HomeMy WebLinkAboutHeartworm Treatment for Dogs at OCASHeartworm Treatment for Dogs at OCAS
Standard Operating Guideline for Veterinary Health Care Team
In order to minimize the need to euthanize otherwise adoptable dogs at OCAS, we
provide heartworm treatment using melarsomide hydrochlorine (adulticide
treatment). Recognizing that there are several treatment protocols, we use a
protocol that combines elements of the protocols put forth by the American
Heartworm Association and the drug manufacturers of melarsomide (Merial and
Zoetis). This protocol represents an informed and appropriate approach, taking into
account practical considerations as well as medical safety of each dog. We would
note that the manufacturer distinguishes treatments based on the different
symptomatic classes of heartworm, and that our protocol meets or exceeds these
recommendations for each class. It is the discretion of the Veterinary Health Care
Manager to make changes to the treatment protocol for an individual animal when
these are deemed medically necessary by the attending veterinarian.
Only animals owned by OCAS are eligible for heartworm treatment. Owned animals
are not candidates. Final decision-making for whether a dog is a heartworm
treatment candidate will be that of the Veterinary Health Care Manager. All dogs
undergoing heartworm treatment are placed in our foster program and this
programs gives those fosters the first right to adopt. Anyone interested in fostering
a heartworm positive dog must speak with a Veterinary Health Care Technician
prior to fostering. The VHCT goes over what heartworms are, how they are
transmitted, how Orange County Animal Services treats heartworms, what the
foster’s responsibilities are and what Orange County Animal Services is responsible
for. The Veterinary Health Care Technician goes over any questions and provides
any additional information.
When the foster picks up the dog, the Veterinary Health Care Technician again goes
over the treatment and any medications that will be provided and given by the
foster. They also give the foster the heartworm brochure (provided by Merial)
which identifies the scheduled injection dates and other important information,
including a medical addendum.
1) Patient selection
When dogs are identified as heartworm positive on the antigen heartworm test, the
Veterinary Health Care Technician examines a blood sample under the microscope
to determine if the dog is microfilariae positive. Depending on the case, if the dog is
antigen positive but microfilariae negative, the Veterinary Health Care Manager may
request a second antigen test to confirm the test result. The dog’s behavior is
evaluated to ensure that he or she has a temperament that makes him or her
available for adoption or placement. The Veterinary Health Care Manager then
determines whether the dog meets the criteria for treatment. If the dog is deemed
highly adoptable, the dog is flagged to have an exam performed by a veterinarian.
The veterinarian performs a physical exam and notes any symptoms of heartworm
disease and/or any comorbidities. The veterinarian will consult with the Veterinary
Health Care Manager (or the Assistant Director or Director in his or her absence),
who may order additional tests such as radiographs or laboratory work if needed.
Dogs with no or mild clinical symptoms of heartworm disease may be scheduled for
spay/neuter surgery as long as they are cleared by the veterinarian and approved
by the Veterinary Health Care Manager.
Patients are be grouped by symptoms into one of the following groups:
Mild symptoms or Class 1:
Asymptomatic or mild cough
Moderate symptoms of Class 2:
Cough, exercise intolerance, abnormal lung sounds
Severe symptoms or Class 3:
Cough, exercise intolerance, dyspnea, abnormal heart and lung
sounds, syncopy, ascites, hepatomegaly
Very severe symptoms or Class 4:
Caval syndrome: sudden onset of severe lethargy and weakness
accompanied by hemoglobinemia and hemoglobinuria
Generally, only dogs that fall into Class 1 and 2 would be treated for heartworms at
OCAS.
2) Treatment – pre-adulticide
After the patient is identified as heartworm positive and passed the behavioral and
medical evaluations, the Veterinary Health Care Technicians administer a dose of
heartworm preventative and, if the patient also is microfilariae positive, they also
administer a glucocorticosteroid to reduce risk of anaphylaxis (Dexamethasone at
1mg per 25lbs). Heartworm prevention is continued every 30 days ongoing.
Exercise restriction is initiated. The Veterinary Health Care Technicians begin the
patient on a 28 day course of Doxycycline at 10mg/kg BID. There is a rest period of
up to 4 weeks after the Doxycycline therapy. During this time the exercise
restriction is continued.
3) Treatment – adulticide
Patients that are identified as Class 1 (mild symptoms) are treated using a 2
injection protocol of melarsomide: Melarsomide injection #1 and #2 are
administered 24 hours apart at 2.5mg/kg deep IM in the middle of the lumbar
musculature in the 3rd through 5th lumbar region on alternating sides by a
veterinarian. The Veterinary Health Care Technicians pre-medicate patients using a
pain medication and sedative and administer a NSAID pain medication on each day
of the injection and for at least 3 days afterwards. If post-injection treatment with
Prednisone is indicated, it will be initiated by the veterinarian. The patient needs to
be strictly exercise restricted for at least another 30 days before regular exercise
can resume gradually.
Patients that are identified as Class 2 (moderate symptoms) as well as very small
breeds or dogs that are more than 9 years of age are treated using a 3 injection
protocol of melarsomide: Melarsomide injection #1 is administered at 2.5mg/kg
deep IM in the middle of the lumbar musculature in the 3rd through 5th lumbar
region by a veterinarian. Veterinary Health Care Technicians pre-medicate patients
using a pain medication and sedative and administer a NSAID pain medication on
the day of the injection and for at least 3 days afterwards. If post-injection
treatment with Prednisone is indicated, it will be initiated by the veterinarian.
Thirty days later, Melarsomide injection #2 and #3 are administered 24 hours apart
at 2.5mg/kg deep IM in the middle of the lumbar musculature in the 3rd through 5th
lumbar region on alternating sides by a Veterinarian. Veterinary Health Care
Technicians pre-medicate patients using a pain medication and sedative and
administer a NSAID pain medication on each day of the injection and for at least 3
days afterwards. If post-injection treatment with Prednisone is indicated, it will be
initiated by the veterinarian. The patient needs to be strictly exercise restricted for
at least another 30 days before regular exercise can resume gradually.
Heartworm preventative is given every 30 days on an ongoing basis. The patient is
scheduled for an antigen heartworm test 6 months post adulticide treatment.
4) Adoption
Adoption of the patient can take place once all Melarsomide injections are complete.
At the time of adoption, a Veterinary Health Care Technician goes over what has
been done, any medications given, and instructions for moving forward. This
includes heartworm prevention schedule, exercise restriction, and a heartworm
testing protocol. Once adoption is complete, OCAS will provide no additional
veterinary care for the adopted dog and the new owner will accept all medical and
financial responsibility for the pet.
Approved 9/26/17
Bob Marotto, Director
Heartworm Treatment for Dogs at OCAS
Standard Operating Guideline for Veterinary Health Care Team
I hereby acknowledge that I have read the above policy of Orange County’s Animal
Services Department and that I fully understand it.
I understand that adherence to this policy is a condition of my employment with
Orange County’s Animal Services Department.
Signature of Employee _____________________________________________________
Printed Name of Employee__________________________________________________
Date Signed______________________________________________________________