Lecture: Immunosuppressive TX Flashcards
Most immunosuppressive agents have a …….
lag phase before reaching full efficacy
immunosuppressive guidelines (carefully monitor…..)
- careful monitoring of CBC and platelet counts during therapy
- antibiotic therapy necessary in the first few months of therapy
If worsening of skin lesions with steroids, consider:_____
before increasing dose
- demodecosis
- dermatophytosis
- bacterial infection
- calcinosis cutis (dogs)
After relapse of autoimmune dz …..
resistance to previously used glucocorticoids may be observed
most animals require therapy for
life
DLE (discoid lupus erythematous) and PE usually managed with
- topical glucocorticoid
- topical tacrolimus
- tetracycline and niacinamide
PF usually requires a combo of
glucocorticoids and another immunosuppressive agent
PV and BP usually require
very high doses that are rarely tolerated
High dose steroids can kill a patient due to
GI ulceration
SLE usually requires combo of
- glucocorticoids and another immunosuppressive agent
*Gold salts are contraindicated due to potential for renal toxicity
Glucocorticoids
- used for management of autoimmune diseases due to anti-inflammatory properties
- inhibits macrophages chemotaxis
- Phospholipase A2
- Reduce compliment levels
- Decrease capillary permeability
- Inhibit PMN chemotaxis and phagocytosis
- Stabilize lysosomal membranes
Rules for steroid therapy
- oral steroids
- alternate days to minimize adrenal suppression
- prednisone
- prednisolone
- methylprednisolone
- use lowest effective dose
Induction of steroid therapy
- lasts 10-14 days
- once no new lesions, tapering is started
- maintenance dose achieved in 8-10 weeks
Prednisone
immunosuppressive doses
- Dogs
- induction: 2.2-3.3 mg/kg q 12hr
- maintenance: 0.5-1 mg/kg q 48hr
- Cats
- induction: 3.3-4.4 mg/kg q 12hr
- maintenance: 1-2 mg/kg q 48hr
Immunosuppressive doses
Methylprednisolone
- Dogs
- Induction: 0.8-1.5 mg/kg q 12hrs
- Maintenance: 0.3-0.8 mg/kg q 48hrs
- Cats
- Induction: 1.5-3 mg/kg q 12hrs
- Maintenance: 0.6-1.5 mg/kg q 48hrs
*Less PUPD
Immunosuppressive doses
dexamethasone
- Dogs
- Induction: 0.1-0.2 mg/kg q 12hrs
- maintenance: 0.05-0.1 mg/kg q 48-72hrs
- Cats
- Induction: 0.2-0.4 mg/kg q 12hrs
- Maintenance: 0.1-0.2 mg/kg q 48-72hrs
Side effects of steroid therapy
- GI ulcers
- PU/PD
- Polyphagia
- Panting
- Behavioral changes
- Diabetes
- Steroid hepatopathy
Other side effect of steroid therapy
- Muscle weakness
- Osteoporosis
- Redistribution of body fat
- Decreased synthesis of thyroid hormones
- Inc risk of infections
- skin
- urinary tract
Side effects on skin of steroid therapy
- thin skin
- comedones
- demodicosis
- calcinosis cutis (dogs)
- skin fragility (cats)
Azathioprine metabolism
- TPMT deficiency leads to inc production of active metabolites => inc toxicity
- Some dogs have genetic deficiency in TPMT
Side effects of Azathioprine
- bone marrow suppression
- anemia
- leukopenia
- Thrombocytopenia
- pancreatitis
- Hepatitis
- Vomiting
- Hemorrhagic diarrhea
Azathioprine
- 2.2 mg/kg q 48hrs (50 mg tab)
- Lag phase of 4-6 weeks
- Dose should be reduced when used with xanthine oxidase inhibitor
- monitor CBC and platelet counts q 2 weeks
- DO NOT USE IN CATS
Chlorambucil
- used for cats
- Cytotoxic
- alkylating agent: causes DNA breaks and cross-links
- Toxic for B cells
- Lag phase
- Liver metabolism
- bone marrow suppression
- V/D
Chlorambucil
Dose
- 0.1-0.2 mg/kg q 48hrs (2 mg tab)
- Lag phase: 6 weeks
- monitor CBC and platelet counts q 2 weeks
- Safe for cats
