# Canine Hypoadrenocorticism: Diagnostic and Therapeutic Monitoring ## Key Takeaways - Long-term management of canine hypoadrenocorticism necessitates independent monitoring of mineralocorticoid and glucocorticoid replacement axes, focusing on electrolyte homeostasis and glucocorticoid adequacy, respectively. - Electrolyte monitoring (serum sodium, potassium, and their ratio) is paramount for mineralocorticoid replacement adequacy, with persistent hyponatremia or hyperkalemia indicating under-replacement, and targets serum sodium within the reference interval and a sodium:potassium ratio above 27:1. - Glucocorticoid replacement is primarily guided by clinical signs such as appetite, body weight, and energy level, as routine ACTH stimulation testing is not indicated for monitoring post-adrenal destruction, and over-replacement can manifest as polyuria and polydipsia. - Crisis prevention hinges on owner education regarding stress dosing of glucocorticoids during illness or injury, as mineralocorticoid replacement alone does not provide adequate stress cover, and prompt recognition of early clinical signs like lethargy or vomiting is crucial. - Structured monitoring schedules, including regular assessment of body weight, blood pressure, and owner-reported clinical signs, alongside electrolyte panels timed relative to the dosing schedule, are essential for early detection of treatment drift and prevention of addisonian crises. - Reconsideration of the diagnosis is warranted in dogs requiring escalating doses or failing to stabilize, with basal cortisol levels above 55 nmol/L (2 μg/dL) effectively excluding glucocorticoid deficiency and prompting further investigation. --- This article addresses the long-term management and monitoring of canine hypoadrenocorticism after the diagnosis has been confirmed. It serves the practicing veterinarian who must adjust maintenance therapy, recognize and manage an addisonian crisis, and prevent relapse through structured surveillance. The focus is on treatment adjustment, electrolyte monitoring, and crisis prevention, with the assumption that the reader has already established the diagnosis through ACTH stimulation testing or basal cortisol assessment. The clinical challenge in managing affected dogs is balancing mineralocorticoid and glucocorticoid replacement against the risks of overtreatment, undertreatment, and intercurrent illness. Hypoadrenocorticism typically results from immune-mediated destruction of all adrenocortical layers, producing deficiencies of both aldosterone and cortisol, although a small number of dogs have glucocorticoid deficiency alone [Klein and Peterson on the pathophysiology of canine hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/20357943/). Monitoring therefore targets two distinct axes: electrolyte homeostasis and glucocorticoid adequacy, each with its own pitfalls. ## At a Glance | Parameter | Target or Threshold | Monitoring Frequency | Action Trigger | |---|---|---|---| | Serum sodium | Within reference interval | 1 to 2 weeks after dose change, then every 3 to 6 months | Persistent hyponatremia suggests under-replacement | | Serum potassium | Within reference interval | Same as sodium | Persistent hyperkalemia suggests under-replacement | | Sodium:potassium ratio | Above 27:1 | Same as sodium | Ratio below 27:1 warrants evaluation | | Basal cortisol | ≤55 nmol/L (2 μg/dL) supports diagnosis, >55 nmol/L excludes it | At diagnosis only | Not used for routine monitoring | | Body weight | Stable or appropriate gain | Every visit | Unexplained loss may signal under-replacement | | Owner-reported polyuria or polydipsia | Absent | Every visit | May indicate glucocorticoid over-replacement | | ACTH stimulation test | Post-ACTH cortisol within reference interval | Not routinely indicated for monitoring | Reserved for suspected glucocorticoid over- or under-treatment | | Blood pressure | Normotensive | Every 6 to 12 months | Hypertension may indicate mineralocorticoid over-replacement | ## Pathophysiology Relevant to Monitoring The adrenal cortex produces aldosterone under the control of the renin-angiotensin-aldosterone system and cortisol under the control of ACTH. In typical hypoadrenocorticism, both are deficient. Aldosterone deficiency impairs renal sodium reabsorption and potassium excretion, leading to hyponatremia, hyperkalemia, and hypovolemia. Cortisol deficiency contributes to hypotension, gastrointestinal signs, and an impaired stress response. The clinical signs are nonspecific and may mimic other diseases, which is why