Credelio and Credelio Quattro for Dogs

PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Are Credelio and Credelio Quattro Used for in Dogs?

Generally speaking, both Credelio and Credelio Quattro are monthly prescription antiparasitic medications for dogs.

With four active ingredients lotilaner, moxidectin, praziquantel, and pyrantel, Credelio Quattro for dogs provides the broadest* parasite protection of its kind covering six types of parasites: fleas, ticks and four types of worms (heartworms, roundworms, hookworms, and tapeworms) in one chewable tablet.

Credelio Quattro is available for puppies and dogs 8 weeks of age and older who weigh at least 3.3 pounds or greater. The beef flavored tablet is available in five different doses; your veterinarian will determine the appropriate dose based on your pet’s weight.

With its active ingredient lotilaner, Credelio for dogs is a monthly chewable tablet that treats and prevents flea and tick infestations in dogs and puppies.

Credelio is available for puppies and dogs 8 weeks of age and older who weigh at least 4.4 pounds or greater. The beef-flavored tablet is available in five different doses; your veterinarian will determine the appropriate dose based on your pet’s weight.

Both Credelio and Credelio Quattro are only available by prescription from your veterinarian.

Though beef flavored, both Credelio and Credelio Quattro tablets are beef allergen-free, containing pork liver and soy but no actual beef.

A recent study showed that three consecutive monthly lotilaner treatments resulted in a 100% reduction in flea infestations among participating dogs. The same study demonstrated that the flavored, chewable Credelio tablets were palatable, easily administered by the pet parents, and that the safety and efficacy of Credelio was maintained regardless of geography, season, and breed of treated dog.

An additional U.S. field study involving 191 dogs demonstrated that almost nine out of 10 dogs accepted Credelio Quattro.

Are Credelio and Credelio Quattro FDA-Approved? 

Yes, Credelio Quattro for dogs is an FDA-approved antiparasitic product with four ingredients, given monthly, for the prevention of heartworm disease and for the treatment and control of roundworms, hookworms, and tapeworms.

Credelio Quattro is also FDA-approved for monthly treatment and prevention of flea and tick infestations in dogs and puppies.

Credelio for dogs is FDA-approved for monthly treatment and prevention of flea and tick infestations in dogs and puppies.

Speak with your veterinarian about whether Credelio or Credelio Quattro is right for your dog. 

Credelio and Credelio Quattro Considerations for Dogs

Credelio and Credelio Quattro should be used with caution in dogs with a history of seizures or neurological disorders. Lotilaner, one of the ingredients in both Credelio and Credelio Quattro, is a member of the isoxazoline class, which has been associated with neurologic adverse reactions (see Side Effects section below for more information).

Dogs should be tested for heartworms before starting Credelio Quattro, as this medication is not effective against adult heartworms.

It is important to note that the safe use of Credelio and Credelio Quattro had not been evaluated in breeding, pregnant, or lactating dogs at the time of this publication.

How Credelio and Credelio Quattro Work in Dogs

Lotilaner, the active ingredient in Credelio and one of the four active ingredients in Credelio Quattro, belongs to a newer class of flea and tick preventives called isoxazolines. Lotilaner eliminates fleas and ticks by overwhelming these parasites’ nervous system, causing paralysis and death.

Studies conducted indicated that Credelio starts killing fleas and ticks in just a few hours and significantly reduced the amount of fleas by 100% in 12 hours, staying effective for 30 days.

In an additional study, Credelio (lotilaner) was found more efficacious than afoxolaner (NexGard) and the combination of sarolaner-moxidectin-pyrantel (Simparica Trio) in quickly controlling a Lone Star tick infestation. The results showed that lotilaner had a more rapid onset of lethal activity and sustained its speed advantage throughout the month-long treatment period. In contrast, the speed of kill of the afoxolaner and combination sarolaner products declined between day 0 and 28.

Credelio and Credelio Quattro contain extra-purified lotilaner, with the inactive part of the compound removed to decrease the potential for additional side effects.

Credelio Quattro contains the same established dose of lotilaner found in Credelio plus three other active ingredients: moxidectin (for protection against heartworms, hookworms, and roundworms), praziquantel (for protection against two species of tapeworms), and pyrantel (for protection against hookworms and roundworms).

Some intestinal parasites—hookworms, roundworms, and a certain species of tapeworm—not only threaten dogs but also pose a health risk to people. Credelio Quattro protects your dog and your household from parasitic infections.

How To Give Credelio and Credelio Quattro to Dogs

Follow the directions on the drug label or as provided by your veterinarian.

• Credelio and Credelio Quattro are given by mouth once a month with a meal or within 30 minutes after feeding.

• Give Credelio or Credelio Quattro once a month year-round for the best protection against parasites.

• Make sure your dog consumes the complete dose, and that part of the tablet is not lost or refused.

• If your dog vomits within one hour after administration of Credelio Quattro, give your dog a new dose.

• Dosing is based on body weight. Your veterinarian can let you know the appropriate dose for your dog.

• Do not use cat medications on dogs or dog medications on cats. This can cause serious problems, including a lack of effectiveness or an overdose.

Missed a Dose? 

Speak with your veterinarian about what to do if you forget to give a dose of Credelio or Credelio Quattro. 

Generally, your vet may instruct you to give it immediately when you remember and resume a monthly dosing schedule for your dog.

Do not give extra or double doses. 

Possible Side Effects of Credelio and Credelio Quattro for Dogs

Both Credelio and Credelio Quattro are well-tolerated in dogs and have wide margins of safety.

Side effects may include:

• Vomiting

• Diarrhea

• Weight loss

• Decreased appetite or loss of appetite

• Dermatitis

• Itching

• Hair loss

• Increased urination (Credelio only)

• Elevated Blood Urea Nitrogen (BUN) kidney level (Credelio only)

Neurologic side effects have been seen after using medications in this class of drugs (isoxazolines). Tell your veterinarian if your dog has a history of seizures or other neurologic disease. Neurologic side effects may include:

• Muscle tremors

• Loss of balance (incoordination)

• Seizures

Human Side Effects 

Due to possible side effects, humans should never use medicine dispensed for their pets, and pets should not be given any medicine dispensed for a human’s use.

Wash your hands after handling this medication. 

If you accidentally ingest a pet medication, seek medical attention in person or call Poison Control at 800-222-1222. 

Monitoring Your Pet 

Dogs should be tested for existing heartworm infections before administration of Credelio Quattro, as it is not effective against adult heartworms.

No specific monitoring is required for Credelio.

Your veterinarian may recommend routine testing depending on your dog’s individual needs, other medications they may be prescribed, and/or the issue that initially caused your dog to be placed on this medication. 

When To Call Your Vet 

Call your veterinarian if you see any of the following: 

• Severe side effects (above) 

• Your pet’s condition worsens or does not improve with treatment 

• You see or suspect an overdose 

• If you have additional questions or concerns about the use of Credelio or Credelio Quattro

Credelio and Credelio Quattro Overdose Concerns in Dogs

Overdoses of these medications are rare.

In a margin of safety study for Credelio, Beagle puppies who were given three times or five times the maximum labeled dose of Credelio every 28 days for eight consecutive doses showed no clinically relevant, treatment-related effects.

In a margin of safety study for Credelio Quattro, Beagle puppies were given three times or five times the maximum labeled dose at 28-day intervals for nine treatments. Clinical chemistry findings and observations included diarrhea, vomiting, and drooling on the day of dosing, as well an increased liver level (bile acids).

If you suspect an overdose, immediately seek emergency veterinary care or contact an animal poison control center. Consultation fees often apply. 

• Pet Poison Helpline 855-764-7661  

• ASPCA Animal Poison Control 888-426-4435  

How To Store Credelio and Credelio Quattro for Dogs

Keep the following storage tips in mind for this medication: 

• These products should be stored at controlled temperatures between 59–77 degrees Fahrenheit (15–25 degrees Celsius). Brief exposures to temperatures of 41–104 degrees Fahrenheit (5–40 degrees Celsius) are acceptable.

• Keep the medication in the provided blister packs until ready to use to protect from moisture and light.

• Keep out of reach of children and pets.