From Flea Pills to Heartworm Preventatives: Top 5 Dog Meds on Chewy in 2025

Choosing the right parasite preventative for your dog can be overwhelming, especially with so many products on the market claiming to offer the best protection. In 2025, Chewy remains a trusted destination for pet parents seeking reliable, vet-recommended medications to defend against fleas, ticks, heartworms, and intestinal worms. Whether you're looking for a fast-acting over-the-counter solution or an all-in-one prescription chewable, this guide compares the top five dog medications available on Chewy, highlighting their benefits, pricing, and coverage to help you make a smart, informed choice for your canine companion.

Parasites represent a significant health concern for dogs across the United States. These unwanted hitchhikers—including fleas, ticks, heartworms, and intestinal worms—can cause serious health complications ranging from uncomfortable irritation to life-threatening conditions. Fleas can trigger severe allergic reactions and anemia, while ticks transmit debilitating diseases such as Lyme disease, ehrlichiosis, and Rocky Mountain spotted fever. Perhaps most concerning is heartworm disease, which can cause permanent damage to the heart, lungs, and blood vessels, potentially proving fatal without proper treatment. Fortunately, veterinary pharmaceutical advancements have yielded highly effective preventative medications that protect against multiple parasites simultaneously. Modern preventatives typically come in palatable formulations that dogs accept readily, improving compliance and ensuring continuous protection.

Prescription vs. Over-the-Counter Options

The majority of comprehensive parasite preventatives require a veterinary prescription. This requirement exists because these medications contain powerful active ingredients that need appropriate dosing based on a dog's health status, weight, and medical history. Prescription medications generally offer broader spectrum protection and greater efficacy than their over-the-counter counterparts. Non-prescription alternatives, while more accessible for immediate needs, typically address only specific parasites (usually fleas) rather than providing the comprehensive protection many pet owners seek. Though convenient for addressing acute flea infestations, these products often lack the broader protection against ticks, heartworms, and intestinal parasites. From a financial perspective, prevention significantly outweighs treatment costs. Treating established heartworm disease can cost upwards of $1,000, while a year of preventative medication generally runs between $70-$250, depending on the product and dog size. Similarly, addressing severe flea infestations or tick-borne illnesses requires substantial veterinary intervention, making regular preventative use the more economical approach.

Released in 2020, Simparica Trio has quickly established itself as a leading comprehensive parasite preventative for dogs. This FDA-approved chewable medication delivers a powerful triple-action formula through its active ingredients: sarolaner, moxidectin, and pyrantel. Each monthly dose provides complete protection against fleas, ticks, heartworms, roundworms, and hookworms.

Comprehensive Parasite Protection

What distinguishes Simparica Trio from other preventatives is its exceptional range of coverage. The medication tackles five different tick species, including the black-legged tick (deer tick) responsible for transmitting Lyme disease. This specific protection against the Lyme disease vector makes Simparica Trio the only FDA-approved medication that effectively prevents this debilitating condition through targeted tick control.

Administration and Pricing

The savory chewable formulation makes administration straightforward for most dog owners. Priced at approximately $186.82 for a 6-month supply for dogs weighing between 11.1-22.0 pounds, Simparica Trio represents a mid-range investment for comprehensive protection. The pricing scales are based on weight ranges, with larger dogs requiring higher dosages at increased cost.

Limitations

Despite its comprehensive protection, Simparica Trio comes with certain restrictions. The medication is not suitable for puppies under 8 weeks of age or dogs weighing less than 2.8 pounds. Additionally, like all effective parasite preventatives, it requires a veterinary prescription, meaning owners must maintain regular veterinary relationships to access this medication.

As the newest entrant to the parasite prevention market, NexGard PLUS launched in 2024 to considerable attention from veterinarians and pet owners alike. This innovative chewable combines afoxolaner and milbemycin oxime to deliver comprehensive protection against external and internal parasites in one monthly dose.

Fresh Approach to Comprehensive Protection

NexGard PLUS builds upon the established reputation of the original NexGard product, which revolutionized flea and tick control with its palatable chewable format. The PLUS formulation adds internal parasite protection, creating a true all-in-one solution that addresses fleas, ticks, heartworms, roundworms, and hookworms.

Palatability and Pricing

The beef-flavored chewable format appeals to most dogs, eliminating the struggle many owners face when administering traditional medications. This ease of administration supports consistent monthly dosing, critical for maintaining uninterrupted protection. At approximately $230.99 for a 6-month supply for large dogs (66.1-132 lbs), NexGard PLUS represents a premium price point among preventative options.

Veterinary Endorsement

NexGard PLUS has quickly gained veterinary recommendation due to its comprehensive protection and the established track record of its parent product. The FDA approval provides additional confidence in its safety and efficacy profile. As with other comprehensive preventatives, NexGard PLUS requires a veterinary prescription, ensuring appropriate dosing based on the individual dog's needs.

With the longest market presence among top preventatives, Heartgard Plus has protected dogs since 1993. This venerable medication has built an unparalleled reputation with over two billion doses administered worldwide, making it the most established name in heartworm prevention.

Focused Protection at Budget-Friendly Pricing

Heartgard Plus combines ivermectin for heartworm prevention with pyrantel to address intestinal parasites like roundworms and hookworms. Its focused approach delivers essential protection without the higher price tag of broader-spectrum products. At approximately $71.39 for a 6-month supply for medium dogs (26-50 lbs), Heartgard Plus represents the most economical option among prescription preventatives.