hypoadrenocorticism has been called "the great pretender" [Klein and Peterson on the diagnostic challenge of canine hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/20357943/). Monitoring must account for the fact that the two hormone axes are replaced independently. Mineralocorticoid replacement corrects electrolyte abnormalities but does not provide glucocorticoid cover. Glucocorticoid replacement at physiologic doses does not correct electrolyte disturbances. A dog receiving only one replacement may appear stable on routine bloodwork yet remain vulnerable to crisis during stress. ## Basal Cortisol and the Limits of Diagnostic Thresholds Basal cortisol measurement is a diagnostic tool, not a monitoring tool, but its interpretation informs how aggressively a clinician pursues treatment adjustment. In a large retrospective evaluation of 522 dogs, a basal cortisol concentration of ≤55 nmol/L (2 μg/dL) had a sensitivity of 99.4% for hypoadrenocorticism, while the most discriminatory cut-point of 22 nmol/L (0.8 μg/dL) gave sensitivity and specificity of 96.9% and 95.7%, respectively [Gold, Langlois, and Refsal on basal cortisol for diagnosing hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/27714859/). These thresholds are useful when a dog with known hypoadrenocorticism presents with a suspected relapse or when a newly treated dog fails to improve. A basal cortisol above 55 nmol/L effectively excludes glucocorticoid deficiency and redirects the diagnostic search toward other causes of the clinical signs. ## The Two Replacement Axes ### Mineralocorticoid Replacement Two mineralocorticoid options are available: fludrocortisone acetate, an oral mineralocorticoid with some glucocorticoid activity, and desoxycorticosterone pivalate (DOCP), an injectable mineralocorticoid. The choice between them depends on owner compliance, cost, and the dog's response. Fludrocortisone requires twice-daily oral administration and may cause polyuria or polydipsia at higher doses. DOCP is given by injection every 21 to 30 days and avoids daily oral dosing, but it requires clinic visits or owner-administered injections. Current formulary and label references must be consulted for dosing, as individual requirements vary substantially. Electrolyte monitoring is the central element of mineralocorticoid adjustment. Serum sodium and potassium should be measured 1 to 2 weeks after initiating therapy or changing the dose. For DOCP, electrolytes are typically checked just before the next injection to confirm the dosing interval is appropriate. Persistent hyponatremia or hyperkalemia indicates under-replacement, while hypernatremia or hypokalemia suggests over-replacement. The sodium:potassium ratio is a useful adjunct but should not replace individual electrolyte assessment. ### Glucocorticoid Replacement Prednisolone or hydrocortisone is used for glucocorticoid replacement. The goal is to provide physiologic cover without inducing iatrogenic hyperadrenocorticism. Clinical indicators of adequate replacement include normal appetite, stable body weight, and resolution of lethargy or gastrointestinal signs. Over-replacement produces polyuria, polydipsia, panting, and weight gain. Under-replacement manifests as lethargy, poor appetite, and vomiting. Routine ACTH stimulation testing is not indicated for monitoring glucocorticoid replacement. The test measures the adrenal response to exogenous ACTH, which is irrelevant once the adrenal cortex has been destroyed. Instead, clinical assessment and owner history guide dose adjustment. A dog receiving both mineralocorticoid and glucocorticoid replacement may develop signs of glucocorticoid excess if the prednisolone dose is too high, even when electrolytes are normal. ## The Addisonian Crisis An addisonian crisis is a medical emergency characterized by hypovolemic shock, severe electrolyte derangements, and potentially life-threatening hyperkalemia. It occurs when a dog with hypoadrenocorticism is undertreated, when glucocorticoid cover is inadequate during stress, or when the disease is first presenting. The management of an established crisis requires intravenous fluid therapy, glucocorticoid administration, and correction of electrolyte abnormalities. Specific infusion rates and drug doses must be obtained from current emergency references and formularies. Crisis prevention depends on owner education and a clear sick-day protocol. Owners must understand that glucocorticoid doses should be increased during illness, injury, or other stress, and that mineralocorticoid replacement alone does