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When to Use Trifexis vs Sentinel for Dogs

Which Preventative Is Right for Your Pet?

By Lauren Leonardi . September 24, 2013 | See Comments

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When to Use Trifexis vs Sentinel for Dogs

Fleas and ticks and their other pest friends are not only gross, but annoying to both pets and pet parents. Find out more here about two preventative medications that stop these horrible little creatures in their tracks.

What are the differences that emerge when comparing Trifexis vs Sentinel for dogs? These popular preventatives are comparable in many ways, including price. Both medications are administered orally to keep parasitic worms, including heartworms, at bay. Both medications treat fleas -- one at the egg stage and one at the adult stage. And both medications are administered orally, in the form a flavored chewable tablet. So which one is better for your dog?

WHAT TYPES OF PESTS DO TRIFEXIS & SENTINEL PLUS PROTECT AGAINST?

Both drugs protect against heartworm, hookworm, roundworm, and whipworm.

  • Sentinel interrupts the flea life cycle by ensuring that female fleas who feed on treated animals will produce eggs that cannot hatch.
  • Trifexis also addresses fleas, by killing adult fleas.
  • Neither drug protects against ticks.
  • Both drugs are a good alternative to monthly spot-on topical treatments for dogs who have sensitive skin, or in cases where spot-ons are not practical because children or other animals in the home may have contact with topicals while they’re still wet.

HOW LONG DOES A DOSE LAST?

Both medications are to be administered orally once a month, and will last for 30 days.

ARE THERE ANY SIDE EFFECTS OF TRIFEXIS OR SENTINEL?

  • The primary ingredients in Trifexis are spinosad and milbemycin, which both have very low rates of toxicity in mammals.
  • Sentinel also contains milbemycin. Its second ingredient is lufenuron, which is primarily non-toxic to dogs, though it can sometimes be irritating to the stomach.
  • These are, by and large, safe drugs, with one exception. Milbemycin should not be given to Collies or other herding dogs. These breeds have a known intolerance for this drug.

WHAT IS THE AGE MINIMUM FOR TRIFEXIS & SENTINEL?

Sentinel should not be given to puppies ‘till they’re at least 4 weeks of age, or 2 lbs. Trifexis should not be administered until puppies are 8 weeks of age, and 5 lbs.

CAN TRIFEXIS & SENTINEL BE ADMINISTERED TO PREGNANT PETS?

The effects of both drugs on pregnant and lactating dogs have not been evaluated.

HOW DO THEY WORK?

Lufenuron (in Sentinel) protects against both heartworms and fleas by attacking a naturally occurring glucose derivative found in the bodies of insects, called chitin. Neither dogs or humans require chitin to live, but fleas and certain intestinal worms need chitin to grow and live. Lufenuron attacks the chitin in these parasites, which -- in the case of fleas -- prevents them from ever developing an exoskeleton. In the case of worms, it attacks worms at the cellular level, preventing them from developing.

Spinosad (in Trifexis) kills adult pests through “hyperexcitation” of the nervous system. This is why dogs may appear itchy or restless in the first hour or so after taking the drug. Adult fleas may be especially active on their skin before falling dead from drug-induced nervous breakdowns!

 

Application

For the Prevention of...

Recommended age of application

Trifexis

Oral tablet, once a month.

Heartworm, hookworm, roundworm, whipworm, and adult fleas.

 

6 weeks or older

Sentinel

Oral tablet, once a month.

Heartworm, hookworm, roundworm, whipworm, and fleas at the larval stage.

4 weeks or older, 2 lbs or larger

More on Pest Control

The Top 10 Best Dog Collars
Using Flea and Tick Treatments Safely
How To Kill Fleas in the Yard

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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