Pyrantel Pamoate
Pyrantel pamoate
Also known as: Strongid T · Strongid Paste · Strongid C · Nemex-2 · Drontal Plus · Heartgard Plus · Tri-Heart Plus · Virbantel · Reese's Pinworm · Pin-X · CP-10423-16 · pyrantel embonate · pirantel pamoate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible parasites | For dogs weighing <5 lb: 10 mg/kg (as base) PO; for dogs weighing >5 lbs: 5 mg/kg (as base) PO. Treat puppies at 2, 3, 4, 6, 8, and 10 weeks of age. Treat lactating bitches 2-3 weeks after whelping. Do follow-up fecal 2-4 weeks after treating to determine need for retreatment. | PO | See dose | — | 🌎 NA |
| For hookworms, or roundworms | 5 mg/kg PO after meals; repeat in 7-10 days | PO | repeat in 7-10 days | — | 🌎 NA |
| Puppies | 5-10 mg/kg PO; can be repeated every 2-3 weeks until at least 12 weeks of age. | PO | every 2-3 weeks | until at least 12 weeks of age | 🌎 NA |
| For susceptible parasites | 20 mg/kg PO; be sure that liquid is well mixed before using; tablets may be broken for accurate dosing. | PO | Single dose | — | 🌎 NA |
- Puppies: Can be treated as early as 2-3 weeks of age
- For susceptible parasites: Not FDA-approved for cats but very safe and effective.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible parasites using combination product with praziquantel (Drontal) | Administer a minimum dose of 2.27 mg praziquantel and 9.2 mg pyrantel pamoate per pound of body weight according to the dosing tables on labeling. | PO | Single dose | — | 🌎 NA |
| Ascarids, Hookworms, Physaloptera | 5 mg/kg, PO; repeat in 2 weeks (one time only for Physaloptera) | PO | repeat in 2 weeks | — | 🌎 NA |
| For susceptible parasites | 10 mg/kg PO, repeat in 3 weeks | PO | repeat in 3 weeks | — | 🌎 NA |
| Kittens | 5-10 mg/kg PO; can be repeated every 2-3 weeks until at least 12 weeks of age. | PO | every 2-3 weeks | until at least 12 weeks of age | 🌎 NA |
- For susceptible parasites using combination product with praziquantel (Drontal): May be given directly by mouth or in a small amount of food. Do not withhold food prior to or after treatment. If reinfection occurs, treatment may be repeated.
- Kittens: Can be treated as early as 2-3 weeks of age
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Rabbits: For susceptible parasites | 15-10 mg/kg PO, repeat in 2-3 weeks | PO | repeat in 2-3 weeks | — | 🌎 NA |
| Llamas: For susceptible parasites | 18 mg/kg, PO for one day | PO | Single dose | 1 day | 🌎 NA |
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Psittacines: In endemic areas, outdoor breeding birds and their offspring should be routinely dewormed for ascarids | 25 mg/kg PO q2 weeks. | PO | q2 weeks | — | 🌎 NA |
| For intestinal nematodes | 100 mg/kg, PO as a single dose in psittacines and passerines | PO | Single dose | — | 🌎 NA |
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible parasites | 6.6 mg/kg PO every 6-8 weeks for ascarid control in foals and every 4 weeks for ascarid control on some farms. For tapeworm control, double the dose (13.2 mg/kg PO) and use once to twice yearly. | PO | every 4-8 weeks or 1-2x yearly | — | 🌎 NA |
| For susceptible parasites | 6.6 mg (as base)/kg PO; 13.2 mg (as base)/kg for cestodes | PO | Single dose | — | 🌎 NA |
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible parasites | Pyrantel tartrate: 25 mg/kg, PO | PO | Single dose | — | 🌎 NA |
Swine
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| To remove Ascaris suum or Oesophagostomum spp. | Pyrantel tartrate: 22 mg/kg PO (or in feed at a rate of 800 grams/ton) as a single treatment. For Ascaris suum only: in feed at a rate of 96 grams/ton (2.6 mg/kg) for 3 days. | PO | Single dose or 3 days | 1-3 days | 🌎 NA |
| For ascarids and nodular worms in potbellied pigs | 6.6 mg/kg PO | PO | Single dose | — | 🌎 NA |
- To remove Ascaris suum or Oesophagostomum spp.: Label instructions from several pyrantel tartrate premix products
Sheep
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible parasites | Pyrantel tartrate: 25 mg/kg, PO | PO | Single dose | — | 🌎 NA |
Goats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible parasites | Pyrantel tartrate: 25 mg/kg, PO | PO | Single dose | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Pyrantel pamoate is a widely used, highly safe pyrimidine anthelmintic primarily effective against luminal nematodes, specifically ascarids (roundworms) and hookworms, across a variety of species.
Because the pamoate salt is poorly absorbed from the gastrointestinal tract, it achieves high concentrations directly in the gut lumen where the target parasites reside. It is a staple in pediatric veterinary medicine (routinely used in puppies and kittens) due to its exceptionally wide margin of safety and availability in palatable liquid suspensions.
