Drug Monograph
Full clinical overview, indications, dosage references & safety notes.
Available forms5 forms · 16 strengths documentedShow all ↓
Tablet 0.25 mgTablet 0.5 mgTablet 0.75 mgTablet 1 mgTablet 1.5 mgTablet 2 mgTablet 4 mgTablet 6 mg
Solution 0.5 mg/5 mLSolution 1 mg/mL Intensol concentrate
Dexamethasone base 2 mg/mL Azium, in PEG — do NOT give rapid IVSodium phosphate 4 mg/mL Hexadrol; ≈ 3 mg/mL baseSodium phosphate 10 mg/mL HexadrolSodium phosphate 20 mg/mL Hexadrol
Solution 0.1% Maxidex, Maxitrol
Suspension 0.9 mg/mL Aurizon (+ clotrimazole + marbofloxacin)
Overview
Dexamethasone (Azium®, Dexasone®) is a potent, long-acting synthetic glucocorticoid used in veterinary medicine to manage inflammation, allergic reactions, immune-mediated diseases, and acute emergency conditions.
It is approximately 30 times more potent than hydrocortisone and 7-7.5 times more potent than prednisolone (0.15 mg dexamethasone ≈ 1 mg prednisolone), with NO mineralocorticoid activity. Because its biological half-life is long (36-48+ hours; effects persist beyond 48 hours), treatment should always use the lowest effective dose. Tapering is required when treatment exceeds 2 weeks to prevent adrenal crisis from HPA-axis suppression.
Mechanism of Action (MOA): Dexamethasone suppresses key inflammatory pathways, reduces cytokine production, and decreases immune-cell activation, leading to a rapid reduction in swelling, redness, and immune-driven tissue damage.
Indications
Dexamethasone is used in dogs and cats when strong and rapid suppression of inflammation or immune activity is required. It is often chosen in acute situations or when other corticosteroids are not effective enough.
- Severe allergic reactions: Useful for acute hypersensitivity, anaphylaxis, post-vaccination reactions, angioedema, and envenomation.
- Inflammatory conditions: Respiratory inflammation (feline asthma-like episodes, bronchitis), dermatologic flare-ups, musculoskeletal inflammation, and gastrointestinal inflammatory episodes such as IBD exacerbations.
- Immune-mediated diseases: Provides fast immunosuppression in IMHA, ITP, autoimmune skin disease, and masticatory myositis.
- Adrenal insufficiency (crisis support): Used during Addisonian crisis because it does not interfere with cortisol testing, making it safe to use before ACTH stimulation tests.
- Neurologic emergencies: CONTROVERSIAL — short-term use to reduce intracranial pressure in select cases. Routine use in spinal cord injury is NO LONGER recommended. dexamethasone has caused fatal colonic perforations in dogs with spinal cord injuries.
high-dose glucocorticoids in neurologic disease may cause excitotoxic cell death. Use only with specialist input and strict GI ulcer prophylaxis.
Dosage (Reference)
Dog
Dexamethasone in dogs is mainly used for short-term control of inflammation, immune-mediated flare-ups, or initial stabilization in adrenal crisis due to its strong and long-lasting glucocorticoid effect.
| Clinical use | Route | Dose (mg/kg) | Frequency | Duration | Notes |
|---|---|---|---|---|---|
| Anti-inflammatory | PO / IM / IV / SC | 0.07–0.14 | q24h | 3–5 days max | Short courses recommended. |
| Immunosuppressive (IMHA / ITP) | IV | 0.2–0.4 | q24h | up to 5 days | When oral meds cannot be given. |
| Addisonian crisis | IV | 0.1–0.2 | q24h | — | Safe before ACTH test. |
| Addisonian crisis (alternative) | IV | 0.2–0.5 | q24h | — | For severe collapse. |
Cat
Cats generally require higher mg/kg doses than dogs and may tolerate short-term therapy well. Monitoring is important due to the risk of steroid-induced hyperglycemia.
