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Objectives To investigate kidney function by determining serum symmetric dimethylarginine (sSDMA) and serum creatinine (sCr) concentrations in dogs with primary hypoadrenocorticism (PH) receiving long-term mineralocorticoid replacement therapy. Methods Dogs with PH receiving a minimum of 12 months of either desoxycorticosterone pivalate or fludrocortisone acetate were included in the study provided that banked frozen serum samples were available for sSDMA analysis. sCr concentrations were retrieved from the medical records. In dogs still alive and presented for regular re-evaluations and in newly diagnosed patients, blood was prospectively collected for sSDMA and sCr determination. Results Thirty-two dogs met the inclusion criteria. The treatment time ranged from 12 to 146 months after initial diagnosis (median, 55.5 months). The majority of dogs had normal sSDMA and sCr concentrations throughout the hormone replacement treatment. Both sSDMA and sCr concentrations were persistently elevated in three of 32 dogs. Further workup confirmed chronic kidney disease (CKD) in all three dogs. Conclusions Based on these data, the prevalence of CKD could be higher in dogs with PH receiving long-term mineralocorticoid replacement treatment than in the general dog population. However, additional studies with a larger number of dogs are needed to confirm it.

Background Lowering the dose of desoxycorticosterone pivalate (DOCP) for the treatment of dogs with primary hypoadrenocorticism (PH) decreases costs and could lead to increased owner motivation to treat their affected dogs. Objective To evaluate the efficacy of a low-dose DOCP treatment protocol in dogs with PH. Animals Prospective study, 17 client-owned dogs with naturally occurring PH (12 newly diagnosed, 5 previously treated with fludrocortisone acetate [FC]). Methods Dogs with newly diagnosed PH were started on 1.5 mg/kg DOCP SC; dogs previously treated with FC were started on 1.0-1.8 mg/kg DOCP SC. Reevaluations took place at regular intervals for a minimum of 3 months and included clinical examination and determination of serum sodium and potassium concentrations. The DOCP dosage was adjusted to obtain an injection interval of 28-30 days and to keep serum electrolyte concentrations within the reference interval. Results Median (range) follow-up was 16.2 months (4.5-32.3 months). The starting dosage was sufficient in all but 2 dogs and had to be significantly decreased after 2-3 months to a median dosage (range) of 1.1 mg/kg (0.7-1.8). Dogs 3 years of age or younger needed significantly higher dosages compared to older dogs. None of them, however, needed the 2.2 mg/kg DOCP dosage, recommended by the manufacturer. Conclusions and clinical importance A starting dosage of 1.5 mg/kg DOCP is effective in controlling clinical signs and serum electrolyte concentrations in the majority of dogs with PH. An additional dose reduction often is needed to maintain an injection interval of 28-30 days. Young and growing animals seem to need higher dosages.

Although newly introduced to the UK and EU markets, desoxycorticosterone pivalate (DOCP) has been used successfully for the management of canine hypoadrenocorticism in the US for several decades. This article briefly reviews the history of DOCP use, as well as current dosing and monitoring recommendations, including off-label recommendations for lower initial dosing. Laboratory quality, particularly when using electrolyte ratios, is a critical component of case management.

Background Clinicians alter dosing for desoxycorticosterone pivalate (DOCP) to mitigate costs, but this practice has not been critically evaluated in a prospective clinical trial. Hypothesis/Objectives The duration of action of DOCP is longer than 30 days in dogs with primary hypoadrenocorticism (PH). Animals A total of 53 client-owned dogs with PH. Twenty-four dogs with newly diagnosed PH (Group 1) and 29 dogs with treated PH (Group 2). Methods Prospective, multicenter, clinical trial. For phase I, DOCP was administered and plasma sodium and potassium concentrations were measured until the dog developed hyponatremia or hyperkalemia at a planned evaluation, or displayed clinical signs with plasma electrolyte concentrations outside of the reference interval independent of a planned evaluation, thus defining DOCP duration of action. Plasma electrolyte concentrations then were assessed at the end of the individualized dosing interval (IDI; i.e., DOCP duration of action minus 7 days, phase II and at least 3 months after concluding phase II, phase III). Results The duration of action of DOCP in dogs in phase I with naive PH (n = 24) ranged from 32 to 94 days (median, 62 days; 95% confidence interval [CI], 57, 65) and previously treated PH (n = 29) from 41 to 124 days (median, 67 days; CI, 56, 72). Overall, the final DOCP dosing interval for all dogs that completed phase II (n = 36) ranged from 38 days to 90 days (median, 58 days; CI, 53, 61). No dog that completed phase III (n = 15) required reduction in the IDI. The DOCP duration of action, independent of group, was not significantly associated with several baseline variables. The median drug cost reduction using IDI was approximately 57.5% per year. Conclusion and Clinical Importance The duration of action of DOCP in dogs with PH is >30 days, and plasma sodium and potassium concentrations can be maintained with an IDI >30 days long term.

ADDISON'S disease or hypoadrenocorticism generally results from immune-mediated destruction of the adrenal glands and particular dog breeds appear to be overrepresented; for example, West Highland white and wheaten terriers, Portuguese water dogs, duck-tolling retrievers and great danes. Candidate genes for the disease have been identified in several breeds, although at this time the exact contribution of these genes is unclear (Short and others 2014). In most cases of ‘typical’ hypoadrenocorticism there is a lack of production of both mineralocorticoid and glucocorticoid, whereas in the rarer ‘atypical’ Addisonian only glucocorticoid deficiency manifests itself. Mineralocorticoid deficiency results in hyponatraemia and hyperkalaemia, as well as hypovolaemia, whereas glucocorticoid deficiency can lead to weakness, hypoglycaemia and gastrointestinal signs. Once typical hypoadrenocorticism has been diagnosed, both mineralocorticoid and glucocorticoid supplementation is needed. Mineralocorticoid deficiency is generally treated with either fludrocortisone or desoxycorticosterone pivalate (DOCP). There is an example of a large study of 205 dogs where 95 per cent were initially treated with fludrocortisone. Some of these dogs (14 per cent) were eventually switched to DOCP for a variety of reasons (Kintzer and Peterson 1997). In a paper summarised on p 98 of this issue of Veterinary Record , Roberts and others (2016) were also able to successfully stabilise 90 per cent of their patients with fludrocortisone. There are significant differences between both medications, including cost, and in most countries DOCP is sparingly used, because it is considerably more expensive than fludrocortisone; however, in a small number of countries …