Clinical Pearl: While highly effective against roundworms and hookworms, standard doses of pyrantel are ineffective against whipworms (Trichuris spp.) and most tapeworms. In horses, however, a double dose is utilized for the control of the ileocecal tapeworm (Anoplocephala perfoliata). Resistance in equine strongyles and canine hookworms (Ancylostoma caninum) is an emerging clinical concern.
Mechanism of action
Pyrantel acts as a depolarizing neuromuscular blocking agent in susceptible parasites.
- It binds selectively to nicotinic acetylcholine receptors on the somatic muscle cells of the nematode.
- This binding causes continuous depolarization and an influx of calcium → spastic paralysis of the worm.
- Paralyzed worms lose their ability to maintain attachment to the host's intestinal mucosa and are subsequently expelled alive in the feces via normal gastrointestinal peristalsis.
- It also possesses mild cholinesterase inhibitory properties, further contributing to the accumulation of acetylcholine at the parasite's neuromuscular junction.
Safety & warnings
Contraindications
- Severely debilitated animals
Adverse effects
- Emesis (rare, primarily in small animals)
Precautions
Use with caution in severely debilitated animals. The drug is considered very safe for use during pregnancy (Class A in dogs/cats) and is safe to use in nursing veterinary patients.
Drug interactions
Increased risk for adverse effects
Because of similar mechanisms of action (and toxicity), do not use concurrently
Because of similar mechanisms of action (and toxicity), do not use concurrently
Increased risk for adverse effects
Pyrantel and piperazine have antagonistic mechanisms of action; do not use together
Monitoring
- Fecal egg count reduction testing (FECRT) for strongyle nematodes (especially in horses to monitor for resistance)
- Resolution of clinical signs of parasitism
- Routine fecal flotations 2-4 weeks post-treatment
Pharmacokinetics
Absorption
Pyrantel pamoate is poorly absorbed from the GI tract, allowing it to reach the lower GI in dogs, cats, and equines. Pyrantel tartrate is absorbed more readily than the pamoate salt. Pigs and dogs absorb pyrantel tartrate more so than ruminants, with peak plasma levels occurring 2-3 hours after administration.
Distribution
Acts primarily locally within the gastrointestinal lumen due to poor systemic absorption of the pamoate salt.
Metabolism
The fraction of the drug that is absorbed is rapidly metabolized.
Elimination
Excreted into the urine and feces.
Overdose
Pyrantel has a moderate to wide margin of safety.
- Dosages up to approximately 7 times the recommended dose generally result in no toxic reactions.
- In horses, doses of 20X yielded no adverse effects.
- The LD50 in mice and rats for pyrantel tartrate is 170 mg/kg; >690 mg/kg for pyrantel pamoate in dogs.
- Chronic dosing of pyrantel pamoate in dogs resulted in clinical signs when given at 50 mg/kg/day, but not at 20 mg/kg/day over 3 months.
- Clinical signs of toxicity may include increased respiratory rates, profuse sweating (in species with sweat glands), ataxia, or other cholinergic effects.
Available products
Formulations
- Tablets
- Oral suspension
- Oral paste
- Top dress (granules/pellets)
- Soft-gel capsules
Veterinary
- Pyrantel Pamoate Tablets: 22.7 mg, 113.5 mg (Nemex Tabs)
- Pyrantel Pamoate Oral Suspension: 4.54 mg/mL (Nemex-2)
- Pyrantel Pamoate Oral Suspension: 50 mg/mL (Strongid T)
- Pyrantel Pamoate Oral Paste: 43.9% w/w (180 mg/mL) (Strongid Paste)
- Pyrantel Tartrate 1.06% Top Dress: 4.8 grams/lb (Strongid C)
- Combination Tablets: Praziquantel/Pyrantel pamoate (Drontal for Cats)
- Combination Chewables: Praziquantel/Pyrantel pamoate (Virbantel)
- Combination Tablets: Praziquantel/Pyrantel pamoate/Febantel (Drontal Plus for Dogs)
- Combination Chewables: Ivermectin/Pyrantel (Heartgard Plus, Tri-Heart Plus)
Human-labeled
- Pyrantel Pamoate Oral Suspension: 50 mg/mL & 144 mg/mL (Reese's Pinworm, Pin-X)
- Pyrantel Soft-gel Oral Capsules: 180 mg (Pin-Rid, Reese's Pinworm)
- Pyrantel Pamoate Oral Tablets: 180 mg & 720.5 mg chewable (Reese's Pinworm, Pin-X)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Pyrantel pamoate products should be stored in tight, light-resistant containers at room temperature (15-30°C) unless otherwise directed by the manufacturer.
Client information
- Shake liquid suspensions thoroughly before drawing up the dose, as the medication settles at the bottom of the bottle.
- Can be given directly by mouth or mixed into a small amount of food. You do not need to withhold food before or after giving this medication.
- You may see intact, dead, or dying worms in your pet's stool within 24-48 hours after administration. This is normal and indicates the medication is working.
- This medication is extremely safe, even for very young puppies and kittens. Side effects are very rare, though occasional vomiting may occur.
- Follow your veterinarian's schedule for repeat dosing, as a single dose does not kill migrating larval stages of the parasites.
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.