit your vet’s help in treating the problem.
There are a lot of different worms that infect dogs, and it can be difficult for some owners to remember which worms cause which symptoms, and which ones are likely to cause the most significant problems. We’ve made the following chart to try to help with this problem.
|Parasite||Primary Symptoms||Visible in Stools, Vomit or Sputum?||Potentially Fatal?||A Threat to Humans?|
|Heartworms||None initially. Eventually, most dogs will become lethargic and tire easily.||No.||Yes. Heartworms are very dangerous for dogs.||No.|
|Tapeworms||Typically, tapeworms don’t cause symptoms, although dogs may eventually begin losing weight.||Small, rice-like segments are often visible.||Unlikely||No.|
|Roundworms||Pot-bellied appearance, diarrhea, weight loss, loss of appetite.||Spaghetti-like worms often expelled in feces, vomit or sputum.||Possible, but unlikely.||Unlikely.|
|Hookworms||Diarrhea, constipation, lack of appetite and coughing||No.||Yes. Hookworm infestations can be deadly.||Yes.|
|Whipworms||Weight loss and mucous-covered stools.||Rarely. They appear like small hairs that are large at one end.||Possible, but unlikely.||No.|
|Protozoans||Diarrhea, which may occasionally be bloody or extremely frequent.||No.||Yes. Protozoans can cause death if left untreated.||Yes.|
Most dog worms can be treated with simple and safe medications. Some of these deworming medications are available over-the-counter, but others will require a prescription from your vet. Most of the common medications used to treat worms are effective on more than one species, which helps to simplify the treatment in many cases.
It is also important to keep your dog’s environment exceptionally clean during and after the treatment process. Many of the most common internal parasites and worms that infect dogs are spread via the fecal-oral route. This means that the eggs or larvae are expelled in a dog’s feces, and they infect other dogs when they’re inadvertently ingested.
So, it is important to keep your dog, his bed, and your backyard clean while battling a worm infestation.
Ideally, you should always have fecal samples examined by your veterinarian so that you can determine the exact parasites that are infecting your pet. This will allow you to use a medication that specifically targets the worms or protozoans, causing your dog problems.
This type of “targeted” approach is typically preferred by veterinarians, as it allows you to treat parasite problems with precision. It also eliminates the need to administer any unnecessary medications to your dog. This is important, as dogs occasionally suffer unpleasant side effects after taking worming medications.
It is also the best way to treat dogs with ongoing problems, which haven’t responded to prior attempts. Like most other worm treatments, you’ll usually need to administer several rounds of medication to completely eliminate the problem.
If you don’t have the time or budget for multiple visits to the vet’s office, you may want to consider trying a home testing kit, such as the Perfect Pet Products Fecal Worm Test.
To use this test, you’ll simply need to obtain a sample of your dog’s feces, enclose it in the included sample bag, and mail it to the Perfect Pet Products lab.
Within 24 hours, they’ll notify you of the specific parasites that are afflicting your pet.
In contrast to the “targeted” approach described above, the “shotgun” approach seeks to eliminate most of the common parasites that afflict dogs, without spending a lot of time trying to identify the specific worms or protozoans present.
So, instead of analyzing fecal samples and then using medications specifically designed to eliminate specific parasites, the “shotgun” method typically utilizes a broad-spectrum deworming medication that is designed to treat a variety of different parasites. This approach is often used preemptively, even when parasite problems aren’t suspected.
The benefit of this approach is that it will help owners save a little time and money, and it will usually eliminate the bulk of the parasites present. But the downside is that it may not eradicate all of the parasites in your dog’s body, including those that may cause troubling symptoms.
Given these benefits and drawbacks, this approach is often best suited for routine de-worming and whenever it is necessary to treat a large number of dogs at one time.
The following are some of the most commonly asked questions regarding over the counter dewormers for your dog or puppy.
Worms in dogs and other parasites are certainly concerning, but they needn’t cause you to panic. Just select one of the best dewormers for dogs above, administer it in the manner indicated on the package, and keep your vet in the loop.
The dewormers will go straight to the dog’s digestive system, and this is where the parasites have set up shop. So, the medicine can begin working as soon as 24 hours after it has been administered to up to one week. It is important to note that the time it takes is largely dependent on the type of dewormer you chose, the number of treatments used, and how big the infestation was.
When you begin to notice the symptoms, and you receive a proper diagnosis from your veterinarian, you can begin to treat your dog. Several treatments spread out over a few weeks’ time may be necessary for larger infestations.
However, most veterinarians recommend treatment for a dog every six months. For a puppy, treatment can start as early as 2-weeks and should be continued every two weeks until the puppy reaches three months old.
Yes. Older people, children, and those with compromised immune systems may be affected by a dog that is infested with worms. When an infected dog comes into contact with these people, the dogs should be given treatments regularly.
Worms in dogs and other parasites are certainly concerning, but they needn’t cause you to panic. Just select one of the best dewormers for dogs above, administer it in the manner indicated on the package, and keep your vet in the loop.
In no time at all, your dog will expel the parasites and begin feeling great again.