not provide stress cover. The [ACVIM consensus statements on endocrine disease management](https://www.acvim.org/Animal-Owners/Animal-Education/Consensus-Statements) provide a framework for these protocols, though specific recommendations vary by institution. The [MSD Veterinary Manual](https://www.msdvetmanual.com/) also offers practical guidance on emergency management and owner instructions. ## Monitoring Schedule and Long-Term Surveillance A structured monitoring schedule reduces the risk of crisis and catches treatment drift early. After diagnosis and stabilization, electrolytes should be rechecked at 1 to 2 weeks, then at 4 weeks, then every 3 to 6 months. Body weight, hydration status, and blood pressure should be assessed at each visit. Owners should be questioned specifically about polyuria, polydipsia, appetite, energy level, and any episodes of vomiting or diarrhea, as these are the earliest indicators of decompensation. Vomiting is a common presenting sign in small animal practice and warrants particular attention in the Addisonian dog [Elwood et al. on the approach to emesis in dogs](https://pubmed.ncbi.nlm.nih.gov/20137004/). A single episode of vomiting in a dog with hypoadrenocorticism may be benign, but repeated vomiting, especially with lethargy or collapse, should prompt immediate electrolyte measurement and consideration of crisis management. The threshold for recommending an emergency visit should be low. Blood pressure monitoring is often overlooked. Mineralocorticoid over-replacement can cause hypertension, while under-replacement causes hypotension. Both are clinically significant. Hypertension should prompt a reduction in mineralocorticoid dose, while hypotension may indicate under-replacement or concurrent glucocorticoid deficiency. The [AVMA practice resources on preventive care and chronic disease monitoring](https://www.avma.org/resources-tools) emphasize the value of routine vital parameter assessment in chronic disease management. ## When to Reconsider the Diagnosis A dog with confirmed hypoadrenocorticism that requires escalating doses of both replacements, or that fails to stabilize despite appropriate therapy, warrants reevaluation. Possible explanations include concurrent disease, owner noncompliance, or an incorrect initial diagnosis. Basal cortisol measurement can help: a value above 55 nmol/L (2 μg/dL) effectively excludes glucocorticoid deficiency and suggests the original diagnosis was wrong [Gold, Langlois, and Refsal on basal cortisol thresholds](https://pubmed.ncbi.nlm.nih.gov/27714859/). In such cases, repeat ACTH stimulation testing may be indicated, and the differential diagnosis should be revisited. ## Monitoring Parameters and Their Clinical Meaning The electrolyte panel remains the central monitoring tool for mineralocorticoid adequacy. Sodium and potassium concentrations should be assessed together, because the ratio between them often reveals disturbances before either value falls outside the reference interval. A sodium-to-potassium ratio below 27 warrants scrutiny even when individual values remain within published limits, although the ratio should never replace direct evaluation of both electrolytes. Serial measurements allow the clinician to distinguish transient fluctuation from a genuine trend. A single mildly elevated potassium concentration in an otherwise stable dog rarely justifies a dose change. Two consecutive measurements trending upward, or a single measurement accompanied by weakness or vomiting, carries more weight. The same logic applies to sodium: a gradual decline toward the lower reference limit matters more than an isolated low-normal value. Clinical signs provide the context that transforms laboratory data into a treatment decision. Polyuria and polydipsia often emerge early when mineralocorticoid replacement becomes insufficient. Weakness, lethargy, and reduced appetite follow as electrolyte derangements worsen. Gastrointestinal signs, particularly vomiting, can indicate either glucocorticoid or mineralocorticoid insufficiency and require prompt assessment, as vomiting is a common presenting sign in small animal practice and carries consequences that extend beyond the inciting cause [Emesis in dogs: a review](https://pubmed.ncbi.nlm.nih.gov/20137004/). Body weight serves as an inexpensive and reliable adjunct. A dog that gains weight rapidly after a dose increase may be receiving excessive mineralocorticoid, with hypertension as a potential consequence. Weight loss in a previously stable dog should prompt evaluation for