Page 1472 - Clinical Small Animal Internal Medicine

1410 Section 12 Skin and Ear Diseases

nicotinamide, histidine, and inositol have been shown to efficacy. This microemulsion of the parent drug is more
VetBooks.ir possibly augment barrier function in healthy dogs by predictably absorbed and metabolized in the dog and cat
compared to nonmodified formulations.
increasing production of ceramide skin lipids; whether
Dosing is initially recommended to be 5–7 mg/kg PO
they have beneficial results in dogs with atopic dermati-
tis, however, is uncertain. As with some of the other con- q24h. Cats, particularly those with indolent ulcers, may
servative medical therapies, their most important benefit require a higher initial dose (7–10 mg/kg PO q24h) to
may be in the form of adjunct therapy for the disease, achieve initial beneficial results. When remission is
thereby decreasing the need for additional medical achieved, this dose or frequency of administration may
interventions. often be decreased while still achieving similar clinical
benefit on a long‐term basis. Although it is recom-
Glucocorticoids mended to be given on an empty stomach, administra-
Glucocorticoids have historically been touted as a main- tion with food has not been proven to alter clinical
stay therapy for atopic dermatitis in dogs and cats. Their improvement. Additionally, drug level monitoring is
efficacy in management of pruritus associated with the generally not indicated for the allergic patient; therapeu-
disease is without question; in fact, excellent response to tic drug levels do not typically correlate with clinical
glucocorticoid therapy can be a key factor in confirming improvement. Obtaining ciclosporin drug levels may,
a clinical diagnosis of atopic dermatitis. Strong evidence however, be beneficial in a dog or cat with a clinical
exists with regard to efficacy, particularly for controlling diagnosis of atopic dermatitis that is not responding
nonlocalized pruritus associated with atopic dermatitis. favorably to therapy.
Particularly for the acute flare, short‐course oral gluco- Compared to glucocorticoids, ciclosporin is generally
corticoid administration can be highly effective in man- better tolerated with fewer side‐effects, even long term.
aging the atopic patient. Recommended dosing for oral This is not to say that side‐effects do not occur; it is rec-
glucocorticoids (prednisone, prednisolone, methylpred- ommended to monitor basic internal health (e.g., com-
nisolone) is initiation of therapy at 0.5 mg/kg PO q12– plete blood count, serum biochemistry, urinalysis and
24h and then reducing to the lowest possible (ideally urine culture and sensitivity) every 6–12 months long
alternate‐day) dosing which provides sufficient comfort. term with continued ciclosporin administration. The
In cats, it is imperative that either prednisolone or meth- most commonly reported side‐effect is gastrointestinal
ylprednisolone be prescribed as most cats do not respond upset (e.g., vomiting, diarrhea, decreased appetite).
as well to the prodrug (prednisone). Additionally, allergic These side‐effects are typically self‐limiting and tran-
cats often require a higher initial dose (1–2 mg/kg PO sient; gastrointestinal upset will typically resolve within
q24h) for clinical effect. The use of long‐acting injectable 1–2 weeks of initiating therapy. Antinausea medication
glucocorticoids should be avoided for the management (e.g., maropitant) may be necessary in the short term to
of chronic inflammatory diseases such as atopic minimize undue patient discomfort.
dermatitis, as they have a much stronger effect on the Other less commonly reported side‐effects of ciclo-
hypothalamic‐pituitary‐adrenal axis. Moreover, their sporin include bacterial infections, bone marrow sup-
antipruritic/ antiinflammatory effect is not superior pression, hirsutism and excessive shedding, gingival
compared to oral short‐acting glucocorticoids. hyperplasia, hepatitis, papillomatosis, and seizures.
Although highly effective and cost‐effective (even for Additionally, in cats, acute and fatal toxoplasmosis has
large patients), the side‐effects of continued long‐term also been documented. It is recommended that cats
glucocorticoid administration are concerning. Clinicians remain indoors and not be fed a raw diet, be completely
are encouraged to consider and pursue alternative ther- restricted with regard to scavenging and hunting, and
apy for atopic dermatitis if glucocorticoid administration have serology documenting toxoplasma and feline leuke-
is necessary for several months of the year to provide mia virus/feline immunodeficiency virus (FeLV/FIV)
benefit. status prior to initiating therapy.
Ciclosporin levels in the blood may be influenced
Ciclosporin by concurrent administration of other medications.
As with glucocorticoids, there is strong evidence to sup- Ketoconazole and fluconazole, for example, can increase
port ciclosporin administration for management of the circulating ciclosporin levels via competitive binding
atopic dermatitis in dogs and cats. This calcineurin of the cytochrome P450 enzyme. Although this combi-
inhibitor more specifically targets T cell‐mediated nation can be clinically useful (e.g., allowing for lowered
inflammation associated with atopic dermatitis. It is dose of ciclosporin required to achieve clinical results,
important, however, to remember that the modified ver- thereby decreasing the cost of therapy), it can also
sion of the drug (e.g., Atopica®, Elanco Animal Health, increase the chance of side‐effects. Care must be taken
Indiana, USA) must be administered for predicted with other cytochrome P450‐associated medications