Guide to Choosing Heartworm Therapeutic Protocol
Guide to Choosing Heartworm Therapeutic Protocol
Protocol | Advantages | Disadvantages | Utilitya | |
|---|---|---|---|---|
1 | Split dose (3 injections), melarsomine and doxycycline; thoracic radiographs, CBC, UA, chemistry panel, coagulation profile | ↑ efficacy, ↓ risk of PTE, safety of phased worm kill, no resistance concern | Cost $$$$; exercise restriction for 2 months | Appropriate for all; best approach for severe HW disease |
2 | Standard dose (2 injections), melarsomine and doxycycline; thoracic radiographs, CBC, UA, chemistry panel, coagulation profile | ↓ cost, ↓ risk of PTE (vs standard dose), exercise restriction only 1 month, no resistance concern | Cost $$$; ↑ risk of PTE (vs split dose); ↓ kill efficacy (vs split dose) | Appropriate when financial constraints and mild to moderate HW 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 HW disease |
4 | Non-arsenical adulticidal therapy: oral ivermectin, topical moxidectin/imidacloprid, or oral moxidectin, at preventive dosage, 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 HW 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 non-arsenical adulticidal therapy with ivermectin, topical moxidectin/imidacloprid, or oral moxidectin, at preventive dosage | Inexpensive; no injections | ↑ risk of resistance, 30-month course, lung disease progression, time of HW death unknown | Should be avoided; MUST clear microfilariae |
a None of these is appropriate for initial management of caval syndrome but may be used to complete therapy after worm removal. UA = urinalysis; PTE = pulmonary thromboembolism; AHS = American Heartworm Society; $ = relative cost | ||||