What is milbemycin oxime + praziquantel?
Milbemycin oxime + praziquantel (brand name Interceptor Plus®) is a heartworm disease preventive that also controls hookworms, roundworms, whipworms, and tapeworms in dogs. This medication should take effect within one to two days.
How is milbemycin oxime + praziquantel given?
- Milbemycin oxime + praziquantel is given by mouth as a flavored chew tablet.
- It must be given with food to ensure adequate absorption.
What if I miss giving my dog a scheduled dose?
If you miss a dose, give it as soon as you remember, and then wait the recommended time for the next dose, as prescribed by your veterinarian. Do not give the pet two doses at once or give extra doses. If you are using milbemycin oxime + praziquantel as a heartworm preventive and more than 8 weeks have passed without giving it to your dog, contact your veterinarian for guidance.
Are there any potential side effects?
Milbemycin oxime + praziquantel may cause the following side effects:
- Vomiting
- Diarrhea
- Transient appetite loss
Serious adverse reactions may occur with higher doses. If any of the following signs develop, stop giving milbemycin oxime + praziquantel and contact your veterinarian immediately:
- Depression, lack of energy, or weakness
- Stumbling or collapse
- Seizures or coma
- Dilated pupils
- Excessive drooling
This medication should stop working in a few days, although effects can be longer in pets with liver or kidney disease.
Are there any risk factors for this medication?
DO NOT USE milbemycin oxime + praziquantel in:
- Dogs without a current negative heartworm test
- Puppies less than 6 weeks of age
- Puppies or dogs weighing less than 2 lb (900 g)
USE WITH CAUTION in:
- Pregnant or nursing animals (use has not been evaluated)
Some dog breeds are more sensitive than others to milbemycin oxime + praziquantel. (e.g., collies, sheepdogs, and collie or sheepdog-cross breeds). This sensitivity is typically due to a genetic mutation (ABCB1, previously known as MDR1) that makes them less able to tolerate high doses of certain medications. Appropriate doses are safe for these breeds. Your veterinarian will advise you on the safety of milbemycin oxime + praziquantel use in your dog.
Are there any drug interactions I should be aware of?
Several drugs can interact with milbemycin oxime + praziquantel, including:
- Albendazole
- Azole antifungals
- Cimetidine,
- Cyclosporine (Atopica®)
- Dexamethasone
- Diltiazem
- Erythromycin
- Phenobarbital
Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.
Is any monitoring needed with this medication?
- Your pet must be tested for heartworm before receiving any product containing milbemycin oxime. A life-threatening reaction can occur if your pet has a high load of immature worms and is given milbemycin.
- For dogs with a potential milbemycin sensitivity, DNA screening may be done before receiving the medication to determine if a pet has the genetic mutation responsible for adverse reactions to milbemycin.
- Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
- At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.
How do I store this medication?
- Store milbemycin oxime + praziquantel products at room temperature.
- Store in a dry location, away from heat and direct sunlight.
- Do not store this medicine in the bathroom, near the kitchen sink, or in damp areas. Exposure to heat or moisture may reduce the drug’s effectiveness.
- Keep the container out of reach of children and pets. 
What should I do in case of an emergency?
If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are unavailable, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms.