under-replacement before other causes are pursued. ## The Monitoring Visit: Structure and Interpretation A structured recheck examination provides the framework for dose adjustment. The visit should include body weight, blood pressure measurement, and a focused history covering thirst, urination frequency, appetite, energy level, and any vomiting or diarrhea. The physical examination should note mucous membrane color, pulse quality, and hydration status. The electrolyte panel should be timed relative to the dosing schedule. For dogs receiving oral fludrocortisone, sampling at a consistent interval after the morning dose reduces variability. For dogs receiving injectable desoxycorticosterone pivalate (DOCP), the timing of sampling relative to the injection carries greater significance. Sampling in the week before the next scheduled injection captures the trough of the dosing interval and provides the most conservative assessment of mineralocorticoid coverage. Sampling shortly after injection may overestimate the adequacy of the dosing interval. The following table summarizes the parameters assessed at each monitoring visit and the action each finding supports. | Parameter | What It Detects | Action Threshold | Dose Adjustment | | --- | --- | --- | --- | | Serum potassium | Mineralocorticoid under-replacement | Above reference interval on two consecutive visits, or one elevation with clinical signs | Increase mineralocorticoid dose | | Serum sodium | Mineralocorticoid under-replacement | Below reference interval, or declining trend across visits | Increase mineralocorticoid dose | | Sodium-to-potassium ratio | Early mineralocorticoid imbalance | Below 27 with clinical signs | Recheck in 1 to 2 weeks, adjust if trend continues | | Body weight | Over-replacement or under-replacement | Gain of more than 5% since last visit | Evaluate blood pressure, consider reducing dose if hypertensive | | Blood pressure | Mineralocorticoid over-replacement | Systolic above 160 mmHg | Reduce mineralocorticoid dose | | Clinical signs (polyuria, polydipsia, weakness) | Either axis insufficiency | Any new or recurring sign | Full reassessment, including electrolytes and cortisol profile | | Owner-reported vomiting | Glucocorticoid or mineralocorticoid insufficiency | Any episode in a previously stable dog | Prompt electrolyte assessment, consider stress-dose glucocorticoid | ## Fludrocortisone Versus DOCP: Selection and Switching The choice between fludrocortisone acetate and DOCP depends on owner compliance, cost, and the individual dog's response. Fludrocortisone is administered orally twice daily, which suits owners who can commit to a consistent medication schedule. DOCP is administered by injection every 21 to 30 days, which reduces the daily medication burden but requires regular veterinary visits. Dose requirements for fludrocortisone often increase during the first year of treatment. This phenomenon is well recognized and does not indicate treatment failure. The clinician should anticipate the need for upward adjustment and should not interpret a rising dose requirement as evidence of a wrong diagnosis. DOCP doses tend to stabilize more quickly, although individual variation is considerable. Switching between agents is straightforward when the indication is owner convenience or cost. The switch requires a washout period only in the sense that the new agent must be given its full dose from the start. A dog moving from fludrocortisone to DOCP should receive its first DOCP injection on the day the fludrocortisone is discontinued. A dog moving from DOCP to fludrocortisone should begin oral therapy at the time the next injection would have been due. Electrolytes should be checked 7 to 10 days after the switch and again at the next scheduled interval. ## Glucocorticoid Monitoring and Stress Dosing Glucocorticoid replacement is monitored primarily through clinical response instead of laboratory testing. Cortisol measurements during treatment are difficult to interpret because exogenous glucocorticoids cross-react with most assays. The clinician should rely on appetite, energy, and the absence of glucocorticoid deficiency signs such as vomiting, diarrhea, or lethargy. The distinction between maintenance glucocorticoid requirements and stress requirements is central to long-term management. Owners must understand that a dog receiving maintenance glucocorticoid replacement cannot mount an adequate cortisol response to illness or injury. The clinician should provide clear written instructions for stress dosing, specifying that the dose