Panacur(®) is an FDA approved veterinary dewormer containing the active ingredient fenbendazole. It is most often used to remove hookworm, roundworm, tapeworm (Taenia) and whipworm. It is not effective against Dipylidium tapeworm infections.
It is able to kill parasites by damaging tubulin and intefering with the formation of microtubules. At higher doses it also disrupts metabolic enzymes and metabolic pathways. The medicine is sometimes used off-label to treat Giardia and lungworm infections.
Please speak to your vet before using this medicine. Your vet may recommend an altered dosage when treating Giardia or lungworm.
Intervet, the medicine’s manufacturer, recommends the routine use of fenbendazole at 100 mg/kg (around 45.4 mg/lb) as a single dose for adult dogs, and 50 mg/kg (around 22.7 mg/lb) for three days for weaned puppies under six months of age. The medicine is available in the form of granules, a liquid suspension, and a paste.
The Panacur C packaging recommends a daily dose of 50 mg/kg (which is about 1 gram of product for every 10 pounds your dog weighs) to be given for three consecutive days. This product is sold in 1, 2 and 4 gram sachets, with each gram containing 222 mg of fenbendazole.
|Weight of dog (lbs)||Sachets required (per dose)|
|10||One 1 gram sachet daily|
|20||One 2 gram sachet daily|
|30||One 2 gram sachet + one 1 gram sachet daily|
|40||One 4 gram sachet daily|
|50||One 4 gram sachet + one 1 gram sachet daily|
|60||One 4 gram sachets + one 2 gram sachets daily|
|70||One 4 gram sachets + one 2 gram sachet + one 1 gram sachet daily|
|80||Two 4 gram sachets daily|
|90||Two 4 gram sachets + one 1 gram sachet daily|
|100||Two 4 gram sachets + one 2 gram sachet daily|
|Over 100||Use an appropriate combination|
Traditionally the 1 g sachets come in the yellow box, the 2 g sachets in the green box, and the 4 g sachets in the orange box.
When using the oral suspension you can choose to use the 2.5% or 10% solution. It’s a good idea to use the 2.5% solution for small dogs to lower the risk of accidental overdose. For medium and large dogs the 10% Safe-Guard dewormer for goats (which can be purchased here) can be used and is more cost effective.
|Concentration||Adult dog dosage||Puppy (under 6 months old) dosage|
|2.5%||4 mL/kg (~1.82 mL/lb)||2 mL/kg (~0.9 mL/lb)|
|10%||1 mL/kg (~0.45 mL/lb)||0.5 mL/kg (~0.23 mL/lb)|
For routine treatment, doses may be given every 3 to 4 months for most dogs or every 6 to 8 weeks for those in kennels. The puppy dose is to be given for three days in a row.
Larger Adult Dogs: Intervet recommends an extra 1 mL of 10% suspension for every additional kilogram a dog weighs over 64 kg. For example, a 70 kg dog would be given 70 mL + 6 mL for a total dosage of 76 mL. For the 2.5% concentration, an additional 4 mL for every kilogram a dog weighs over 64 kg is advised.
Larger Puppies: An extra 0.5 mL of 10% suspension or an extra 2 mL of 2.5% suspension for every kilogram a puppy (under 6 months of age) weighs over 10 kg is advised. As an example, an 11 kg puppy would need 5.5 mL of 10% oral suspension (5 mL + 0.5 mL) or 22 mL of 2.5% oral suspension.
Pregnant Dogs: A slightly altered dosage of 25 mg/kg fenbendazole may be used when treating pregnant dogs. You should give 0.25 mL/kg per dose when using the 10% suspension and 1 mL/kg when using the 2.5% suspension.
To find your dog’s weight in kilograms, simply divide their weight in pounds by 2.2 or use the calculator below.
Panacur 18.75% Oral Paste
Panacur oral paste comes in the form of a 5 g syringe which contains 187.5 mg of fenbendazole for every gram of product (an 18.75% concentration). To use the paste you should squeeze the product onto the back of your dog’s tongue after they have eaten a meal. The dosage is 2 syringe graduations for each kilogram in adult dogs or 1 syringe graduation per kilogram in puppies. These doses are to be given at the usual intervals.
We recommend sticking to the paste created for dogs as it’s much easier to work out and administer the correct amount.
Is It Safe For Dogs?
Fenbendazole is one of the safest dewormers available. In fact, doses up to 100x higher than usual are apparently well tolerated by dogs. While other parasite medicines like ivermectin have been associated with many risks (particularly in herding breeds), fenbendazole appears to cause few side effects. The main risk of treating dogs with this drug is the potential reactions to the dying parasites in the body. It is safe for most puppies as long as they are over 6 weeks old and also for pregnant dogs though an altered dose may be recommended and you should not use the paste (please consult with your vet about this).
Stick to the plain Panacur formulation whenever possible and do not administer the drug alongside bromsalan flukicides.
FDA: Fenbendazole is approved by the FDA for veterinary use in various forms including the oral suspension and granules. This can be verified by searching for “fenbendazole” on the FDA website.
To safely use this medicine we recommend following our guidelines:
- Do not use this medicine without the recommendation of your vet
- Notify the vet if your dog is taking any other medicines or supplements
- Tell the vet about any medical conditions your dog suffers from
- Administer liquid doses with food or directly after feeding
- Do not give the paste to a pregnant or lactating dog
- Only give this medicine to dogs over 6 weeks of age
- Avoid use on very sick or debilitated dogs
Remember to use the product for 3 consecutive days as single doses are not effective, even when unusually large amounts of product are used. It’s best to avoid giving the “Plus” formulation to herding breeds, Longhaired Whippets, Silken Windhounds or Skye Terriers due to the higher risk of adverse reactions. Some mixed breeds may also be at a higher risk of side effects.
This medicine can be used to treat:
- Tapeworm (Taenia)
The treatment of Giardia and lungworm with fenbendazole is off-label but becoming more popular. For treating fleas Panacur is not effective, instead you should try Bravecto.
Whipworm Notice: Though fenbendazole clears up Trichuris vulpis (whipworm) infections, the eggs can remain viable for up to 7 years. For this reason it’s a good idea to start using a preventative medicine to stop the infection from returning.
Potential Side Effects
When using the plain formula with fenbendazole as the sole active ingredient, side effects are not expected, but pancytopenia (a decrease in the number of red and white blood cells) and vomiting have been reported in rare cases.
When using the “Plus” formulation, additional side effects are possible including:
- Loss of appetite
- Elevated heart rate
- Slowed heart rate
- Loss of coordination
- Vision problems
If you notice any serious side effects following the use of this medicine you should immediately get in contact with a veterinary professional.
Plumb’s Veterinary Drug Handbook (sixth edition)
The Merck Veterinary Manual