Credelio Quattro for Dogs: Complete Medication Guide
Learn everything about Credelio Quattro for dogs—uses, dosage, side effects, cost, and safety. A vet-informed guide for pet owners.
What Is Credelio Quattro for Dogs?
Credelio Quattro is a prescription-only, chewable tablet designed to protect dogs from multiple parasites with a single monthly dose. Manufactured by Elanco Animal Health, this broad-spectrum parasiticide combines four active ingredients to target external parasites (fleas and ticks) and internal parasites (heartworm, roundworms, hookworms, and whipworms). It represents a newer generation of all-in-one parasite prevention that aims to replace the need for separate heartworm, flea/tick, and deworming products.
Unlike its predecessor Credelio (lotilaner only, which targets fleas and ticks), Credelio Quattro expands protection to include heartworm disease prevention and intestinal parasite control. This makes it a comprehensive option for dog owners seeking simplified parasite management.
Drug Class and Mechanism of Action
Active Ingredients
- Lotilaner: An isoxazoline class insecticide/acaricide that targets the nervous system of fleas and ticks by inhibiting GABA-gated chloride channels, causing parasite death
- Moxidectin: A macrocyclic lactone that prevents heartworm disease by eliminating larval stages of Dirofilaria immitis
- Pyrantel (as pamoate): A tetrahydropyrimidine that paralyzes intestinal nematodes (roundworms and hookworms) through nicotinic acetylcholine receptor stimulation
- Praziquantel: An anthelmintic that causes severe spasms and paralysis of tapeworm musculature, leading to parasite death and digestion
How It Works
Each active ingredient targets specific parasite classes through distinct mechanisms. Lotilaner is absorbed systemically and kills fleas and ticks when they bite the treated dog. Moxidectin circulates in the bloodstream and eliminates heartworm larvae (L3 and L4 stages) before they mature into adults. Pyrantel acts locally in the gastrointestinal tract to expel roundworms and hookworms. Praziquantel damages tapeworm tegument and induces muscular paralysis.
FDA-Approved Uses and Off-Label Applications
FDA-Approved Indications
According to the FDA's animal drug database, Credelio Quattro is approved for:
- Prevention of heartworm disease caused by Dirofilaria immitis
- Treatment and control of adult hookworm (Ancylostoma caninum), roundworm (Toxocara canis), and whipworm (Trichuris vulpis) infections
- Treatment and control of tapeworm (Dipylidium caninum, Taenia pisiformis, Echinococcus granulosus) infections
- Killing adult fleas (Ctenocephalides felis) and treatment/control of flea infestations
- Treatment and control of tick infestations including Amblyomma americanum (Lone Star tick), Rhipicephalus sanguineus (Brown dog tick), Ixodes scapularis (Black-legged tick), and Dermacentor variabilis (American dog tick)
Common Off-Label Uses
Veterinarians may prescribe Credelio Quattro off-label for:
- Prevention of tick-borne disease transmission by rapidly killing ticks before pathogen transfer (typically within 24-48 hours of attachment)
- Management of flea allergy dermatitis (FAD) as part of a comprehensive treatment plan
- Parasite control in multi-dog households where simplified dosing improves compliance
Typical Dosage Range by Condition and Dog Weight
| Dog Weight (lb) | Dog Weight (kg) | Tablet Strength | Active Ingredients per Tablet |
|---|---|---|---|
| 4.4 - 10 | 2.0 - 4.5 | Small | Lotilaner 56 mg / Moxidectin 5 mcg / Pyrantel 56 mg / Praziquantel 19 mg |
| 10.1 - 20 | 4.6 - 9.1 | Medium | Lotilaner 112 mg / Moxidectin 10 mcg / Pyrantel 112 mg / Praziquantel 38 mg |
| 20.1 - 40 | 9.2 - 18.1 | Large | Lotilaner 225 mg / Moxidectin 20 mcg / Pyrantel 225 mg / Praziquantel 75 mg |
| 40.1 - 80 | 18.2 - 36.3 | Extra Large | Lotilaner 450 mg / Moxidectin 40 mcg / Pyrantel 450 mg / Praziquantel 150 mg |
| 80.1 - 132 | 36.4 - 60.0 | XXL | Lotilaner 675 mg / Moxidectin 60 mcg / Pyrantel 675 mg / Praziquantel 225 mg |
Dosage frequency: One chewable tablet administered orally once monthly (every 30 days) year-round for continuous parasite protection.
Minimum age: Safe for puppies 8 weeks of age and older.
Minimum weight: Dogs must weigh at least 4.4 lb (2.0 kg).
Administration Instructions
How to Give Credelio Quattro
- With or without food: Credelio Quattro can be administered with or without food. However, giving with a small meal may reduce the chance of gastrointestinal upset.