should be increased during intercurrent illness, before elective procedures, and after trauma. The exact stress dose should be confirmed against a current formulary reference before it is communicated to the owner. Gastrointestinal illness creates a particular challenge. A dog that is vomiting cannot retain oral glucocorticoid, and the clinician must decide whether injectable glucocorticoid is warranted. This decision should be made early instead of after the dog has deteriorated. The threshold for injectable glucocorticoid should be low in any Addisonian dog with vomiting, because the consequences of under-treatment are more severe than the consequences of a single extra dose. ## Long-Term Surveillance and Crisis Prevention The monitoring schedule should be individualised, but a reasonable framework begins with electrolyte assessment at 1, 2, and 4 weeks after diagnosis or any dose change. Once stabilized, rechecks every 3 to 6 months are appropriate for most dogs. Annual visits should include a complete blood count, biochemistry panel, and urinalysis in addition to electrolytes. Crisis prevention depends on owner education as much as on laboratory monitoring. Owners should recognize the early signs of hypoadrenocorticism: lethargy, weakness, reduced appetite, vomiting, and increased thirst. They should know when to administer stress-dose glucocorticoid and when to seek veterinary care. The practice should document that this education was provided and should revisit it at each recheck. The differential diagnosis for a dog that deteriorates despite apparently adequate replacement includes gastrointestinal disease, pancreatitis, and other intercurrent illness. Hypoadrenocorticism does not confer immunity to other diseases, and the clinician should not attribute every new sign to the endocrine condition. A dog with persistent vomiting and normal electrolytes requires investigation for other causes, guided by the same diagnostic reasoning applied to any vomiting dog [Emesis in dogs: a review](https://pubmed.ncbi.nlm.nih.gov/20137004/). The prognosis for canine hypoadrenocorticism is good when treatment is consistent and monitoring is regular. Most dogs return to normal activity and lifespan. The clinician's role is to maintain the balance between under-replacement, which risks crisis, and over-replacement, which risks hypertension and polyuria. That balance is achieved through disciplined monitoring, clear owner communication, and a willingness to adjust treatment based on trends instead of single measurements. ## Recognized Complications and Early Detection The principal long-term complications of treated hypoadrenocorticism are iatrogenic over-replacement, breakthrough hypoadrenocorticism, and glucocorticoid withdrawal effects. Each has a distinct monitoring signature. Mineralocorticoid over-replacement produces hypertension, polyuria, polydipsia, and, in severe cases, edema or cardiac strain. Serial blood pressure measurement and body weight tracking detect this earlier than owner observation alone. Under-replacement presents with the familiar triad of lethargy, vomiting, and electrolyte derangement, but the earliest sign is often a gradual rise in potassium or fall in sodium that precedes clinical deterioration by days. The [ACVIM consensus statements](https://www.acvim.org/Animal-Owners/Animal-Education/Consensus-Statements) emphasize that electrolyte checks should be timed to the expected peak and trough of the mineralocorticoid dosing interval, not performed at random. Glucocorticoid over-replacement is subtler. Polydipsia, panting, muscle wasting, and behavioral change may be dismissed as unrelated in an older dog. The discriminating finding is that these signs resolve when the dose is tapered. Glucocorticoid under-replacement, by contrast, may present as vague lethargy or poor stress tolerance. Owners often report that the dog "crashes" after boarding, travel, or a household disruption. This pattern indicates the maintenance dose is marginal and the stress plan is inadequate. A less common but serious complication is recurrence of crisis despite apparently adequate replacement. This should trigger a search for intercurrent disease, medication changes, or owner non-adherence. Gastrointestinal disease that impairs absorption of oral fludrocortisone is a recognized cause of decompensation, and the vomiting dog on oral mineralocorticoid is at particular risk, as reviewed in the [emesis literature in dogs](https://pubmed.ncbi.nlm.nih.gov/20137004/). ## Common Errors and Corrective Action The most