Comparing Nexgard and Sentinel: Which is Better for Your Dog?
Choosing between Nexgard and Sentinel can be challenging for dog owners wanting the best protection against parasites. Understanding the differences in coverage, ingredients, and purpose is key to making the right choice for your pet’s health.
What Does Sentinel Do?
Sentinel Flavor Tabs are monthly, veterinarian-prescribed chewables containing milbemycin oxime and lufenuron. These ingredients work together to provide broad-spectrum protection:
- Milbemycin oxime prevents heartworm disease by eliminating larvae stages of heartworms (Dirofilaria immitis).
- Controls adult hookworms, roundworms, and whipworms.
- Lufenuron acts as a flea growth inhibitor—preventing flea eggs from hatching but does not kill adult fleas.
Sentinel is safe for puppies as young as 4 weeks and over 2 lbs. It offers one of the most comprehensive internal parasite protections on the market.
What Does Nexgard Do?
Nexgard is not detailed in the supplied material, but it is known to be a monthly oral chew containing afoxolaner, which kills adult fleas and ticks. It does not prevent heartworm disease or control intestinal parasites, meaning it often needs to be combined with another medication for comprehensive coverage.
Which Is Better?
The answer depends on your dog’s needs:
- If you’re looking for **broad internal parasite control** including **heartworms, roundworms, hookworms, whipworms**, and **flea eggs**, Sentinel is more comprehensive.
- If you are primarily concerned with **adult fleas and ticks**, Nexgard provides faster results in killing them but lacks internal parasite protection.
In many cases, a combination of both products—or switching to a product that offers both tick and internal parasite control—might be recommended.
Safety and Administration
Sentinel tablets are flavored with beef or pork liver, and administration is simple—given orally once per month with food. It’s generally well-tolerated, but side effects may include:
- Vomiting
- Lethargy
- Urticaria (hives)
- Anorexia
- Ataxia (loss of coordination)
Ensure your pet is tested for heartworms prior to giving Sentinel, especially if this is their first dose.
Key Advantages of Sentinel
- Prevents heartworm disease
- Controls major intestinal parasites
- Inhibits flea egg development (essential to prevent infestations)
- Safe for breeding, pregnant, and nursing dogs
- Convenient once-a-month dosing
Important Considerations
- Storage: Keep Sentinel in a dry area at room temperature (59–77°F).
- Veterinary oversight: Sentinel is prescription-only and should only be used under vet guidance.
- Drug interactions: Inform your vet about all medications your dog is on, especially cyclosporine, azoles, erythromycin, and amiodarone.
Conclusion
If your goal is to provide comprehensive parasite prevention including internal worms and future flea infestations, Sentinel is the better standalone option. For tick and adult flea protection, Nexgard might be more effective short-term, but may require pairing with another medication to cover all health bases. Consult your veterinarian to choose the best regimen tailored to your pet’s age, weight, and environment.





