1

Split dose (3 injections), melarsomine and doxycycline; thoracic radiography, CBC, UA, chemistry panel, coagulation profile

↑ efficacy, ↓ risk of PTE, safety of phased heartworm kill, no resistance concern

Cost $$$$; exercise restriction for 2 months

Appropriate for all; best approach for severe heartworm disease

2

Standard dose (2 injections), melarsomine and doxycycline; thoracic radiography, CBC, UA, chemistry panel, coagulation profile

↓ cost, ↓ risk of PTE (vs standard dose), exercise restriction only 1 month, no resistance concern

Cost $$$; ↑ risk of PTE (vs split dose); ↓ kill efficacy (vs split dose)

Appropriate when financial constraints and mild to moderate heartworm disease

3

Standard dose (2 injections), melarsomine

↓ cost; exercise restriction only 1 mo, no resistance concern, easier for shelters

Cost $$; ↑ risk of PTE (vs standard dose); ↓ kill efficacy (vs split dose); cage rest imperative

Appropriate when financial constraints and mild heartworm disease

4

Nonarsenical adulticide treatment: ivermectin, milbemycin, selamectin, or moxidectin with doxycycline

↓ cost, no injections, no hospitalization, shorter treatment duration than slow kill protocol

Cost $; ↑ risk of resistance, not approved by AHS, ~12-month course, lung disease progression, time of heartworm death unknown

Appropriate when there are severe financial or other constraints, lack of melarsomine availability, or failure of melarsomine treatment to clear dog previously

5

Slow kill nonarsenical adulticide treatment with ivermectin, milbemycin, selamectin, or moxidectin at preventive dosage

Inexpensive; no injections

↑ risk of resistance, 30-month course, lung disease progression, time of heartworm death unknown

Should be avoided; MUST clear microfilariae