frequent error in long-term management is treating the electrolyte panel instead of the whole patient. A dog with normal sodium and potassium but persistent lethargy may be glucocorticoid-deficient, and no mineralocorticoid adjustment will fix that. Conversely, chasing a borderline potassium with escalating fludrocortisone doses can produce hypertension before the potassium normalizes. A second error is failing to distinguish between the two replacement axes when a problem arises. An owner who reports vomiting and weakness in a dog on DOCP will often receive an extra glucocorticoid dose, which is appropriate, but the clinician must also consider whether the DOCP injection is due or whether the dose needs adjustment. The reverse error, increasing mineralocorticoid when the dog is actually glucocorticoid-deficient, is equally common. A third error is over-interpreting a single cortisol measurement. Basal cortisol has excellent negative predictive value, but a low-normal result does not confirm adequate replacement, and a single high value may reflect stress instead of over-replacement. The [evaluation of basal cortisol concentrations](https://pubmed.ncbi.nlm.nih.gov/27714859/) demonstrates that thresholds are diagnostically useful but must be interpreted in clinical context. Less experienced clinicians also tend to under-dose glucocorticoid during intercurrent illness. The stress dose plan should be reviewed at every visit, and the owner should be able to state it back correctly. If they cannot, the plan is too complicated. ## Limitations of the Evidence and Areas of Disagreement The evidence base for monitoring protocols is largely empirical. There are no prospective trials comparing monitoring intervals, and the recommended electrolyte checks at two to four weeks after dose changes, then every three to six months, rest on expert opinion instead of outcome data. The [MSD Veterinary Manual](https://www.msdvetmanual.com/) reflects this by presenting monitoring schedules as guidance instead of protocol. Expert opinion differs on several points. The target sodium to potassium ratio is debated, with some clinicians accepting a ratio above 27 and others insisting on full normalization. The role of aldosterone measurement during treatment is unsettled, and plasma renin activity, while informative in research settings, is not widely available clinically. Whether DOCP or fludrocortisone is superior for long-term stability remains contested, with the choice often resting on owner compliance, cost, and clinician familiarity. There is genuine uncertainty about the optimal glucocorticoid stress protocol. The traditional recommendation to double or triple the maintenance dose during illness is not supported by pharmacokinetic data, and some specialists now favour a fixed "sick day" dose instead of a multiplier. This is an area where [veterinary consensus guidance](https://www.acvim.org/Animal-Owners/Animal-Education/Consensus-Statements) acknowledges the evidence gap. ## Referral, Consultation, and Reporting Most dogs with hypoadrenocorticism are managed successfully in primary care practice. Referral to an internal medicine specialist is warranted when the diagnosis is secure but the dog remains unstable on two or more dose adjustments, when atypical presentations such as glucocorticoid-deficient-only disease are suspected, or when concurrent endocrinopathy complicates management. Specialist input is also valuable when the clinician is considering a switch between mineralocorticoid formulations and wants a second opinion on the transition plan. Laboratory involvement is appropriate when electrolyte results do not match the clinical picture, when assay interference is suspected, or when a dog with previously stable disease develops unexplained laboratory abnormalities. A veterinary clinical pathologist can advise on sample handling, assay selection, and interpretation of borderline results. Regulatory reporting is rarely relevant in the management of naturally occurring hypoadrenocorticism. It becomes relevant only if a suspected adverse drug reaction to a licensed product is observed, in which case the national pharmacovigilance scheme should be notified. The [AVMA practice resources](https://www.avma.org/resources-tools) provide guidance on adverse event reporting obligations in the United States, and clinicians elsewhere should consult their local regulatory authority. ## Troubleshooting Guide | Observation | Likely cause | Discriminating check | |---|---|---| | Persistent polyuria and polydipsia on stable dose | Mineralocorticoid over-replacement | Blood pressure, body weight, sodium above reference | | Lethargy with normal electrolytes | Glucocorticoid under-replacement | Trial of increased glucocorticoid, cortisol profile | | Vomiting and weakness before DOCP injection is due | Dose interval too long or dose too low | Pre-injection electrolytes, clinical response to earlier injection | | Hypertension on fludrocortisone | Dose too high or sodium intake excessive | Blood pressure, dietary history, dose reduction trial | | Recurrent crises despite reported adherence | Malabsorption, intercurrent disease, or non-adherence | Direct questioning, gastrointestinal work-up, observed dosing | | Poor stress tolerance during minor illness | Inadequate stress protocol | Review sick-day plan, owner comprehension check | ## Frequently Asked Questions ### How Do I Manage a Suspected Addisonian Crisis When Point-of-Care Electrolyte Testing Is Unavailable? Begin treatment based on history, physical examination, and any available laboratory data. Hypoadrenocorticism has been called "the great pretender" because it mimics other diseases, so crisis management often proceeds on clinical suspicion [Klein and Peterson on canine hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/20357943/). Collect blood for a basal cortisol sample before administering glucocorticoids, since exogenous steroid will confound later interpretation. Submit serum for a complete biochemistry panel and electrolytes to the reference laboratory, but do not delay fluid resuscitation and parenteral glucocorticoid administration while awaiting results. If the dog responds poorly to initial therapy, reconsider alternative diagnoses, including sepsis, gastrointestinal foreign body, or portosystemic shunting, which can present with similar clinical signs [review of congenital portosystemic shunts](https://pubmed.ncbi.nlm.nih.gov/36851464/). ### What Electrolyte Targets Should Guide Mineralocorticoid Dose Adjustments During the First Months of Therapy? Measure sodium and potassium concentrations at each recheck during the stabilization period, typically every one to two weeks initially, then monthly until values are stable. The goal is to maintain sodium and potassium within the reference interval while avoiding iatrogenic hypernatremia or hypokalemia. Adjust the mineralocorticoid dose in small increments and recheck electrolytes within seven to ten days of any change. A basal cortisol concentration can be useful during this period to confirm the original diagnosis if there is doubt, but it does not guide mineralocorticoid dosing [evaluation of basal cortisol for diagnosis of hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/27714859/). Once two consecutive stable electrolyte panels are obtained, extend the interval between rechecks. ### How Should I Handle Glucocorticoid Supplementation When a Stabilized Addisonian Dog Develops a Minor Illness? Instruct owners to double or triple the oral glucocorticoid dose on the first day of a febrile illness, vomiting, diarrhea, or significant stress, and to contact the clinic if signs persist beyond 24 hours. Vomiting is a common presenting sign in small animal practice and may indicate that oral medication is not being absorbed [review of emesis in dogs](https://pubmed.ncbi.nlm.nih.gov/20137004/). If the dog cannot retain oral glucocorticoids, injectable dexamethasone or prednisolone should be administered and the dog examined promptly. Owners should never omit glucocorticoid doses during illness. After the stressful event resolves, return to the maintenance dose without a tapering schedule for short courses of two to three days. ### What Are the Practical Differences in Monitoring Between Fludrocortisone and DOCP That Affect My Clinic Workflow? Fludrocortisone requires daily oral administration and more frequent electrolyte monitoring during stabilization because absorption and potency vary between dogs. DOCP is injected every 21 to 30 days, which improves owner compliance but requires the dog to visit the clinic for each injection and electrolyte check. With DOCP, electrolytes are typically measured before the next injection to determine whether the interval should be shortened or lengthened. With fludrocortisone, electrolytes are checked at each recheck and the daily dose adjusted accordingly. Both drugs require glucocorticoid co-administration in most dogs, since neither provides adequate cortisol replacement [Klein and Peterson on canine hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/20357943/). Clinic