Brand Name: Droncit, Interceptor Plus, Milbemax, Profender, Drontal, Drontal Plus, Sentinel Spectrum, Iverhart Plus, Virbantel, Iverhart Max, Credelio Quattro, and Nexgard Combo

Available as injectable; 23 mg tablets for cats and 34 mg tablets for dogs; as a topical dewormer combined with emodepside; numerous products, both topical and oral, are available, combining praziquantel with flea control and other worm control.

How this Medication is Used 

A member of the Taenia genus of tapeworms. Photo courtesy of CDC.

Praziquantel is primarily used against parasites known as cestodes (tapeworms). The common tapeworm of dogs and cats, Dipylidium caninum, is the usual target of this medication although praziquantel is also effective against less common types of tapeworms such as Taenia species and the more dangerous Mesocestoides species and Echinococcus species. Praziquantel is also effective against flukes.

A single treatment of praziquantel should clear a Dipylidium caninum infection although a second treatment is sometimes recommended if it is felt that immediate re-infection is likely. Immediate re-infection might take place if a heavy uncontrolled flea problem is present in the pet's environment. Dipylidium caninum is contracted when an infected adult flea harboring a tapeworm larva is eaten. Taenia tapeworms typically come from the consumption of raw meats or prey.

Praziquantel is also available in combination with other single use oral dewormers as well as with more comprehensive monthly worm protection products. (Numerous brands are available. See the list above.) Such products provide regular deworming against assorted worm parasites. Plain praziquantel is available in non-prescription tablets that may be purchased at pet supply stores. Brand name products, combination products as described above, and injections are available only through veterinarians as they are prescription drugs.

As of late 2007, praziquantel is also available in a topical combination with the anti-parasite drug emodepside. This combination product is applied to the cat's shoulder area and is effective against the tapeworms of the above types as well as hookworms (Ancylostoma tubaeformae) and roundworms (Toxocara cati). The brand name of this product is Profender®; it is manufactured by Elanco and is available by prescription. Nexgard Combo®, made by Boehringer Ingelheim, is a topical feline product combining a flea and tick-killing ingredient, a broad-spectrum dewormer, and praziquantel. It is effective against tapeworms, roundworms, hookworms, heartworms, fleas, and ticks. It is also a prescription product.

Praziquantel is available in non-prescription tablets that may be purchased at pet supply stores. Brand-name products, combination products, and injections are available only through veterinarians as prescription drugs.

How this Medication Works 

Praziquantel acts by damaging the parasite's skin internally such that the parasite disintegrates and is removed by the host's immune system. Unlike the situation with roundworms, dead tapeworms generally will not be seen passing from the host after deworming.

Side Effects 

Injectable praziquantel tends to sting more than most injections, and it is not unusual for a pet to scratch at the site or express discomfort immediately following injection.

The oral form of praziquantel tastes bitter, and approximately 5% of patients taking it experience nausea.

It has been reported that approximately one cat in ten will experience weakness, salivation, or nausea after a tapeworm injection with praziquantel, but such reactions have been seen far less frequently. This is generally of minor significance and resolves on its own.

Adult Dipylidium. The segments are easily seen. The thick end is the tail, where segments drop off. Photo courtesy CDC.

Interactions with Other Drugs

The following medications can increase the blood levels of praziquantel: cimetidine (an antacid), ketoconazole (an antifungal), and itraconazole (another antifungal).

Cautions and Concerns 

Praziquantel is felt to be safe for use in pregnant patients.

Praziquantel should not be used in puppies under four weeks of age or kittens under the age six weeks. The topical Profender product described above is approved for feline use only and is not approved for kittens under eight weeks of age.

Fasting is not necessary prior to praziquantel use, and oral praziquantel can be given with or without food.

Tablets should be stored at room temperature, away from light exposure.