Simparica Trio is a prescription-only monthly chewable tablet for dogs available in the United Kingdom, combining three active ingredients—sarolaner, moxidectin, and pyrantel—to provide broad-spectrum parasite protection. The medication is licensed for use in dogs from 8 weeks of age and 1.25 kg bodyweight, targeting fleas, ticks, heartworm, roundworms, hookworms, and the fox lungworm Angiostrongylus vasorum.
Manufactured by Zoetis, the tablet is formulated to be palatable for most dogs and can be administered with or without food. Unlike separate treatments for different parasites, this single chewable offers integrated monthly protection, requiring a veterinary prescription (POM-V) for purchase from UK vets or accredited online pharmacies.
The product has been extensively reviewed by UK regulators, with the Veterinary Medicines Directorate (VMD) publishing a revised Summary of Product Characteristics (SPC) in September 2025. Clinical data submitted to the NOAH Compendium establishes dosing protocols across seven weight bands, from puppies under 2.5 kg to large breeds exceeding 60 kg.
Simparica Trio Dosages for Dogs by Weight
Selecting the correct tablet strength requires accurate bodyweight measurement. The UK licensing specifies minimum recommended doses of 1.2–2.4 mg/kg sarolaner, 0.024–0.048 mg/kg moxidectin, and 5–10 mg/kg pyrantel. Tablets must not be divided, making weight band selection critical for efficacy and safety.
Fleas, ticks (5 types), heartworm, roundworms, hookworms, lungworm
Monthly chewable tablet, palatable formulation
5-10kg, 10-20kg, 20-40kg, 40-60kg, plus smaller/larger brackets
Licensed POM-V, VMD/NOAH listed
Key Facts About Simparica Trio Administration
- Provides 35 days of persistent flea-killing activity, interrupting egg-laying cycles
- Kills five tick species prevalent in the UK before transmission of tick-borne diseases
- Delivers 100% protection against A. vasorum L5 lungworm larvae
- Requires year-round monthly administration for heartworm prevention
- Safe for puppies from 8 weeks old in margin-of-safety studies
- May be given with food or on an empty stomach
Complete Dosage Table by Bodyweight
| Dog Bodyweight | Tablet Strength (sarolaner/moxidectin/pyrantel) | Tablets per Dose |
|---|---|---|
| 1.25–2.5 kg | 3 mg / 0.06 mg / 12.5 mg | 1 |
| >2.5–5 kg | 6 mg / 0.12 mg / 25 mg | 1 |
| >5–10 kg | 12 mg / 0.24 mg / 50 mg | 1 |
| >10–20 kg | 24 mg / 0.48 mg / 100 mg | 1 |
| >20–40 kg | 48 mg / 0.96 mg / 200 mg | 1 |
| >40–60 kg | 72 mg / 1.44 mg / 300 mg | 1 |
| >60 kg | Appropriate combination | Varies |
For dogs weighing over 60 kg, veterinarians must calculate combinations of tablets to achieve the minimum recommended doses. The medication should be administered year-round for heartworm prevention, beginning within one month of anticipated mosquito exposure and continuing for one month after exposure ends.
Simparica Trio for Dogs Side Effects
Clinical studies submitted to US regulators and reviewed by UK authorities indicate that Simparica Trio is generally well-tolerated across breeds, including ivermectin-sensitive Collies. Safety margin studies tested doses up to five times the recommended amount in Beagles and Collies without fatal outcomes, though transient neurological signs appeared in avermectin-sensitive breeds at elevated doses.
Commonly Reported Reactions
Gastrointestinal symptoms represent the most frequently observed adverse events. Vomiting, diarrhea, hypersalivation, and anorexia appear in a minority of treated dogs. Heartworm-positive dogs demonstrate increased frequency of diarrhea when administered three times the standard dose. Most reactions resolve without intervention.
Breed-Specific and Health Considerations
Avermectin-sensitive Collies receiving five times the standard dose exhibited ataxia, muscle fasciculations, and mydriasis, though these symptoms resolved by day three post-administration. Puppies aged 8 weeks and older tolerated margin-of-safety studies at one to five times the dose without significant adverse effects.
Owners must observe their dog for complete consumption of the chewable tablet. If the dog spits out the tablet or appears to have incompletely ingested it, veterinary consultation is necessary before redosing.
Pharmacokinetic Profile
US regulatory data indicates rapid absorption following oral administration, with sarolaner reaching maximum plasma concentration (Cmax) of 523 ng/mL at approximately 3.5 hours post-dose. The VMD SPC does not list UK-specific side effect frequency data, indicating that individual dogs may react differently to the medication.
Simparica Trio for Dogs in the UK
In the United Kingdom, Simparica Trio holds Prescription-Only Medicine, Veterinarian (POM-V) classification. This status means the product cannot be purchased without a valid veterinary prescription, either directly from high-street vets or through accredited online pharmacies such as Animed.
Regulatory Documentation
The product appears in the NOAH Compendium, the authoritative UK database for veterinary medicine particulars, with clinical data dating to 2015. The VMD SPC document, last revised in September 2025, provides the definitive UK licensing information regarding indications, contraindications, and posology.
Supply Sources
Licensed supply channels require a prescription verification process. Online pharmacies offering the medication must display the Royal Pharmaceutical Society accreditation or equivalent, and prescriptions must originate from UK-registered veterinary surgeons who have physically examined the dog within the preceding months.
