The Efficacy of L‐Deprenyl in Dogs with Pituitary‐Dependent Hyperadrenocorticism

Abstract

Ten dogs with pituitary-dependent hyperadrenocorticism (PDH) received 2 mg/kg of L-Deprenyl once daily for 6 months. Monthly patient assessment consisted of evaluation of the owner's daily observation protocol, a standardized owner questionnaire, physical examination, CBC, biochemical profile, determination of the urine cortisol/creatinine ratio (UC/C), low-dose dexamethasone suppression (LDDS) test, corticotropin releasing hormone (CRH) test, and adrenal ultrasonography. At the beginning and the end of the study, an adrenocorticotropic hormone (ACTH) stimulation test and computed tomography also were performed. Two dogs developed neurologic signs and 2 dogs developed acute pancreatitis. An increase in activity, decrease in polyphagia, and decrease in panting were reported by 6, 4, and 2 owners, respectively. Seven owners believed that water intake decreased, but this was confirmed in only 3 dogs. Water intake increased in 2 dogs and remained unchanged in 5 dogs. The condition of the hair coat and skin improved in 2 dogs, worsened in 3, and remained unchanged in 5. Urine specific gravity, urine osmolality, ACTH test results, UC/C, and adrenal gland size did not change significantly throughout the study. In 4 of 8 dogs, LDDS was abnormal at the start of the study but normal at the end of the study, and in 2 dogs, the opposite occurred. Marked individual variation was noted in the CRH test, with a tendency for smaller increases in ACTH toward the end of the study. A marked increase in hypophyseal tumor size occured in 4 dogs. Treatment with L-Deprenyl resulted in improvement, deterioration, and stagnation of clinical signs in 2, 4, and 4 dogs, respectively. The results of this study indicate that L-Deprenyl cannot be recommended as the sole treatment for canine PDH.

Efficacy of Low‐ and High‐Dose Trilostane Treatment in Dogs (< 5 kg) with Pituitary‐Dependent Hyperadrenocorticism

“…Among the drugs commonly used in the treatment of PDH is mitotane (o,p‐dichlorodiphenyldichloroethane), which has good efficacy but also potential adverse effects as well as disadvantages including transient hypoadrenocorticism, permanent mineralocorticoid and glucocorticoid deficiencies, drug intolerance, and a high frequency of relapse . Ketoconazole and L‐deprenyl also have been investigated for the treatment of PDH . The former is an imidazole derivative that interferes with cortisol synthesis by inhibiting cytochrome‐P‐450‐dependent enzymes.…”

“…In the few dogs thus far treated with ketoconazole, positive results have been obtained in the majority, but larger studies are needed and there are additional concerns regarding the potentially hepatotoxic effects of the drug . L‐deprenyl, a monoamine‐oxidase inhibitor, has been approved for the treatment of dogs with PDH in some countries, but is of limited efficacy …”

Diagnosis of Spontaneous Canine Hyperadrenocorticism: 2012 ACVIM Consensus Statement (Small Animal)

“…The primary indication for pursuing a diagnosis of HAC is the presence of one or more of the common clinical signs and physical examination findings ( Table 1). [1][2][3][4][5][6][7][8][9][10] If only 1 clinical sign is present, it is usually polyuria and polydipsia, or alopecia and skin changes suggestive of an endocrine disease. 11 Cases seen by dermatologists may have a different constellation of findings than those seen by internists.…”

“…Clinical manifestations of canine HAC. [1][2][3][4][5][6][7][8][9][10][11][111][112][113] Categorization of frequency is based on identification at the time of initial presentation.…”

Use of ketoconazole to treat dogs with pituitary-dependent hyperadrenocorticism: 48 cases (1994–2007)

“…1,2 Current treatments for dogs with PDH include a group of clinically evaluated drugs, only some of which effectively control the disorder. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Ketoconazole, cyproheptadine, aminoglutethimide, and L-deprenyl are used for treatment, but studies [17][18][19][20][21][22] in which the effectiveness of these drugs has been evaluated are limited and incomplete. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Ketoconazole, cyproheptadine, aminoglutethimide, and L-deprenyl are used for treatment, but studies [17][18][19][20][21][22] in which the effectiveness of these drugs has been evaluated are limited and incomplete.…”