How safe is NexGard for dogs?

NexGard is a brand of flea and tick preventives that contains the ingredient isoxazoline. Isoxazoline-containing preventives can cause toxicity if given incorrectly or if an overdose occurs. These preventions are generally safe to use if the appropriate dose is administered. Dogs can become exposed to toxic quantities through the ingestion or absorption of household insect sprays, foggers, and granules. Causes of Flea and Tick Medicine Poisoning in Dogs often become poisoned unintentionally either through the misuse of flea and tick prevention or through the accidental ingestion or absorption of insecticides. Prior to medicating your dog, verify the correct drug, dose and size of the product and that the proper time frame in between doses has occurred nor that someone else in the family already gave it. Adverse reactions such as excessive drooling, paw flicking/scratching, and ear twitching are often mild and can go away on their own. Although drooling may recur for several days after use of a flea-control product, most mild to severe symptoms resolve within a few days.

Merial, the manufacturer of Nexgard/Nexgard Spectra have advised us that they have no concerns about these products when used in healthy animals according to the data sheet. As prescription medications these products have undergone extensive testing and are monitored by the Veterinary Medicines Directorate for Quality, Safety and Efficacy. Even at five times the recommended dose these products have been found to be safe. Over 50 million doses of NexGard have been sold since the launch of this product and continuous monitoring of the product safety is carried out worldwide. We would like to reassure you that it is very unusual for animals to show untoward effects following treatment with NexGard. Adverse effects are generally mild and occur very rarely (less than 1 animal in 10,000 treated). This statistic includes mild adverse reactions and unsubstantiated/incidental ones. If we had any concerns you can be reassured that we would not be prescribing NexGard for our own or clients pets.

The FDA considers products in the isoxazoline class to be safe and effective for dogs and cats but is providing this information so that pet owners and veterinarians can take it into consideration when choosing flea and tick products for their pets. Isoxazoline products have been associated with neurologic adverse reactions, including muscle tremors, ataxia, and seizures in some dogs and cats. Although most dogs and cats haven’t had neurologic adverse reactions, seizures may occur in animals without a prior history. The FDA-approved drugs in this class are Bravecto (fluralaner) tablets for dogs Bravecto (fluralaner) topical solution for cats and dogs Bravecto Plus (fluralaner and moxidectin) topical solution for cats Bravecto 1-month (fluralaner) tablets for dogs Credelio (lotilaner) tablets for dogs and cats Nexgard (afoxolaner) tablets for dogs Nexgard Plus (afoxolaner, moxidectin, and pyrantel) chewable tablets for dogs. Although these products can and have been safely used in the majority of dogs and cats, pet owners should consult with their veterinarian to review their patients’ medical histories and determine whether a product in the isoxazoline class is appropriate for their pet. If your dog or cat experiences any adverse event while using an isoxazoline product, first consult your veterinarian. The FDA continues to monitor adverse drug event reports for these products and encourages pet owners and veterinarians to report adverse drug events.