Praziquantel
Prazinoisoquinoline derivative
Also known as: Droncit · Drontal Plus · Profender · Quest Plus · Equimax · Zimecterin Gold · Virbantel · Panacur Plus · Biltricide · Milbemax · Broadline · Milpro · EMBAY-8440 · praziquantelum · Bio-Cest · Cercon · Cesol · Cestox · Cisticid · ComboCare · Cysticide · Ehliten · Extiser Q · Mycotricide · Opticide · Praquantel · Prasikon · Prazite · Prozitel · Sincerck · Teniken · Waycital · Zifartel · PZQ
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidencePraziquantel as a single agent (extra-label) — Alaria spp
Verified clinician required
Alternative schedules — select one
- once
- q24h · for 2 to 10 days
NA
Governing clinical context (4)
- NOTE: For dosages of other combination products that contain praziquantel, see Emodepside/Praziquantel, Eprinomectin/ Praziquantel, Ivermectin, Lufenuron, Milbemycin Oxime, Moxidectin/Moxidectin Combination Products, and Pyrantel.
- Praziquantel as a single agent (extra-label):
- ■ This medicine can be given with or without food. The tablets may be crushed or mixed with food. Your animal does not need to have food withheld prior to treatment.
- Unless otherwise instructed by the manufacturer, praziquantel tablets should be stored in tight containers at room temperature (25°C Products [77°F]). Protect from light. Praziquantel injection should be stored at or below 25°C (77°F) and not allowed to freeze. Vials of praziquantel injection should be used within 6 months of first vial puncture and discarded after a maximum number of punctures (10 mL vial, 25 times; 50 mL vial, 90 times).
Praziquantel as a single agent (extra-label) — Adjunctive treatment of flukes (Nanophyetus salmincola) associated with Salmon poisoning
Verified clinician required
- once
NA
Governing clinical context (4)
- NOTE: For dosages of other combination products that contain praziquantel, see Emodepside/Praziquantel, Eprinomectin/ Praziquantel, Ivermectin, Lufenuron, Milbemycin Oxime, Moxidectin/Moxidectin Combination Products, and Pyrantel.
- Praziquantel as a single agent (extra-label):
- ■ This medicine can be given with or without food. The tablets may be crushed or mixed with food. Your animal does not need to have food withheld prior to treatment.
- Unless otherwise instructed by the manufacturer, praziquantel tablets should be stored in tight containers at room temperature (25°C Products [77°F]). Protect from light. Praziquantel injection should be stored at or below 25°C (77°F) and not allowed to freeze. Vials of praziquantel injection should be used within 6 months of first vial puncture and discarded after a maximum number of punctures (10 mL vial, 25 times; 50 mL vial, 90 times).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Praziquantel is a highly effective, broad-spectrum anticestodal (tapeworm) and antitrematodal (fluke) anthelmintic widely used in veterinary medicine.
Key clinical features include:
- Broad Spectrum: Highly effective against major tapeworm species including Dipylidium caninum, Taenia spp., and Echinococcus spp. in dogs and cats.
- Trematode Efficacy: Also utilized off-label for various fluke infections (e.g., Paragonimus kellicotti, liver flukes).
- High Safety Margin: Generally very safe, though injectable formulations may cause transient local pain or mild systemic signs.
- Combination Therapy: Frequently combined with other parasiticides (like pyrantel, febantel, ivermectin, or moxidectin) to provide comprehensive internal parasite control.
Clinical Pearl: Because praziquantel damages the parasite's tegument, the worms are typically digested by the host. Therefore, intact tapeworms are rarely observed in the feces following successful treatment.
Mechanism of action
Praziquantel's exact mechanism is not fully elucidated, but it rapidly penetrates the parasite and alters the permeability of the cell membranes.
- Ion Flux Alteration: Interacts with phospholipids in the parasite's integument → induces rapid intracellular influx of calcium ions (Ca2+), as well as sodium and potassium fluxes.
- Spastic Paralysis: The sudden calcium influx causes severe, sustained contraction and spastic paralysis of the worm's musculature, impairing sucker function and dislodging the parasite.
- Tegumental Destruction: At higher concentrations, it causes irreversible focal vacuolization → subsequent disintegration of the cestodal integument. This exposes the parasite's internal antigens to the host's immune system and renders it susceptible to digestion by host enzymes.
- Trematodes: Directly kills the parasite via similar calcium-mediated focal vacuolization and subsequent phagocytosis.
Safety & warnings
Contraindications
- Puppies less than 4 weeks old (for solo product)
- Kittens less than 6 weeks old (for solo product)
- Known hypersensitivity to praziquantel
- Unweaned puppies or kittens (unlikely to be affected by tapeworms at this age)
- Animals weighing < 1 kg (specifically for spot-on preparations)
Adverse effects
- Oral (uncommon, <5%): Anorexia, vomiting, lethargy, diarrhea, salivation (cats)
- Injectable (dogs): Pain at injection site, vomiting, drowsiness, staggering gait
- Injectable (cats): Diarrhea, weakness, vomiting, salivation, sleepiness, transient anorexia, pain at injection site
- Diarrhoea
- Transient hypersalivation (if spot-on application site is licked)
- Localized tissue sensitivity and pain at injection site (particularly in cats)
Precautions
Age Restrictions: The manufacturer recommends not using solo praziquantel in puppies < 4 weeks or kittens < 6 weeks. However, some combination products (e.g., with febantel) are FDA-approved for puppies and kittens of all ages. Pregnancy: Considered safe to use in pregnant dogs and cats (Papich Class A). Nursing: Appears in maternal milk at ~25% of maternal serum concentration, but is unlikely to pose harm to nursing offspring.
