Hydrocortisone

Hydrocortisone is cortisol supplied medicinally and has both glucocorticoid and mineralocorticoid activity. Its major systemic veterinary role is adrenal hormone replacement, particularly when rapid parenteral treatment is required. Topical formulations have a separate role in localized inflammatory skin disease. Its activity profile resembles endogenous cortisol more closely than that of more potent synthetic glucocorticoids.

Group

Glucocorticoid

Mechanism of Action

Hydrocortisone binds intracellular glucocorticoid receptors and alters transcription of genes controlling metabolism, inflammatory signaling and immune-cell function. Replacement restores deficient cortisol-dependent responses, while pharmacologic exposure suppresses inflammation. It also activates mineralocorticoid pathways that influence renal sodium and potassium handling. Soluble sodium succinate formulations release hydrocortisone for systemic activity, while topical preparations act primarily at treated skin sites.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Adrenal replacement	1–2 mg/kg	PO	Every 12 h
Anti-inflammatory treatment	2.5–5 mg/kg	PO	Every 12 h
Adrenal crisis	0.625 mg/kg/hour	IV	Continuous	Hydrocortisone sodium succinate; monitor sodium, potassium, glucose and circulation.
Anti-inflammatory treatment	5 mg/kg	IV	Every 12 h	Sodium succinate formulation.
Historical shock regimen	Reference only	IV		Not a recommended use: sodium succinate 50-150 mg/kg for two doses 8 hours apart. Retained for clinical context, not routine shock treatment.
Adrenal replacement	1 mg/kg	PO	Every 24 h	Separate general starting daily replacement recommendation; the detailed oral dosage section gives a higher every-12-hour alternative. Titrate according to endocrine assessment.
Adrenal crisis	0.5 mg/kg/hour	IV	Continuous	Sodium succinate; continue until oral intake and GI function permit oral replacement.
Adrenal crisis intermittent treatment	2 mg/kg	IV	Every 6 h	Sodium succinate alternative.
Adrenal crisis intermittent treatment	2–4 mg/kg	IV	Every 8 h	Separate sodium succinate alternative.
Low-dose septic-shock adjunct	0.08 mg/kg/hour	IV	Continuous	Low-dose adjunct protocol, distinct from historical high-dose shock treatment.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Adrenal replacement	1–2 mg/kg	PO	Every 12 h
Anti-inflammatory treatment	2.5–5 mg/kg	PO	Every 12 h
Adrenal crisis	0.625 mg/kg/hour	IV	Continuous	Hydrocortisone sodium succinate; monitor sodium, potassium, glucose and circulation.
Anti-inflammatory treatment	5 mg/kg	IV	Every 12 h	Sodium succinate formulation.
Historical shock regimen	Reference only	IV		Not a recommended use: sodium succinate 50-150 mg/kg for two doses 8 hours apart. Retained for clinical context, not routine shock treatment.
Adrenal replacement	1 mg/kg	PO	Every 24 h	Separate general starting daily replacement recommendation; the detailed oral dosage section gives a higher every-12-hour alternative. Titrate according to endocrine assessment.
Low-dose septic-shock adjunct	0.08 mg/kg/hour	IV	Continuous	Low-dose adjunct protocol, distinct from historical high-dose shock treatment.

Horses

Use / stage	Dose	Route	Schedule	Instructions
Anti-inflammatory treatment	5 mg/kg	IV	Every 12 h	Sodium succinate formulation.
Critical-illness adrenal replacement	1–3 mg/kg	IV	Every 24 h	Foals only; total daily amount, with delivery individualized.
Glucocorticoid therapy	1–4 mg/kg	IV		Sodium succinate by infusion; duration and repeat schedule are not specified.

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Photosensitization adjunct	Reference only	IV		100-600 mg/animal in 1 L of 10% dextrose-saline; salt is not specified, so concentration conversion is not assigned.
Photosensitization adjunct	Reference only	SC		100-600 mg/animal in 1 L of 10% dextrose-saline; salt unspecified.

Indications

Glucocorticoid replacement in dogs, cats and other veterinary patients with adrenal insufficiency.
Parenteral treatment of acute adrenal insufficiency or an Addisonian crisis within a complete emergency treatment plan.
Treatment of selected inflammatory or immune-mediated disorders when hydrocortisone is the chosen systemic glucocorticoid.
Local treatment of selected inflammatory or pruritic skin disease with an appropriate topical preparation.
Specialist adjunctive treatment of selected vasopressor-refractory shock with suspected inadequate corticosteroid activity; veterinary outcome evidence is limited.

Contraindications

Use cautiously with diabetes, active infection, gastrointestinal ulceration, impaired wound healing or pregnancy.

Interactions

NSAIDs increase gastrointestinal ulceration and bleeding.
May antagonize insulin and impair glycaemic control.

Adverse effects

Polyphagia, polydipsia and polyuria
Adrenal suppression, hyperglycaemia, hepatopathy and secondary infection
Delayed wound healing

Toxicity

Excessive exposure causes iatrogenic hyperadrenocorticism and immunosuppression; abrupt withdrawal after prolonged treatment may cause adrenal insufficiency.

Preparations

Preparation	Form	Strength	Route
Hydrocortisone 5 mg tablet	Tablet	5 mg / tablet	PO
Hydrocortisone 10 mg tablet	Tablet	10 mg / tablet	PO
Hydrocortisone 20 mg tablet	Tablet	20 mg / tablet	PO
Hydrocortisone sodium succinate 100 mg vial Vial presentation; no unverified final mL concentration. Check the labelled hydrocortisone-equivalent basis before substitution.	Injection	100 mg / vial	IV, IM
Hydrocortisone sodium succinate 250 mg vial Vial presentation; no unverified final mL concentration. Check the labelled hydrocortisone-equivalent basis before substitution.	Injection	250 mg / vial	IV, IM
Hydrocortisone sodium succinate 500 mg vial Vial presentation; no unverified final mL concentration. Check the labelled hydrocortisone-equivalent basis before substitution.	Injection	500 mg / vial	IV, IM
Hydrocortisone sodium succinate 1000 mg vial Vial presentation; no unverified final mL concentration. Check the labelled hydrocortisone-equivalent basis before substitution.	Injection	1000 mg / vial	IV, IM

Monitoring and Administration

Monitor glucose, hepatic and renal parameters, infection and adrenal function when indicated.

Taper sustained systemic treatment according to response rather than stopping abruptly; depot injections cannot be withdrawn after administration.

A separate general replacement statement gives 1 mg/kg/day, whereas the oral dosage section gives 1-2 mg/kg every 12 hours. These are distinct reported guidance recommendations; choose replacement intensity from the clinical endocrine assessment.

Hydrocortisone degrades at alkaline pH above approximately 7-9. Specific compounded suspensions, ointments and lotions were stable for 30 days; this does not establish stability of every vehicle.

The 0.3 mg/kg acute-crisis CRI statement omits a time denominator and cannot establish an infusion rate. Reconstituted sodium-succinate solutions must be clear, protected from light and used within the particular product’s stated period; a three-day period is described for the listed presentations. Do not autoclave.

Topical hydrocortisone is applied sparingly 1-4 times daily initially, then tapered to the smallest area and shortest course needed; focal courses are generally under 2 months. Shampoo contact is at least 10 minutes before rinsing. Prevent licking for 20-30 minutes; prolonged frequent use can cause skin atrophy and HPA suppression. A two-week interruption before allergy testing is described. Cream/ointment strengths 0.5%, 1% and 2.5%, plus multi-active veterinary products, require the actual product concentration basis before mass conversion.