Treatments for Allergy Block IV 2024 PDF

9/21/24 Treatments for Allergy Block IV 2024 Mitzi D. Clark, DVM, DipACVD [email protected] 1 Learning Objectives 1. Be abl...

9/21/24 Treatments for Allergy Block IV 2024 Mitzi D. Clark, DVM, DipACVD [email protected] 1 Learning Objectives 1. Be able to list the diagnostic steps needed in working up a pruritic dog or cat. 2. Be able to match the mechanism of action to its antipruritic drug. 3. Be able to list two side effects for each antipruritic drug/drug class discussed. 4. Given a clinical scenario (signalment, seasonality of itch, finances of client), be able to choose an antipruritic drug for that patient and justify your choice. 2 1  9/21/24 Cost of 32% skin conditions Veterinary Care 19% gastritis in 2023 11% ear infections 7.8% eye conditions 6% heart conditions Healthypaws® pet 5.5% growths and tumors insurance data 5.3% seizures Top 10 conditions in dogs 4.6% infections 4.6% UTIs 3.8% liver disease 3 Clinical Signs of Allergic Dermatitis Common Bilaterally symmetric, initially lesion-less pruritus Erythema Rare Angioedema Urticaria Anaphylaxis Varies by species 4 2  9/21/24 Distribution of Lesions 5 Treating Allergic Conditions Which allergic disease(s) is/are present? Life-long conditions require life- long therapy Multimodal approach Must treat secondary infections Must manage itch and inflammation Tailored to the individual 6 3  9/21/24 Clinical Approach to the Pruritic Pet 1) Rule Out Ectoparasites 2) Identify and Treat Secondary Infections 3) Break the Itch Cycle 4) Food Trial (if nonseasonal) 5) Environmental Allergy Testing/Allergy Immunotherapy +/- Antipruritic Therapy for Long- Term Management 7 Treatment Life-long conditions require life-long therapy Multimodal approach Tailored to the individual Threshold of pruritus https://www.petcoach.co/article/allergies-what- causes-scratching-the-pruritic-threshold/ Griffin, CE. Another allergic dog - Part I. Presented at the 2002 Wisconsin Veterinary Medical Association Convention, Milwaukee, WI. October 12, 2002. 8 4  9/21/24 Allergen-Specific Immunotherapy (ASIT) How it works (we think): Encourages a Th1 response Increases IFN𝛾 Promotes IgG that acts as a blocking antibody Increases Treg cells Helps suppress Th2 polarization Decreases Th2 cytokines (such as IL-4 and IL-5) Decreases tissue neutrophils, eosinophils, basophils and mast cells 9 ASIT Allergen selection is key Can administer as subcutaneous injection or sublingual drop Must teach owners Must have compliance Can take a year or so to START to help Does not work in every patient No real contraindications 10 5  9/21/24 Glucocorticoids Mechanism of action: Stabilize cell membranes (mast cells, eosinophils, etc.) Inhibit production of pro-inflammatory cytokines (IL-1, IL-6, TNF-∝, GM-CSF) Inhibit T cell function Decrease production and release of eicosanoids (reduces vascular permeability and vasodilation) Suppress myeloid cell activities Many potential side effects 11 Glucocorticoids Avoid in patients with: Previous demodicosis Liver disease Diabetes mellitus Hyperadrenocorticism Cardiac disease Current NSAID use Pregnancy/lactation Once-daily dosing effective Tapering protocols? 