Panacur Side Effects

By Tammy Dray

Panacur is a canine dewormer whose side effects appear to be relatively minimal. However, as in the case of many prescription drugs, it is possible that any individual dog might develop side effects when using panacur. Contact your veterinarian at once if you observe changes in behavior or appearance in your dog after taking Panacur.

Prescription Worm Killer

Panacur is the brand name for fenbendazole, a drug used to kill roundworms, whipworms, hookworms and some tapeworms. Panacur, approved for dogs and other small animals, is available only via prescription. It may be dispensed in granule form or as an oral suspension; you can mix it with food. The drug can't prevent reinfection, so your vet will advise you on proper preventive care.

Side Effects Are Rare

Side effects of Panacur are rare, and they tend to be mild. The Doctors Foster and Smith website's Patient Information Sheet says, "Fenbendazole is a very safe drug. Adverse reactions and toxicities are unlikely." The most common side effect is vomiting, which occurs in about 1 percent of dogs administered Panacur. Panacur has no known drug or food interactions.

Allergic Reactions

Although Panacur is considered safe, allergic reactions can occur. If you notice any signs of allergic reaction, take your dog to the vet immediately for treatment. The Doctor's Foster and Smith Patient Information Sheet for Panacur/fenbendazole says signs of an allergic reaction include facial swelling, intense and sudden scratching and hives, seizures and cold limbs. Dogs suffering an allergic reaction to Panacur might also have pale gums and sudden diarrhea. They might also go into shock.

Contraindications and Risks

Panacur overdoses are rare. Tell your vet about any medications or supplements your dog is taking, and whether he has had an allergic reaction to any medication in the past. Your dog must take Panacur for three to five days in a row for the drug to be effective. Your vet will advise you.