- Chewable format: Most dogs accept the flavored chewable tablet willingly. If your dog refuses, you can hide it in a small amount of food or pill pocket.
- Complete consumption: Ensure your dog consumes the entire tablet. If vomiting occurs within 1 hour of administration, contact your veterinarian about redosing.
- Monthly schedule: Administer on the same date each month. Set calendar reminders or use your veterinary clinic's reminder system.
- Duration: Year-round administration is recommended in most regions. In areas with seasonal parasite risk, your veterinarian will advise on the appropriate start and stop dates.
Side Effects: What to Watch For
| Side Effect | Frequency | Severity | Typical Onset |
|---|---|---|---|
| Vomiting | 2-5% of dogs | Mild | Within 24 hours |
| Diarrhea | 1-3% of dogs | Mild | Within 24-48 hours |
| Decreased appetite | 1-2% of dogs | Mild | Within 24 hours |
| Lethargy | <2% of dogs | Mild | Within 24 hours |
| Itching/skin irritation | <1% of dogs | Mild | Within 48 hours |
| Seizures/tremors | Rare (<0.1%) | Serious | Within 24-72 hours |
| Ataxia (loss of coordination) | Rare (<0.1%) | Serious | Within 24-72 hours |
Serious Side Effects Requiring Immediate Veterinary Attention
- Seizures or muscle tremors
- Loss of coordination or inability to stand
- Severe vomiting (more than 2 episodes in 24 hours)
- Bloody diarrhea
- Difficulty breathing
- Facial swelling or hives (signs of allergic reaction)
- Extreme lethargy or unresponsiveness
Isoxazoline Class Warning
Lotilaner belongs to the isoxazoline drug class, which has been associated with neurologic adverse reactions including muscle tremors, ataxia, and seizures in some dogs. According to the FDA's safety communication, these events have occurred in dogs with or without a history of neurologic disorders. Use with caution in dogs with pre-existing seizure disorders or other neurologic conditions.
Contraindications: Dogs Who Should NOT Receive Credelio Quattro
Credelio Quattro is contraindicated or should be used with extreme caution in:
- Puppies under 8 weeks of age: Safety has not been established in very young puppies
- Dogs under 4.4 lb (2.0 kg): Below the minimum weight threshold for safe dosing
- Dogs with known hypersensitivity: Any dog with a history of allergic reaction to lotilaner, moxidectin, pyrantel, praziquantel, or any other isoxazoline class drug
- Heartworm-positive dogs: Dogs must be tested for heartworm infection before starting Credelio Quattro. Administering to a heartworm-positive dog can cause severe reactions
- Dogs with seizure disorders: Use only under close veterinary supervision due to isoxazoline class neurologic risk
- Collie breeds and MDR1 gene mutation carriers: While moxidectin is generally safer than ivermectin, dogs with the MDR1 gene mutation (common in Collies, Australian Shepherds, and related breeds) may have increased drug sensitivity. Genetic testing or caution is advised
- Pregnant or lactating dogs: Safety has not been fully established; consult your veterinarian
Drug Interactions
Medications That May Interact with Credelio Quattro
| Drug Class | Examples | Interaction Risk |
|---|---|---|
| Other macrocyclic lactones | Ivermectin, selamectin, milbemycin oxime | Increased risk of neurologic toxicity; avoid concurrent use |
| Other isoxazolines | Afoxolaner (NexGard), fluralaner (Bravecto), sarolaner (Simparica) | Duplicate therapy; do not combine |
| P-glycoprotein inhibitors | Ketoconazole, itraconazole, cyclosporine | May increase moxidectin blood levels; monitor closely |
| Other anthelmintics | Fenbendazole, albendazole, levamisole | Generally safe but unnecessary duplication; consult vet |
| Corticosteroids | Prednisone, dexamethasone | No direct interaction, but may mask side effects |
Always inform your veterinarian of all medications, supplements, and over-the-counter products your dog is receiving before starting Credelio Quattro.
Monitoring Requirements and Follow-Up
Recommended Monitoring Protocol
- Before starting: Heartworm antigen test (required). Fecal flotation to assess existing intestinal parasite burden.
- First month: Monitor for adverse reactions, especially gastrointestinal upset or neurologic signs.
- Every 6-12 months: Annual heartworm test even while on preventive (no preventive is 100% effective). Fecal exam to confirm parasite control.
- Ongoing: Report any vomiting, diarrhea, or behavioral changes to your veterinarian.
Heartworm Testing Compliance
The American Heartworm Society recommends annual heartworm testing regardless of preventive compliance. Missed doses, vomiting after administration, or drug interactions can compromise protection.
