Milbemycin Oxime

What is this medication for?

• Heartworm prevention, hookworm/roundworm/whipworm control (FDA-approved); demodicosis, scabies, cheyletiellosis (higher doses)
• Heartworm prevention, adult hookworm/roundworm control

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Generally well tolerated at labeled dose

Worth a phone call to your veterinarian

• CNS toxicity (wobbliness/unsteadiness, depression, tremors, mydriasis) at high doses (Dose-dependent, esp. ABCB1-mutant breeds (1–2.2 mg/kg range))
• Vomiting, diarrhea (Demodex-dose treatment) (Uncommon)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Manufacturer: not for puppies <4 weeks/<2 lbs or kittens <6 weeks/<1.5 lbs
• has or has had: Test for pre-existing heartworm infection before starting — dogs with high microfilaria burden can develop a transient shock-like syndrome; genetic ABCB1 testing recommended before high-dose therapy in susceptible breeds

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • P-glycoprotein inhibitors (azole antifungals, cyclosporine, diltiazem, erythromycin/clarithromycin, quinidine, spironolactone, amiodarone, tamoxifen, verapamil, carvedilol)
  • Benzodiazepines

Storage and handling

Room temperature, tightly sealed container.

Good to know

• Considered a safer alternative to ivermectin in ABCB1-mutant breeds when used at labeled heartworm-prevention doses, but genetic testing is still prudent before high-dose (demodicosis) therapy.
• Demodicosis treatment is a significant financial commitment given the extended treatment duration at above-label doses — set owner expectations on cost and duration upfront.
• Sentinel combination product also provides flea egg development inhibition via lufenuron — worth clarifying with clients which product (Interceptor vs. Sentinel) they actually have.