12 6  9/21/24 Glucocorticoids Steroid Potency (vs. Anti-inflammatory Duration of action Mineralocorticoid side prednisone) dose/day hours effects Prednisolone 1x 1mg/kg (d); 2mg/kg (c) 12-36 Methylprednisolone 1.25x 0.8mg/kg (d); 1.6mg/kg (c) 12-36 Triamcinolone 6-10x 0.2mg/kg (d); 0.4mg/kg (c) 36-48 Dexamethasone 10x 0.1mg/kg (d); 0.2mg/kg (c) 36-48 d=dog; c=cat 13 Glucocorticoids Methylprednisolone acetate (Dep-Medrol®) 20mg/cat given subcutaneously Watch frequency of administration Once you give it, you can’t take it back! 14 7  9/21/24 Side Effects of Glucocorticoids With short-term usage: PU/PD Polyphagia With long-term usage: Muscle wasting Pot-bellied Hypotrichosis/alopecia Diabetes mellitus https://www.zoetisus.com/products/dogs/apoquel/assets/pdf/apoqueltechnicalmonograph.pdf 15 Cyclosporine (Atopica™ / Cyclavance ™) Mechanism of action: Calcineurin inhibitor Inhibits T cell function (by blocking IL-2 transcription and T-cell responsiveness to IL-2) Side effects: vomiting/diarrhea; gingival hyperplasia Caution with drugs that inhibit P450 Ex. –azoles (will increase cyclosporine levels) Do not use with history of neoplasia or renal insufficiency, pregnancy/lactation Do not use in animals < 6 months of age Labeled dose 5mg/kg SID dog; 7mg/kg SID cat FeLV/FIV/toxoplasma status in cats? 16 8  9/21/24 Oclacitinib (APOQUEL®) Mechanism of action: JAK inhibitor Inhibits IL-2, IL-4, IL-6, IL-13, IL-31* Side effects: vomiting/diarrhea, lethargy, anorexia, polydipsia Caution with history of neoplasia? Don’t use with demodicosis, pregnancy, lactation Do not use in dogs < 12 months of age Labeled dose 0.4-0.6mg/kg BID for 14 days, then SID Not labeled for cats * Cytokine associated with pruritus in the dog 17 Lokivetmab (CYTOPOINT®) Mechanism of action: Monoclonal antibody (mAb) – neutralizes IL-31 Side effects - ? Not many restrictions for use Not for pregnancy/lactation NOT for use in cats!!!! Caninized antibody Can use every 28 days – use PRN Injectable – given in clinic 18 9  9/21/24 Antihistamines Mechanism of action: Blocks H1 receptors Side effects: sedation, hyperexcitability 2nd generation less sedating Caution in patients with liver disease, urinary retention, intestinal atony, pregnancy/lactation Not for rapid relief Not for severe pruritus May be steroid sparing 19 Others Fatty acids Modify prostaglandin and leukotriene synthesis May help with barrier function Pentoxifylline Phosphodiesterase inhibitor Multiple anti-inflammatory and immunomodulatory effects Side effects: GI most common, give with food Caution with bleeding disorders, liver/kidney issues, pregnancy, nursing 20 10  9/21/24 Outside-In vs. Inside-Out Treatment What role does a defective epidermal barrier play? Can we change this with topical therapy? Ceramides, FFA, glucocorticoids, etc. https://skinlibrary.co.uk/blogs/librarian-edits/skin-barrier 21 Topical Antipruritics Ingredients like hydrocortisone, pramoxine, oatmeal Shampoo, cream rinse, soak, spray, cream, ointment, dip Short-acting, limited relief Generally well-tolerated Caution with frequent, potent, topical steroid use 22 11  9/21/24 Topical Barrier Restoration Ingredients like ceramides, fatty acids, phytosphingosine Barrier restoration and repair Reasonable adjunctive therapy 23 Species-Specific Considerations Dogs Cytopoint® vs. Apoquel® response Cats Antihistamines more effective? Atopica® used more commonly Apoquel® is OFF-LABEL Cytopoint® is NOT an option Horses ASIT is very effective Apoquel®? Allergies w/ Reactive Airway Obstruction (RAO)? 24 12  9/21/24 Multifaceted Disease = Multifaceted Treatment! 25 Non-Derm Allergic Therapies Anaphylaxis Asthma Immediate action necessary Bronchodilators B2 adrenergic agonists Epinephrine Vasodilation of vessels around Smooth muscle heart and skeletal muscles, relaxation vasoconstriction of small vessels Glucocorticoids Increases heart rate & blood Antihistamines pressure Glucocorticoids Antihistamines +/- 26 13  9/21/24 Summary Allergies are the #1 reason pets are taken to the vet Many therapeutic interventions on the market None are perfect or work in every patient No “silver bullet” Targeted vs. broad-spectrum treatment for pruritus and inflammation Treat secondary problems (infections, ectoparasites) 27 Questions? 28 14