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Efficacy of ProHeart® 6 (moxidectin)

Compliance is Key

ProHeart® 6 (moxidectin) had 100 percent efficacy in two clinical effectiveness trials supporting FDA approval.2

Preapproval Challenge Study3


A single dose of ProHeart 6 dosed at 0.17 mg/kg ensured complete protection against heartworm infection.

See Study Design

  • 32 purpose-bred dogs, ≥8 months old.
  • Dogs were assigned to one of four treatment groups (n=8) on Day 0: ProHeart 6, 0.06 mg/kg; ProHeart 6, 0.17 mg/kg; ProHeart 6, 0.50 mg/kg; or placebo.
  • Each dog was inoculated SQ with 50 L3 heartworms on Day 180 and examined for heartworm between Days 330 and 331.

Preapproval Field Study2


None of the dogs enrolled in the study tested positive for heartworms.

See Study Design

  • 374 client-owned dogs of various breeds ranging from 6 months to 15 years of age.
  • Dogs received ProHeart 6 (n=280) at 0.17 mg/kg on Month 0 and Month 6 or tablets of an approved heartworm preventative medication (n=94) every 30 days for 365 days.
  • Antigen and microfilaria testing was performed prior to enrollment and at Months 3, 6 and 12.

Six Months of Efficacy

A unique mode of action (MOA) delivers sustained concentrations, providing six months of efficacy:

  • Slow-dissolving microspheres contain moxidectin and prolong its effects.
  • Moxidectin redistributes from plasma to adipose tissue.
  • Adipose tissue acts as a reservoir, allowing six months’ protection against heartworm disease.
IMPORTANT SAFETY INFORMATION: PROHEART 6 should be used in healthy dogs. Do not administer to sick, debilitated, underweight dogs or dogs that have a history of weight loss. Prior to administration, PROHEART 6 certified veterinarians should continue to assess patient health through a medical history, physical examination and if deemed appropriate, diagnostic testing. Continue to use caution when administering PROHEART 6 concurrently with vaccinations. Adverse events, including anaphylaxis, have been reported following the concomitant use of PROHEART 6 and vaccines. In some cases, anaphylactic reactions have resulted in death. Use with caution in dogs with pre-existing or uncontrolled allergic disease (food allergy, atopy or flea allergy dermatitis). Dogs receiving PROHEART 6 should be tested for existing heartworms as per the product label. In people, avoid PROHEART 6 contact with eyes. If contact with the eyes occurs, rinse thoroughly with water for 15 minutes and seek medical attention immediately. PROHEART 6 is available only to veterinarians through a restricted distribution program. Only certified veterinarians and staff can administer it. To obtain additional information including a copy of the product labeling, click here or call 1-888-ZOETIS1 (963-8471).
  1. Data on file. ProHeart 6 Freedom of Information Summary, NADA 141-189.
  2. Lok JB, Knight DH, Wang GT, et al. Activity of an injectable, sustained-release formulation of moxidectin administered prophylactically to mixed-breed dogs to prevent infection with Dirofilaria immitis. Am J Vet Res. 2001;62(11):1721-1726.



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