Small Animal Clinical Pharmacology - CYF MEDICAL DISTRIBUTION

CHAPTER 12 IMMUNOMODULATORY THERAPY
Immunoregulin
Clinical applications
Immunoregulin has been used in a range of clinical situations,
including:
● FeLV or feline viral rhinotracheitis infection
● canine staphylococcal pyoderma
● canine oral melanoma, mast cell tumor.
Mechanism of action
Immunoregulin is a killed suspension of the bacterium
Propionibacterium acnes, which is reported to have a
range of immunostimulatory effects, including enhancement
of antibody production, cell-mediated immunity,
macrophage and NK cell function.
Formulations and dose rates
A range of dosage regimens is reported.
CATS
• Immunoregulin has been given at 0.25 (for a 2.5 kg cat)
–0.5 mL (for a 5 kg cat) IV twice weekly for 2 weeks, then once
weekly for 3 weeks and fi nally once monthly for 2 months
DOGS
• For dogs with staphylococcal pyoderma the drug is
administered as an adjunct to standard therapy in chronic
cases of the disease. The recommended dose rates depend
upon bodyweight (0.25 mL for a dog under 7 kg, 0.5 mL for a
dog 7–20 kg, 1.0 mL for a dog 21–34 kg, 2.0 mL for a dog over
34 kg) and the drug is given by IV injection twice weekly during
weeks 1 and 2 of therapy, then by weekly injection during
weeks 3–12. A response should be observed within 12 weeks,
but some dogs may require a monthly injection to maintain
remission
Adverse effects
● Mild anaphylactoid reactions characterized by
vomiting, anorexia, pyrexia and lethargy.
● There may be localized inflammation if there is
extravasation of the agent during injection.
Ivermectin
Clinical applications
Ivermectin is a broad-spectrum parasiticide that is
widely used in veterinary medicine. The drug is currently
unlicensed for use in the dog, with the exception
of a specific formulation (Heartgard®) used as a heartworm
preventive in many countries. A range of ectoparasitic
infections of the dog have been treated using
the 1% w/v bovine preparation (Ivomec®, Merial). The
antiparasitic effects of ivermectin are discussed in
Chapter 10.
Mechanism of action
On the basis of studies in other species, it has sometimes
been proposed that ivermectin has an immunomodulatory,
as well as antiparasitic, effect. In one reported
study, administration of Ivomec® to healthy laboratory
beagles had no effect on blood lymphocyte counts,
CD4 : CD8 T-cell ratios or lymphocyte blastogenic
responses in vitro. The authors suggest that ivermectin
may act in a similar fashion to levamisole, being able to
restore subnormal immune function, but not enhance
immunity to supranormal levels (see below).
Formulations and dose rates
• A range of ectoparasitic infections of the dog has been treated
using the 1% w/v bovine preparation (Ivomec®, Merial) given
by subcutaneous injection at a dose of 0.2–0.3 mg/kg.
Regimens of two such injections 2 weeks apart, or weekly
injections for a 2-month period, have been described
• Ivomec® has also been administered orally over longer periods
at 0.6 mg/kg q.24 h
Contraindications and precautions
At doses above those approved for heartworm prophylaxis,
ivermectin must be used cautiously in collies, shelties
or related breeds. Care must also be taken when
using in dogs with circulating microfilaria of Dirofilaria
immitis.
Levamisole
Clinical applications
Levamisole is an anthelmintic agent used principally for
the treatment and control of a range of nematodes in
domestic species and as a microfilaricide in dogs. In the
context of this chapter, levamisole has often been advocated
as an adjunctive immunostimulant drug in small
animal medicine, with particular application to canine
microbial disease with underlying immunodeficiency.
The basis for this usage might lie in the fact that this
agent has immunomodulatory properties and is sometimes
used as a vaccine adjuvant in domestic livestock.
Fundamentally, however, the immunomodulatory properties
of levamisole in companion animals remain
unproven, and use of this agent is associated with a
range of potentially severe side effects. It is difficult to
recommend its use given these circumstances.
The specific clinical applications to which levamisole
have been applied include:
● chronic, recurrent cutaneous infection, particularly
canine deep pyoderma
● aspergillosis or penicillosis
● immunodeficiency of Weimaraner dogs
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