| Clinical use | Route | Dose (mg/kg) | Frequency | Duration | Notes |
|---|---|---|---|---|---|
| Anti-inflammatory | PO / IM / IV / SC | 0.14–0.28 | q24h | 3–5 days max | Standard range. |
| Hypersensitivity dermatitis | PO | 0.2 | q24h | — | Rapid symptomatic relief. |
| Addisonian crisis | IV / IM | 0.1–0.2 | q12–24h | — | Initial stabilization. |
Dogs:
• LDDS: 0.01 mg/kg IV (samples at 0, 4, 8 hours)
• HDDS: 0.1 mg/kg IV (used when Cushing’s is already confirmed)
Cats:
• LDDS: 0.1 mg/kg IV
• HDDS: 1 mg/kg IV
These doses are for diagnostic evaluation only and are not used for treatment.
Warnings & Precautions
Because dexamethasone has strong and long-lasting glucocorticoid activity, it must be used carefully in patients with systemic disease, risk of ulcers, impaired immunity, or endocrine disorders.
- Systemic fungal infections: Systemic use is contraindicated unless replacing glucocorticoids in Addisonian patients.
- GI ulceration and perforation: Risk is significantly higher when combined with NSAIDs; avoid concurrent use.
- Diabetes mellitus: May cause substantial hyperglycemia, especially in cats; use cautiously and monitor glucose.
- Active or suspected infection: Can mask fever and clinical signs and suppress immune response; use with caution.
- Renal insufficiency: Patients with reduced renal function are more prone to GI complications.
- Long-term therapy: Treatment beyond 2 weeks suppresses the HPA axis; taper gradually to avoid adrenal crisis.
- Ocular effects: Prolonged use (systemic or ophthalmic) may increase intraocular pressure or contribute to cataracts.
- Cats at risk of diabetes: Extra monitoring required due to the stronger hyperglycemic effect in cats.
- Concurrent infections, ulcers, corneal disease: Use cautiously in animals with ulcers, corneal damage, or bacterial infections.
- Stress or surgery during tapering: Animals tapering off dexamethasone may require supplemental steroids during stress.
- Pregnancy: Pregnancy: Contraindicated unless used intentionally for parturition induction in late-term large-animal pregnancy. Use in pregnant dogs and cats is associated with cleft palate in laboratory animal studies and may induce parturition in late-stage pregnancy.
- Shock and spinal cord injury: Shock and spinal injury: use of long-acting steroids in most cases of shock and spinal injury is of no benefit and may be detrimental. High-dose dexamethasone in dogs with spinal cord injuries has caused fatal colonic perforations. Routine use in these conditions is NO LONGER recommended.
- Comparative GI risk in dogs: Comparative GI risk: In dogs, dexamethasone causes more GI complications and bleeding than prednisone. When an equivalent oral steroid course is feasible, prednisone or prednisolone is preferred. To convert: divide the desired prednisolone dose by 7 to get the dexamethasone dose (1 mg prednisolone ≈ 0.14 mg dexamethasone).
- IV administration: IV administration: The 2 mg/mL dexamethasone solution (e.g., Azium) is in a polyethylene glycol vehicle and must NOT be administered rapidly IV — risk of hypotension, collapse, and hemolytic anemia. For IV use, prefer dexamethasone sodium phosphate (water-soluble, e.g., 4 mg/mL injection equivalent 3 mg/mL dexamethasone base).
Drug Interactions
Only a small number of drug interactions with dexamethasone are clinically relevant in dogs and cats. These are the ones most likely to change the drug’s effect or increase the risk of adverse reactions in everyday practice.
- NSAIDs: Major interaction. Combining NSAIDs with corticosteroids greatly increases the risk of gastrointestinal ulceration and perforation—avoid using them together.
- Insulin: Dexamethasone decreases insulin sensitivity and may increase the required insulin dose, especially in diabetic cats. Monitor blood glucose closely.
