# Pyrantel (pamoate) for Animals: Mechanism, Doses by Species & Brands

> Pyrantel is a tetrahydropyrimidine anthelmintic. In Heartgard Plus it is given to dogs at a minimum of 5 mg/kg (as pamoate) once a month against roundworms and hookworms.

- Source page: https://wevet.in/active-ingredients/pyrantel-pamoate/
- Type: Active ingredient
- Publisher: WeVet
- Updated: 2026-11-02
- Medically reviewed by: Dr. Ravi Baraiya, B.V.Sc. (2026-11-02)
- Audience: veterinarians and veterinary students

Pyrantel is a tetrahydropyrimidine anthelmintic [1]. In Heartgard Plus it is given to dogs at a minimum of 5 mg/kg (as pamoate) once a month against roundworms and hookworms [2].

- Class: Tetrahydropyrimidine anthelmintic
- Brands: Heartgard Plus

## Dose by species

| Species | Use | Dose | Route | How often | Basis |
|---|---|---|---|---|---|
| Dogs | Roundworms and hookworms (as Heartgard Plus) (Minimum dose; as pamoate salt.) | 5 mg/kg [2] | PO | Once a month | Label |

## Uses

- Dogs: roundworms (Toxocara canis, Toxascaris leonina) and hookworms, with ivermectin in Heartgard Plus [2].

## Mechanism of action

Tetrahydropyrimidines (pyrantel, oxantel, morantel) are highly potent cholinergic agonists that cause paralysis through their effect at nicotinic receptors [1].


## Frequently asked questions

### How does pyrantel work?

It is a cholinergic agonist that paralyses worms by acting at nicotinic receptors [1].

## References

[1] Pharmacodynamics: Mechanisms of Anthelmintic Action in Animals — Merck Veterinary Manual — E. Claerebout & C. E. Lanusse (Apr 2025) (2025). https://www.merckvetmanual.com/pharmacology/anthelmintics/pharmacodynamics-mechanisms-of-anthelmintic-action-in-animals
[2] HEARTGARD PLUS (ivermectin and pyrantel pamoate) chewable — label — DailyMed (US NLM) — FDA-approved label, Boehringer Ingelheim (2026). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=595a4883-6b37-4190-9579-a2c7ca4738eb

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Numbers in [brackets] cite the references above. For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.
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