Drug interactions
Reportedly synergistic activity occurs in humans in the treatment of schistosomiasis; clinical implications in veterinary patients are unclear.
Can increase the area under the curve (AUC) of orally administered praziquantel by 150-200% in dogs.
Concurrent administration may significantly decrease serum praziquantel concentrations.
May decrease the metabolic clearance of praziquantel, increasing its serum levels.
Monitoring
- Clinical efficacy (resolution of parasite infection)
- Fecal examination for tapeworm proglottids or eggs to confirm efficacy of treatment
- Monitoring for resolution of clinical signs (e.g., scooting, visible segments in feces)
Pharmacokinetics
Half-life
Absorption
Rapidly and nearly completely absorbed after oral administration, but undergoes a significant first-pass effect. Peak serum levels are achieved between 30-120 minutes in dogs.
Distribution
Distributed widely throughout the body. It crosses the intestinal wall and penetrates the blood-brain barrier (BBB) into the CNS.
Metabolism
Metabolized extensively in the liver via CYP3A enzymes to metabolites of unknown activity.
Elimination
Excreted primarily in the urine.
Overdose
Praziquantel has a wide margin of safety.
- Rodents: Oral LD50 is at least 2 g/kg in rats and mice.
- Dogs: An oral LD50 could not be determined because doses >200 mg/kg induce vomiting. In ASPCA APCC reports, dogs exposed to overdoses showed no clinical signs.
- Cats: Parenteral doses of 50-100 mg/kg caused transient ataxia and depression. Injected doses at 200 mg/kg were lethal. In ASPCA APCC reports, a minority of exposed cats showed clinical signs.
Treatment: Overdoses are generally self-limiting (especially oral, due to vomiting). Provide supportive care if severe neurological or gastrointestinal signs occur.
Available products
Formulations
- Chewable tablets
- Injection (solution)
- Oral gel
- Oral paste
- Oral tablets: 10 mg, 20 mg, 25 mg, 30 mg, 40 mg, 50 mg, 125 mg, 144 mg, 150 mg, 175 mg
- Topical spot-on pipettes: 20 mg, 25 mg, 30 mg, 60 mg, 75 mg, 96 mg
- Injectable solution (implied by adverse reactions profile)
Veterinary
- Praziquantel Tablets: 23 mg (feline); 34 mg (canine) (Droncit)
- Praziquantel Injection: 56.8 mg/mL in 10 mL and 50 mL vials (Droncit)
- Combination Tablets: Praziquantel/pyrantel pamoate (Drontal)
- Combination Chewable Tablets: Praziquantel/pyrantel pamoate (Virbantel)
- Combination Chewable Tablets: Fenbendazole/Ivermectin/Praziquantel (Panacur Plus Soft Chews)
- Combination Tablets: Praziquantel/pyrantel pamoate/febantel (Drontal Plus)
- Combination Oral Gel: Moxidectin 20 mg/mL / Praziquantel 125 mg/mL (Quest Plus, ComboCare)
- Combination Oral Paste: Ivermectin 1.87% / Praziquantel 14.03% (Equimax)
- Combination Oral Paste: Ivermectin 1.55% / Praziquantel 7.75% (Zimecterin Gold Paste)
- Drontal (combination)
- Milbemax (combination)
- Profender Spot-on (combination)
- Broadline Spot-on (combination)
- Milpro (combination)
- Cazitel
- Cestem
- Dolpac
- Endoguard
- Veloxa
Human-labeled
- Praziquantel Oral Tablets (Film-coated): 600 mg (Biltricide)
- Biltricide 600 mg tablets
Regulatory status
Classification varies by formulation and combination (POM-V, NFA-VPS, AVM-GSL).
Available under POM-V, NFA-VPS, and AVM-GSL categories depending on the specific product and combination.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Unless otherwise instructed by the manufacturer, praziquantel tablets should be stored in tight containers at room temperature. Protect from light.
Client information
Important Information for Pet Owners
- Administration: You can give this medication with or without food. Fasting is not required before dosing. Tablets may be crushed or mixed with a small amount of tasty food to make it easier to give.
- What to Expect: It is completely normal not to see dead worms in your pet's stool after treatment. Praziquantel causes the tapeworms to disintegrate, and they are usually digested by your pet's body.
- Preventing Reinfection: A single dose is usually highly effective at clearing the current infection. However, tapeworms (especially Dipylidium caninum) are transmitted by fleas. Strict flea control is essential to prevent your pet from getting tapeworms again. If your pet hunts or eats rodents, they may also be at risk for reinfection.
- Side Effects: Side effects are rare when given by mouth but can occasionally include mild vomiting, drooling (especially in cats), lethargy, or diarrhea. If your pet received an injection, they might experience temporary pain at the injection site.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.