The label says, word for word:
INTERCEPTOR PLUS is indicated for the prevention of heartworm disease caused by Dirofilaria immitis; and for the treatment and control of adult roundworm (Toxocara canis, Toxascaris leonina), adult hookworm (Ancylostoma caninum), adult whipworm (Trichuris vulpis), and adult tapeworm (Taenia pisiformis, Echinococcus multilocularis, Echinococcus granulosus, and Dipylidium caninum) infections in dogs and puppies two…
There are no known contraindications to the use of INTERCEPTOR PLUS.
Prior to administration of INTERCEPTOR PLUS, dogs should be tested for existing heartworm infections. At the discretion of the veterinarian, infected dogs should be treated to remove adult heartworms. INTERCEPTOR PLUS is not effective against adult D. immitis.
Mild, transient hypersensitivity reactions, such as labored breathing, vomiting, hypersalivation, and lethargy, have been noted in some dogs treated with milbemycin oxime carrying a high number of circulating microfilariae.
Do not use in puppies less than six weeks of age. Do not use in dogs or puppies less than two pounds of body weight.
The safety of INTERCEPTOR PLUS has not been evaluated in dogs used for breeding or in lactating females.
Not for use in humans. Keep this and all drugs out of the reach of children.
Every approved medicine has a field study behind it, and the label prints what happened:
The following adverse reactions have been reported in dogs after administration of milbemycin oxime or praziquantel: vomiting, diarrhea, depression/lethargy, ataxia, anorexia, convulsions, weakness, and salivation.
Approved by FDA under NADA 141-338. The FOI summary shows the NADA was originally approved June 16, 2012 under the trade name INTERCEPTOR SPECTRUM (sponsor Novartis Animal Health US, Inc.); a June 21, 2017 supplement 'provides for the addition of the treatment and control of adult tapeworm (Dipylidium caninum) infections in dogs and puppies two pounds of body weight or greater and six weeks of age and older.' The label gives no percentages for adverse reactions (the only percentages are from a palatability study). No Client Information Sheet.
The emergency page sorts the signs by how long you have, and the symptom checker asks what you are seeing. Reactions to a medicine can also be reported to the FDA yourself: how to report a problem.
These answers come from the approved label on DailyMed, read on 2 October 2026. Where the label does not say, the answer says so, and the vet or the pharmacist is the one to ask.
The approved use is quoted at the top of this page. It is a chewable given to dogs and puppies once a month to prevent heartworm disease and to treat and control adult roundworms, hookworms, whipworms and tapeworms.
The label gives no time. Ask the vet what to expect and by when.
It is given by mouth once every month. The label says the chewable can be offered by hand or added to a small amount of dog food, and that the dog should chew it instead of swallowing it whole. It may be broken into pieces for a dog that normally swallows treats whole. Make sure your dog eats the whole dose and watch for a few minutes afterwards, and if you think part of it was lost, the label recommends giving the dose again. For heartworm prevention the label says to start within one month of the dog's first seasonal exposure to mosquitoes and to continue until at least six months after the last one. It also says the chewable may be given all year round without a break. The label says dogs should be tested for heartworm infection before the first dose.
The label does not say what to do about a missed dose. Call the clinic or the pharmacy before you give the next one. What the label does say is that fewer than six monthly doses after the last exposure to mosquitoes may not give complete heartworm prevention.
The studies and the warnings are quoted above. The label has no line telling owners when to call the vet. The reactions it lists are vomiting, diarrhea, depression or low energy, unsteady walking, loss of appetite, convulsions, weakness and drooling. If you see any of them after a dose, call the vet.
Store it at room temperature, between 59° and 77°F. Keep it out of the reach of children.
The FDA says the best way to get rid of most unused or expired medicines is a take-back option: a drug take-back location, which can be at a pharmacy or a police station, or a prepaid mail-back envelope. If you cannot use one, the FDA says a medicine that is not on its flush list can go in the trash at home. Its steps are to mix the medicine with something unappealing such as dirt, cat litter or used coffee grounds, without crushing it, and to seal the mixture in a plastic bag before throwing it away. Flushing is only for medicines on that list, such as opioids. Do not give leftovers to another pet.
Write the dose, the times and the stop date here, then print this page for the fridge.
Dose and times: _____________________________________________
Stop date: _____________________________________________