Ivermectin Dose Rates in Dogs

1. Heartworm Prevention (Prophylaxis)

• Dose: 6-12 mcg/kg (0.006-0.012 mg/kg) orally, once monthly
• This is the standard approved dose used in commercial products like Heartgard®
• FDA-approved oral doses go up to 0.024 mg/kg (24 mcg/kg)
• Products at this dose range are safe even for MDR1-mutant breeds

2. Microfilariae Clearance

• Dose: 50 mcg/kg orally, single dose
• Used after adulticide therapy to eliminate circulating microfilariae

3. Sarcoptic Mange (Sarcoptes scabiei)

• Dose: 200-400 mcg/kg SC or orally
• Frequency: Repeat every 2 weeks for 2-4 treatments

4. Demodectic Mange (Demodex canis) - Off-label

• Dose: 300-600 mcg/kg orally, once daily
• Duration: Continue until 1 month after two consecutive negative skin scrapings (typically 3-6 months)
• Important: Start low (1/3 dose for 3 days, then 2/3 dose for 3 days) and escalate gradually to check for breed sensitivity

5. Ear Mites (Otodectes cynotis)

• Dose: 200-400 mcg/kg SC or orally
• Frequency: 2 treatments, 2 weeks apart

6. Intestinal Parasites (off-label)

• Dose: ~200 mcg/kg (0.2 mg/kg) orally, single dose

MDR1/ABCB1 Gene Mutation - Critical Warning

• Dogs homozygous for MDR1 will develop toxicosis at demodicosis treatment doses
• Dogs heterozygous react less severely but are still at risk
• The MSD Veterinary Manual notes that critical signs appear at 120-150 mcg/kg in sensitive dogs

Summary Table

Note: Always confirm the MDR1 gene status before using higher doses. Genetic testing is available. Do not use ivermectin in puppies under 6 weeks of age.