Cost Range and Availability
Pricing (2026 Estimates)
- 6-month supply: $85 - $120 depending on dog weight class
- 12-month supply: $160 - $230 depending on dog weight class
- Per-dose cost: Approximately $14 - $19 per monthly tablet
Generic Availability
As of 2026, no generic equivalent of Credelio Quattro is available. The product is still under patent protection. Generic lotilaner (flea/tick only) may become available in future years, but the four-drug combination remains proprietary to Elanco.
Where to Purchase
Credelio Quattro is available through:
- Your veterinarian's office (often with automatic refill programs)
- Verified online veterinary pharmacies (requires prescription upload)
- Chewy, 1-800-PetMeds, and other licensed online retailers with valid prescription
Warning: Never purchase from unauthorized sellers or international websites without U.S. veterinary licensing. Counterfeit parasite preventives are a documented problem.
What to Do If You Miss a Dose or Overdose Occurs
Missed Dose Protocol
- If less than 30 days late: Administer the missed dose immediately, then resume monthly schedule from that new date.
- If more than 30 days late: Administer immediately and consult your veterinarian about heartworm testing. Gaps in heartworm prevention may require additional testing before resuming.
- Do NOT double dose: Never give two tablets to "catch up." This increases the risk of adverse reactions.
Overdose Response
If your dog accidentally consumes more than the prescribed dose:
- Remove any remaining medication from your dog's access
- Note the amount consumed and time of ingestion
- Contact your veterinarian or emergency clinic immediately
- Call ASPCA Animal Poison Control: (888) 426-4435 (24/7, consultation fee applies)
- Monitor for vomiting, tremors, seizures, or loss of coordination
- Do not induce vomiting unless instructed by a veterinary professional
Alternatives to Credelio Quattro
If Credelio Quattro is not suitable for your dog, discuss these alternatives with your veterinarian:
Comparable All-in-One Products
- Simparica Trio: Sarolaner + moxidectin + pyrantel (flea/tick + heartworm + intestinal parasites, but no tapeworm coverage)
- Interceptor Plus: Milbemycin oxime + praziquantel (heartworm + intestinal parasites + tapeworms, but no flea/tick coverage)
- Tri-Heart Plus: Ivermectin + pyrantel (heartworm + roundworms/hookworms, no flea/tick or tapeworm)
Separate Product Regimens
Some owners prefer separate products for flea/tick and heartworm/intestinal parasite control:
- Flea/tick options: NexGard, Bravecto, Simparica, or topical options like Frontline Plus
- Heartworm/intestinal options: Heartgard Plus, Sentinel, or Interceptor
Your veterinarian will help determine the best protocol based on your dog's health status, lifestyle, regional parasite risk, and your compliance preferences.
Frequently Asked Questions
How long does my dog need to be on Credelio Quattro?
Year-round administration is recommended in most U.S. regions. Heartworm transmission can occur in any month, and fleas can survive indoors year-round. Your veterinarian will advise if seasonal use is appropriate for your specific location.
Can I use Credelio Quattro for cats?
No. Credelio Quattro is formulated and approved only for dogs. Never administer dog medications to cats, as this can cause severe toxicity.
Does Credelio Quattro protect against all types of worms?
It covers roundworms, hookworms, whipworms, and several tapeworm species. It does NOT protect against all tapeworm species (e.g., Echinococcus multilocularis may require additional treatment in endemic areas).
Can I split the tablet for smaller dogs?
No. Credelio Quattro tablets are not designed to be split. Use the appropriate weight-class tablet for accurate dosing.
What if my dog vomits after taking Credelio Quattro?
If vomiting occurs within 1 hour of administration, contact your veterinarian. They may recommend redosing. If vomiting occurs after 1 hour, the medication has likely been absorbed.
Is Credelio Quattro safe for MDR1-sensitive breeds?
Moxidectin is generally considered safer than ivermectin in MDR1-mutation carriers, but caution is still advised. Discuss genetic testing results with your veterinarian before starting.
Do I still need heartworm testing if my dog is on Credelio Quattro?
Yes. The American Heartworm Society recommends annual testing regardless of preventive compliance. No preventive is 100% effective, and early detection is critical.
Final Considerations
Credelio Quattro offers comprehensive parasite protection in a convenient monthly chewable format. However, it requires veterinary oversight, proper dosing by weight, and awareness of potential side effects—particularly in dogs with neurologic history or MDR1 gene mutations.
Always consult your veterinarian before starting, stopping, or changing any medication regimen. Your vet will assess your dog's individual health status, regional parasite risks, and lifestyle to determine if Credelio Quattro is the right choice for your pet.
For emergency poisoning concerns, contact ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Both services operate 24/7 and consultation fees apply.
Beth Carrasco
All our authors care for dogs every day — read more of their work on the authors page.
