what is the current AHS-recommended heartworm treatment protocol for dogs with class III disease?

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The American Heartworm Society (AHS) three-dose melarsomine dihydrochloride protocol combined with doxycycline and a macrocyclic lactone is the recommended treatment for class III canine heartworm disease. The protocol applies to classes 1 through 3 disease without caval syndrome, and all dogs treated with this regimen in one multicenter cohort survived treatment and became antigen-negative on long-term follow-up. 1 Pretreatment stabilization precedes adulticide therapy in class III dogs. Class III disease carries greater cardiopulmonary compromise, and inflammatory and hemostatic markers — including D-dimer, C-reactive protein, interleukin-6, and cardiac troponin I — are elevated above the reference range at diagnosis in class III dogs and remain at pathological levels longer than in class I or II dogs during treatment. 8 Monitoring these markers during treatment is beneficial for predicting clinical outcomes and complications associated with melarsomine. 8 Doxycycline is administered at 10 mg/kg PO q12h for 28 days to reduce Wolbachia burden prior to adulticide therapy. 27 At this dose, all dogs achieve Wolbachia DNA negativity by 28 days post-treatment. 2 Gastrointestinal side effects are more frequent at 10 mg/kg BID than at lower doses, though the 10 mg/kg BID regimen provides the most complete Wolbachia elimination. 2 Melarsomine dihydrochloride is administered as three injections at 2.5 mg/kg IM using the split-dose protocol: a single injection on day 1, followed by two injections given 24 hours apart beginning 30 days later. 27 Sedation to facilitate injection and application of ice at the injection site are used in a subset of patients to improve tolerability. 1 After each adulticide injection, hospitalization with cage rest is standard; median hospitalization time is 12 hours (range 6–48 hours). 1 A macrocyclic lactone preventive is administered concurrently throughout the treatment period to eliminate susceptible larvae and prevent new infections. 37 The