- Potassium-depleting diuretics (e.g., furosemide): Higher risk of hypokalemia when used together; electrolyte monitoring is recommended.
- Phenobarbital: May reduce dexamethasone effectiveness by increasing hepatic metabolism.
- Azole antifungals (ketoconazole): Can increase dexamethasone blood levels by slowing its metabolism, potentially prolonging effects.
- Modified-live vaccines: Should be avoided in animals receiving immunosuppressive doses of corticosteroids.
- Fluoroquinolones: Fluoroquinolones (enrofloxacin, marbofloxacin): Concurrent use with glucocorticoids increases the risk of tendon rupture.
- Amphotericin B: Amphotericin B: Concurrent use with glucocorticoids may cause hypokalemia. Monitor electrolytes closely if treating systemic fungal infection in a steroid-dependent patient.
- Anticholinesterases (myasthenia gravis): Anticholinesterase agents (pyridostigmine, neostigmine) in myasthenia gravis patients: Concomitant glucocorticoid use may lead to profound muscle weakness. If possible, discontinue anticholinesterase medication at least 24 hours prior to glucocorticoid administration.
Side Effects & Overdose
Side Effects
Most adverse effects appear with repeated or high-dose use, especially in dogs. Cats are generally more tolerant but still require monitoring.
- PU/PD/PP: Very common in dogs during therapy.
- Muscle wasting & weight gain: With prolonged use.
- Delayed wound healing: Due to immune and fibroblast suppression.
- GI irritation / ulcers: Risk increases if combined with NSAIDs.
- Behavior changes: Restlessness, panting, or lethargy (dogs).
- Hyperglycemia: More prominent in cats; monitor diabetic patients.
- Elevated liver enzymes: Glucocorticoids increased liver enzyme activities,
- Decreased T4 / thyroid suppression: Decreased serum T4 values: Glucocorticoids can suppress thyroid-stimulating hormone (TSH) and reduce T3 and T4 levels. Avoid interpreting thyroid panels on patients receiving systemic dexamethasone — recheck after discontinuation.
Overdose
Acute overdose is uncommon but can cause serious gastrointestinal and metabolic complications. Chronic high dosing can mimic severe Cushingoid effects.
- Severe GI bleeding: Hematemesis, melena, abdominal pain.
- Electrolyte disturbances: Mainly hypokalemia.
- Shock or collapse: In cases of massive overdose with GI perforation.
- Management: Aggressive IV fluids, GI protectants, electrolyte correction, and stopping the steroid.
Key Notes
Important points to keep in mind when using dexamethasone in dogs and cats, especially during longer treatment courses or when managing unstable patients:
- Use the lowest effective dose: Dexamethasone has a long biological effect; even small doses can suppress the HPA axis for more than 48 hours.
- Avoid sudden withdrawal: Taper slowly if treatment lasted more than 10–14 days to prevent adrenal suppression and crisis.
- Higher diabetes risk in cats: Cats are more prone to steroid-induced hyperglycemia—monitor glucose closely, especially in overweight or pre-diabetic cats.
- GI complications occur more often in dogs: Dogs are more sensitive to steroid-induced GI ulceration and bleeding; monitor for vomiting, melena, anorexia.
- Do not combine with NSAIDs: The risk of GI perforation increases dramatically when NSAIDs and dexamethasone are used together.
- Monitor electrolytes when combined with diuretics: Hypokalemia may develop, particularly when used with furosemide.
- Be cautious in animals with infections: Dexamethasone can mask clinical signs and reduce immune response—use only when necessary and with proper antimicrobial cover.
- In Addisonian crisis: Dexamethasone is preferred before an ACTH stimulation test because it does not interfere with cortisol measurements.
- Long-term use may cause Cushingoid changes: Muscle wasting, coat changes, potbelly appearance, and behavior changes—mainly in dogs.
- