Fenbendazole for Dogs and Cats (Panacur, Safe-Guard)
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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 Is Fenbendazole Used for in Dogs and Cats?
Fenbendazole is the active ingredient in several common veterinary deworming medications for dogs and cats for the removal of intestinal worms, including roundworms, hookworms, whipworms, tapeworms, and protozoal parasites, like Giardia.
Fenbendazole is available in oral formulations under the brand names Panacur and Safe-Guard.
Fenbendazole is available over the counter as single-use packets or by prescription from your vet in granule, liquid, chew, and capsule forms.
Is Fenbendazole FDA-Approved?
In dogs, fenbendazole is FDA-approved to treat roundworms, hookworms, whipworms, and tapeworms.
It is also FDA-approved for use in veterinary medicine to treat a wide variety of worms in horses, cattle, swine, and goats.
Fenbendazole is currently not FDA-approved as a veterinary medication in other species such as cats and ferrets. However, it is readily utilized in the veterinary field, and veterinarians can legally prescribe certain human drugs for use in animals in certain circumstances. This is called extra-label or off-label use because this use is not described on the drug label.
Speak with your veterinarian about whether fenbendazole is right for your pet.
Compounded Fenbendazole
In certain circumstances, your vet may recommend a compounded formulation of fenbendazole.
Compounded medications are prescribed, for example, if:
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There’s a specific reason your pet’s health can’t be managed by an FDA-approved drug, such as if your pet has trouble taking pills in capsule form
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The dosage strength is not commercially available
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The pet is allergic to an ingredient in the FDA-approved medication
Compounded medications are not FDA-approved. They are formulated by your veterinarian and dispensed either by a licensed pharmacist or veterinarian on an individual basis to best suit a patient’s particular needs.
Fenbendazole Considerations for Dogs and Cats
Fenbendazole should be used with caution in pets who are hypersensitive to the medication.
Giving fenbendazole with certain medications can result in health risks to your pet, so it’s important to discuss your pet’s medications, including vitamins and supplements, and medical conditions with your veterinarian.
Fenbendazole does not treat all types of parasites, including the tapeworm spread by fleas. A different type of deworming medication may be necessary, especially if parasites are still present after treatment. Your veterinarian may perform fecal tests to ensure the medication is working and to determine if parasites are still present.
How Fenbendazole Works in Dogs and Cats
Fenbendazole blocks the ability of worms to produce energy, which ultimately starves and kills the parasite.
Immature life stages, such as larvae or eggs, may also be affected in some types of worms.
How To Give Fenbendazole to Dogs and Cats
Follow the directions on the drug label or as provided by your veterinarian.
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Fenbendazole is best absorbed if given with food.
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Many puppies are dewormed after weaning at 6, 8, 10, and 12 weeks of age. The nursing mother dog should also be dewormed.
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Adult dogs may require deworming twice yearly or when parasites are present.
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Your veterinarian will determine a schedule that is appropriate for your pet.
Missed a Dose?
Speak with your veterinarian about what to do if you forget to give a dose of fenbendazole.
Generally, your vet may instruct you to give it when you remember, or if it is almost time for your pet’s next dose, to skip the missed dose and resume your normal dosing schedule.
Do not give extra or double doses.
Possible Side Effects of Fenbendazole in Dogs and Cats
When used as labeled, fenbendazole in dogs and cats is generally well tolerated, and side effects are uncommon.
The following side effects in dogs may be seen:
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Allergic reaction (anaphylaxis), including hives, facial swelling, lethargy, trouble breathing, and collapse
Contact your veterinarian if your dog is experiencing stomach upset and seek immediate medical treatment if you suspect your dog may be having an allergic reaction.
A 2000 study demonstrated that fenbendazole is well tolerated in cats and can temporarily cause soft stool, which quickly resolves on its own.
Human Side Effects
Fenbendazole is a prescription veterinary medication not intended for use in humans. Wash your hands after handling this medication.
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. Fenbendazole frequently has dosages different from those prescribed for your pet by a veterinarian.
If you accidentally ingest a pet medication, seek medical attention in person or call Poison Control at 800-222-1222.
Monitoring Your Pet
No specific monitoring is required for this medication, but your veterinarian may recommend routine testing depending on your pets' individual needs, other medications they may be prescribed, and/or the issue that initially caused your pet to be placed on this medication.
When To Call Your Vet
Call your veterinarian if you see any of the following:
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Severe side effects (above)
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Your pet’s condition worsens or does not improve with treatment
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You see or suspect an overdose
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If you have additional questions or concerns about the use of fenbendazole
Fenbendazole Overdose Concerns in Dogs and Cats
A single overdose of fenbendazole in dogs and cats is unlikely to cause toxicity.
Fenbendazole has a wide margin of safety in cats, as demonstrated in a study.
Giving large overdoses of fenbendazole over an extended period in dogs may lead to bone marrow suppression, resulting in abnormally low blood cell counts.
If you suspect an overdose, immediately seek emergency veterinary care or contact an animal poison control center. Consultation fees often apply.
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Pet Poison Helpline 855-764-7661
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ASPCA Animal Poison Control 888-426-4435
How To Store Fenbendazole for Dogs and Cats
Keep the following storage tips in mind for this medication:
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Always confirm storage requirements by reading the prescription label.
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Compounded medications should be stored according to the compounding pharmacy’s label.
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Store this medication at room temperature at or below 77 F (25 C). Do not freeze this medication. Keep the container tightly closed to protect from moisture and light.
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Keep out of reach of children and pets.
Fenbendazole for Dogs and Cats FAQs
How much fenbendazole can I give my dog?
As with any medication, the safest way to know the proper dose for your dog is to ask your veterinarian and follow the directions on the drug label. Your veterinarian will recommend the appropriate dose for your dog depending on their individual needs and weight.
How long does it take for fenbendazole to work for a Giardia infection?
Giardia is a microscopic protozoal parasite that can infect the digestive tract and cause diarrhea in animals and humans. Fenbendazole is one of the medications veterinarians prescribe to treat this infection.
It’s important to closely follow the instructions provided by your veterinarian because it’s possible for Giardia to spread from pets to humans.
Veterinarians typically prescribe fenbendazole for three to five days to treat Giardia, but the length of treatment may vary or even be extended depending on your pet’s response to the medication.
Your veterinarian may also likely recommend a specific bathing program for your pet to prevent reinfection and recommend testing a fecal sample after finishing the medication to ensure that the treatment was successful.
What kind of worms does fenbendazole kill?
Fenbendazole treats roundworms, hookworms, whipworms, and tapeworms in dogs.
Your veterinarian may prescribe fenbendazole to treat other types of parasites, including Giardia and lungworms.
How long does fenbendazole take to work in cats?
Fenbendazole is not FDA-approved for use in cats. However, your veterinarian may prescribe fenbendazole to treat certain types of parasites.
Treatment times vary between parasites. Follow the instructions provided by your veterinarian.
Can I use fenbendazole prescribed for horses on my dog?
No. Use only dog medications in dogs and horse medications in horses. Horse medications are usually much more concentrated than dog medications, making overdoses more likely.
No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.