scheduling, owner travel distance, and the dog's temperament should inform the choice. ### How Do I Distinguish Poor Electrolyte Control From Inadequate Glucocorticoid Replacement in a Dog That Remains Polyuric and Polydipsic? Measure serum sodium, potassium, and cortisol response to ACTH stimulation if glucocorticoid adequacy is in question. Persistent polyuria and polydipsia with normal electrolytes suggests glucocorticoid under-replacement, whereas hyperkalemia or hyponatremia points to mineralocorticoid insufficiency. A basal cortisol concentration below 22 nmol/L supports ongoing glucocorticoid deficiency, although this threshold was derived from diagnostic instead of monitoring populations [evaluation of basal cortisol for diagnosis of hypoadrenocorticism](https://pubmed.ncbi.nlm.nih.gov/27714859/). If electrolytes are normal and the dog is otherwise well, consider non-adrenal causes of polyuria, including diabetes mellitus, hyperadrenocorticism, or renal disease. Review the owner's medication administration technique, since missed or erratic glucocorticoid dosing is a common cause of persistent clinical signs. ### What Records Should I Maintain for a Long-Term Addisonian Dog to Support Continuity of Care? Maintain a problem list that includes the date of diagnosis, the confirmatory test results, the current drug formulations and doses, and the date of the most recent dose adjustment. Record every electrolyte panel with the corresponding mineralocorticoid dose and the interval since the last DOCP injection or the daily fludrocortisone dose. Document any crisis events, including triggers, treatments administered, and outcomes. Note the dog's baseline body weight, since dose adjustments are often weight-based and significant weight change may require recalculating the dose. This structured record supports consistent monitoring and reduces the risk of dosing errors when multiple clinicians see the same patient [AVMA practice resources](https://www.avma.org/resources-tools). ## Related Clinical & Scientific Guides * [Feline Hepatic Lipidosis: Nutritional and Medical Management](/knowledge/veterinary-medicine/clinical-internal-medicine/feline-hepatic-lipidosis-nutritional-medical-management) * [Canine Respiratory Infection: Diagnostic Approach and Treatment](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-respiratory-infection-diagnostic-approach-treatment) * [Canine Respiratory Virus: Diagnostic and Management Considerations](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-respiratory-virus-diagnostic-management-considerations) ## References and Further Reading - [Canine hypoadrenocorticism: part I.](https://pubmed.ncbi.nlm.nih.gov/20357943/). 2010. - [Evaluation of Basal Serum or Plasma Cortisol Concentrations for the Diagnosis of Hypoadrenocorticism in Dogs.](https://pubmed.ncbi.nlm.nih.gov/27714859/). 2016. - [Emesis in dogs: a review.](https://pubmed.ncbi.nlm.nih.gov/20137004/). 2010. - [Congenital Portosystemic Shunts in Dogs and Cats: Classification, Pathophysiology, Clinical Presentation and Diagnosis.](https://pubmed.ncbi.nlm.nih.gov/36851464/). 2023. - [ACVIM Consensus Statements](https://www.acvim.org/Animal-Owners/Animal-Education/Consensus-Statements). Journal of Veterinary Internal Medicine. - [MSD Veterinary Manual, Professional Edition](https://www.msdvetmanual.com/). MSD Veterinary Manual. - [American Veterinary Medical Association Practice Resources](https://www.avma.org/resources-tools). American Veterinary Medical Association. - [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/). WOAH. ## Related Articles - [Canine and Feline Chronic Diarrhea: Diagnostic and Therapeutic Framework](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-feline-chronic-diarrhea-diagnostic-therapeutic) - [Canine Gallbladder Disease: Diagnostic and Therapeutic Approach](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-gallbladder-disease-diagnostic-therapeutic-approach) - [Canine Immune-Mediated Myositis: Diagnostic and Therapeutic Approach](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-immune-mediated-myositis-diagnostic-therapeutic-approach) - [Canine Systemic Hypertension: Diagnosis and Therapeutic Monitoring](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-systemic-hypertension-diagnosis-therapeutic-monitoring) - [Canine Inflammatory Bowel Disease: Diagnostic and Therapeutic Approach](/knowledge/veterinary-medicine/clinical-internal-medicine/canine-inflammatory-bowel-disease-diagnostic-therapeutic-approach) > This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.