Moxidectin

What is this medication for?

• Heartworm prevention (6-/12-month injectable ProHeart; monthly topical Advantage Multi); extra-label generalized demodicosis (0.2–0.4 mg/kg by mouth once daily)
• Heartworm prevention + fleas + parasites via topical combo

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.

• Prevention-safe vs treatment-risk split: the monthly microgram doses are MDR1-safe across genotypes (Mealey) — the DAILY demodicosis doses re-open the ivermectin-sensitivity question; know which regime you're dispensing.

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

• Oral daily (demodex doses): vomiting, wobbliness/unsteadiness, low energy/tiredness, inappetence (Dose-limiting)
• Injection-site/procedure reactions (ProHeart) (Label-era safety history — why availability has fluctuated)

Worth a phone call to your veterinarian

• Any new symptom that worries you.

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

• Neurotoxicity (tremors, coma) (MDR1-mutant dogs at high doses (ivermectin-rule applies); low-body-fat patients more prone)

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

• has or has had: Hypersensitivity; HW-positive dogs (test before starting prevention — reactions to microfilariae + risk)
• has or has had: >2-month dosing gap → retest before resuming; MDR1 status at demodicosis doses; cachectic/neonatal animals

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Spinosad
  • Other avermectins
  • Imidacloprid (combo product)

Storage and handling

ProHeart: veterinary-administered injectable (restricted post-2004 recall history — label dynamics matter); topical: monthly applicator.

Good to know

• Prevention-safe vs treatment-risk split: the monthly microgram doses are MDR1-safe across genotypes (Mealey) — the DAILY demodicosis doses re-open the ivermectin-sensitivity question; know which regime you're dispensing.
• ProHeart's 6-month injection = the compliance solution for forgetful owners, with a regulatory-history asterisk (2004 recall, label changes).
• Advantage Multi pairing: moxidectin (HW + parasites) + imidacloprid (fleas) in one spot-on — the combination-product era of parasiticide dispensing.