Antipruritic treatments 3 Flashcards
what are cyclosporines? use?
- Cyclosporines are drugs initially developed to prevent organ transplant rejection.
- Atopica is a cyclosporine licensed for the treatment of atopic dermatitis in the dog.
- Effective treatment for environmental allergies in dogs and cats as long as other factors are ruled out
- brand name generally better than generic
most common side effects of cyclosporines in dogs
intestinal upset, gingival hyperplasia and hypertrichosis.
- Papillomatosis is the next most common side effect that I see
- also, Plasmacytoma
petients where caution is necessary with cyclosporine
do not recommend the use of cyclosporine in patients with a history of tumours, and I use it with caution in the geriatric patient
contraindication for cyclosporine
contraindicated in the presence of neoplasia, patients with history of tumours
cyclosporine vs steroid treatment speed of response to therapy
It is important that the caregiver is advised that the rapid response to therapy obtained following initiation of steroid therapy is not seen with this drug.
- 4-6 wk minimum delayed response
cyclosporine dose, absorption, vomiting prevention, GI upset prevention
- in dogs at 5 mg/Kg per day
- Absorption is slightly better when administered on an empty stomach
- given with maripotant for first 4 days of treatment to prevent vomiting
- freezing the capsule before administration seems to reduce the incidence of GI upset
co-administration of cyclosporine with what other drug increases blood levels?
- Co-administration of ketoconazole increases the Atopica blood levels and the dose should be decreased accordingly
- This is a useful way of decreasing cost in the large dog
assessing the efficacy of cyclosporine over time? dose frequency?
- If there is a 50% or greater response at 4-6 weeks, there is a good chance that the patient will continue to improve and that the treatment frequency or dose can be decreased.
- Dose or frequency reduction is particularly important as the drug is quite expensive
> Once there is a significant response, the frequency can be slowly decreased
what should cats have before starting cyclosporine? what cats should not receive this drug? diet considerations?
- Cats should have a CBC done and be screened for FIV and FeLV prior to starting cyclosporine.
- Cats should not be fed raw diets when on Atopica.
- Cats at risk of contracting toxoplasma (outdoor cats, cats on a raw meat diet) should not be treated with this drug.
cyclosporine dose in cats
Syringe is dosed at 7 mg/Kg of cat
cyclosporine is approved for what conditions in cats
Approved for allergic dermatitis manifested by excoriations, eosinophilic plaques, miliary dermatitis and self-induced alopecia
possible issue of cyclosporine in young animals
Safety of the treatment in dogs less than 6 months of age has not been established. As gingival hyperplasia is a potential side effect, the use of the drug in patients with immature dentition can lead to problems.
cyclosporine mechanism of action
- Calcineurin inhibitor:
- By inhibition of calcineurin, cyclosporine specifically inhibits T-cell function, and thus cell-mediated immunity, but has little immediate impact on humoral immunity
- blocks transcription of T cell cytokines, such as IL-2, important in the activation and proliferation of T-lymphocytes
- also affected are interleukin 4, TNF-alpha, and interferon gamma
when to discontinue cyclosporine use in cats
The owner should be advised to discontinue if there is anorexia and/or weight loss as hepatic lipidosis has been reported in cats on Atopica Cat
tacrolimus - what is this drug? use? pros and cons?
- Like cyclosporine, tacrolimus is a calcineurin inhibitor, but with better tissue penetration
- alternative to steroids
- applied twice daily for the first week and then in reduced frequency.
- slow onset, not for flares
- initially application may lead to a burning sensation
- The patient should not be allowed to lick the area of administration for at least 20-30 minutes and small pets in particular should be watched to avoid ingestion as toxicity can occur.
- wear gloves when applying
- May not be cost effective unless there is clear evidence of thinning of the skin with steroid
treatment.
antihistamines use for pruritus
- not effective in ‘putting out the fire’
- useful in some cases:
- To control after the pruritus has been relieved (eg. with steroids)
- to reduce the steroid dose
- early in ‘season’ in dogs with seasonally recurring dermatitis
- very mildly affected individuals
which antihistamine is best to use for pruritus? cautions?
- best one is the one that works best
- Try each antihistamine for a period of 7-14 days each to assess response
- If using over the counter products, be sure to warn owners not to accidentally administer products that also contain decongestants, acetaminophen and the like.
- may have synergy with fatty acid supplementation
fatty acid supplementation for pruritus? use? how long do they take?
- 4-6 weeks to take effect
- more useful as adjunctive therpy
- “no evidence of superiority of any particular EFA combination, dose, ratio or formulation to improve skin and coat quality”
- supplement in diet
- high fatty acid diets recommended for non-food induced atopic dermatitis
gabapentin use for pruritus?
- This treatment has not been critically evaluated to date but is starting to gain traction in cases of intractable pruritus.
- mechanism of action is unknown, it appears to act where the itch pathways synapse by inhibiting the release of excitatory mediators
> The sensation of itch and pain are shared by the same neurons
Pentoxifylline, Misoprostol use for pruritus?
There is some evidence to support the use of these medications.
> suppress numerous cytokines, decreases leukocyte adhesion and aggregation and inhibits B and T cell activation
maropitant for pruritus use? mechanism
- Substance P is a mediator of pruritus.
- In people, an increase in the expression of its receptor, neurokinin-1, has been reported on keratinocytes in pruritic skin diseases
- Maripotant is a veterinary product that is a potent NK-1 receptor antagonist and is sold as Cerenia
> labeled for treatment of acute vomiting - trials for cases of severe intractable pruritus in dogs
Allergic conjunctivitis treatment options
- Cool compresses to eyes are an easy and often highly effective treatment for itchy eyes.
- some success with topical ocular NSAID, ketorolac
Allergic Otitis treatment options
- Gentle ear treatments are the mainstay of allergic ear treatment.
- remarkable success with compounded 2% Burows solution, 1% hydrocortisone, in Propylene Glycol
- Various treatments are available for the treatment of otitis externa in dogs and cats. Most are a combination of antibiotics, antifungal agents and steroids
Spot-On products for pruritus?
a complex lipid mixture (Allerderm Spot-on®) has been shown recently to help restore pre-existing ultrastructural lipid anomalies in a small number of dogs with atopy
Shampoo therapies for pruritus? use and efficacy?
- Bathing at least once weekly with a mild, non-irritatingshampoo and lukewarm water is likely to be beneficial
- The intensity and frequency of bathing may be the most important factor in relieving pruritus
<><> - Bathing offers a direct soothing effect to the skin, the physical removal of surface allergens and microbes and an increase in skin hydration
- The shampoo choice varies with the individual pet’s coat condition
- Ingredients that theoretically relieve pruritus include sulphur and salicylic acid, selenium sulfide, oatmeal and hydrocortisone
- If a concurrent microbial dermatitis is present, the use of shampoo containing antimicrobial ingredients such as chlorhexidine, ketoconazole, miconazole, climbazole or cetrimide are useful in controlling “flare factors.”