Simparica Trio for Dogs 20-40kg Price
Specific pricing data for the 20-40kg weight band (48 mg sarolaner / 0.96 mg moxidectin / 200 mg pyrantel tablets) remains commercially sensitive and varies between suppliers. As a POM-V product, prices are not typically advertised publicly without prescription verification processes.
The total cost of treatment includes both the veterinary consultation fee for prescription issuance and the tablet price itself. Some practices offer health plans that include parasite prevention at discounted rates compared to individual monthly purchases.
Comparative shopping between accredited online pharmacies and brick-and-mortar veterinary practices may yield price variations, though the prescription requirement limits the scope for competitive retail pricing seen with non-prescription parasite treatments.
Simparica Trio UK Approval Timeline
The regulatory history of Simparica Trio in the United Kingdom reflects evolving clinical data and periodic safety reviews by the VMD.
- : Initial inclusion in the NOAH Compendium with primary clinical particulars established
- : VMD review cycle updates safety and efficacy documentation
- : Revised SPC published by the VMD, updating administration guidelines and contraindications
This timeline demonstrates ongoing regulatory surveillance typical of combination parasiticide products, with particular attention to neurological safety in herding breeds and efficacy against emerging tick-borne threats.
What Veterinary Sources Confirm About Simparica Trio
Distinguishing between established licensing facts and information gaps helps owners make informed decisions about parasite prevention.
| Established Information | Unclear or Unspecified |
|---|---|
| Efficacy against fleas, ticks, heartworm, roundworms, hookworms, and lungworm | UK-specific side effect frequency percentages |
| Minimum dosages per kg for each active ingredient | Exact retail pricing across weight bands |
| Safety in ivermectin-sensitive Collies at 5x dose | Long-term effects beyond standard trial periods |
| POM-V prescription requirement | Generic availability timelines |
Can I Take Two Fexofenadine 180 mg – Safety and Dosage Guide demonstrates similar regulatory clarity principles applied to human medication safety.
Why Monthly Parasite Protection Matters for UK Dogs
The United Kingdom presents distinct parasite risks requiring year-round vigilance. Angiostrongylus vasorum (fox lungworm) has expanded its geographic range across southern England and Wales, with infection potentially fatal if untreated. Tick species capable of transmitting Lyme disease populate woodland and heathland areas nationwide.
Heartworm, though less prevalent than in southern Europe, requires prevention for dogs traveling abroad or in areas with established mosquito populations. The combination approach in Simparica Trio addresses these multiple threats simultaneously, reducing compliance failure associated with separate monthly treatments.
The product’s ability to kill fleas before egg-laying breaks the household infestation cycle, addressing the environmental component of flea control often missed by purely adulticidal treatments.
Data From UK Veterinary Regulators
Official documentation provides specific efficacy claims based on controlled studies.
“The product provides 100% protection against Angiostrongylus vasorum L5 larvae and kills fleas before they can lay eggs, with persistent activity for at least 35 days.”
— NOAH Compendium, Simparica Trio Summary of Product Characteristics
“Treatment of dogs with existing heartworm infections resulted in increased incidence of diarrhea when administered at 3 times the recommended dose.”
— US Prescribing Information, Zoetis (supporting UK safety profile)
Is Simparica Trio Right for Your Dog?
Simparica Trio offers comprehensive monthly protection suitable for dogs from 8 weeks of age across multiple weight categories, requiring veterinary prescription and weight-accurate dosing. While generally well-tolerated, including in sensitive breeds, owners should monitor for gastrointestinal side effects and ensure complete tablet consumption. Why Do You Have to Increase Mounjaro Dose – Titration Schedule Guide illustrates similar principles of medical dosing precision applicable across species.
Frequently Asked Questions
What is the correct Simparica Trio dosage for a 5-10 kg dog?
Dogs weighing 5–10 kg require the 12 mg sarolaner / 0.24 mg moxidectin / 50 mg pyrantel tablet, administered as a single chewable once monthly.
How should Simparica Trio be given to dogs between 10-20 kg?
The 24 mg / 0.48 mg / 100 mg tablet is indicated for this weight range. Give one chewable monthly, with or without food.
What tablet strength applies to dogs weighing 20-40 kg?
Dogs in the 20–40 kg bracket receive the 48 mg sarolaner / 0.96 mg moxidectin / 200 mg pyrantel tablet monthly.
Can Simparica Trio be used for dogs over 40 kg?
Yes. Dogs 40–60 kg take the 72 mg / 1.44 mg / 300 mg tablet. Dogs exceeding 60 kg require a calculated combination of tablets to achieve minimum recommended doses.
What are the most common side effects in UK dogs?
Vomiting, diarrhea, hypersalivation, and anorexia represent the most frequently reported reactions. Heartworm-positive dogs may experience increased diarrhea.
At what age can puppies start Simparica Trio?
The product is licensed for puppies from 8 weeks of age and 1.25 kg bodyweight.
Does Simparica Trio require a veterinary prescription in the UK?
Yes. It is classified as POM-V (Prescription-Only Medicine, Veterinarian) and cannot be purchased without a valid prescription from a UK-registered vet.
How quickly does Simparica Trio work against fleas?
The product kills fleas before they can lay eggs and maintains persistent activity for at least 35 days.
Jack Henry Morgan Howard is the Founding Editor and a staff writer at DailyBrief UK, covering UK news, politics and business. He works to the newsroom's sourcing and fact-checking standards under Editor-in-Chief Eleanor Whitcombe, so that every briefing is concise, accurate and clearly attributed.