Palatability and Administration

The real-beef chewable formulation makes monthly administration simple, with most dogs accepting the medication as a treat. This palatability ensures consistent protection without the struggle often associated with pill administration.

Complementary Protection Needed

The primary limitation of Heartgard Plus is its focused protection—while excellent for heartworms and intestinal parasites, it provides no defense against fleas and ticks. Dog owners choosing Heartgard Plus must typically pair it with a separate flea and tick preventative, potentially increasing total parasite protection costs. However, this approach allows for customized protection based on geographic risks and seasonal parasite pressures.

Introduced in 2014, Bravecto Chews revolutionized the flea and tick preventative market with its extended protection period. Unlike monthly products, Bravecto provides 12 weeks of continuous protection against fleas and ticks, requiring only 4-5 doses annually instead of the typical 12 monthly treatments.

Revolutionary Extended Protection

The active ingredient fluralaner delivers persistent protection against multiple tick species and fleas for a full three months per dose. This extended efficacy dramatically reduces the chances of missed doses, as owners need to remember treatment only quarterly rather than monthly.

Cost Considerations

While the upfront cost appears substantial at $207.97 for a 3-month supply for dogs weighing 44-88 pounds, the annual cost becomes comparable to monthly products when calculated over the full year. For owners who struggle with medication schedules, the convenience of quarterly dosing often justifies any price premium.

Complementary Protection Required

Similar to Heartgard Plus, Bravecto focuses exclusively on external parasites (fleas and ticks) without addressing heartworm disease or intestinal parasites. Dog owners selecting Bravecto must pair it with a heartworm preventative like Heartgard Plus for complete protection, creating an effective but potentially more complex prevention protocol.

For immediate flea control without a veterinary visit, Advantus Soft Chews offer an accessible over-the-counter solution. These chews contain imidacloprid, which starts eliminating adult fleas within one hour of administration, significantly faster than many prescription alternatives.

Accessibility and Speed

The primary advantages of Advantus are its non-prescription status and rapid action. Available for immediate purchase at approximately $12.25 for 7 doses (for dogs 23-110 lbs), these soft chews provide quick relief during active flea infestations without waiting for a veterinary appointment.

Flexible Administration

Advantus can be given daily as needed, making it suitable for addressing acute flea problems or supplementing regular preventative protocols during heavy infestation periods. The soft chew format appeals to most dogs, simplifying administration during these challenging times.

Limited Protection Scope

The significant limitation of Advantus is its narrow focus on adult fleas only, without addressing ticks, heartworms, or intestinal parasites. Additionally, it lacks the persistent protection of monthly preventatives, requiring daily administration during active infestations. These factors make Advantus more suitable for temporary relief rather than as a standalone preventative program.

When evaluating parasite preventatives, dog owners must balance several key factors: spectrum of protection, administration frequency, prescription requirements, and cost-effectiveness.

Annual Cost Comparison

The total annual investment varies significantly across products:

• Simparica Trio: Approximately $373.64 annually for complete protection (dog 11-22 lbs)
• NexGard PLUS: Approximately $461.98 annually for complete protection (dog 66-132 lbs)
• Heartgard Plus: Approximately $142.78 annually for heartworm and intestinal parasite protection (dog 26-50 lbs)
• Bravecto Chews: Approximately $277.29 annually for flea and tick protection (dog 44-88 lbs)
• Advantus: Variable cost depending on usage pattern, but approximately $638.75 if used daily (dog 23-110 lbs)

When considering Heartgard Plus, owners typically need to add a flea and tick preventative, bringing the total annual cost to $350 or more, depending on the products selected.

Coverage Spectrum

All-in-one solutions like Simparica Trio and NexGard PLUS offer the most comprehensive coverage against external and internal parasites. Specialized products like Heartgard Plus and Bravecto excel in their specific domains but require complementary products for complete protection. Advantus addresses only adult fleas, making it the most limited option for overall parasite management.

Administration Frequency

Monthly administration remains the standard for most preventatives, including Simparica Trio, NexGard PLUS, and Heartgard Plus. Bravecto's quarterly dosing schedule represents a significant convenience advantage for busy owners or those who struggle with consistent monthly administration. Advantus stands apart with its as-needed dosing protocol, requiring daily administration during active infestations.

Prescription Requirements and Accessibility

Four of the five top medications—Simparica Trio, NexGard PLUS, Heartgard Plus, and Bravecto—require veterinary prescriptions, necessitating regular veterinary relationships. This requirement ensures appropriate dosing and monitoring, but may present access challenges for some pet owners. Advantus, as an over-the-counter option, offers immediate accessibility without veterinary involvement, making it valuable for addressing sudden flea problems.

Your dog’s health and comfort depend on effective, consistent parasite protection. Whether you opt for a comprehensive solution like Simparica Trio or NexGard PLUS, or prefer a budget-friendly, focused approach with Heartgard Plus or Bravecto, the key is matching the product to your dog's unique needs and your lifestyle. And for unexpected flea flare-ups, Advantus offers quick, convenient relief. Consult your vet, weigh your options carefully, and rest assured that with the right preventative, you're giving your pup the best defense against parasites in 2025 and beyond.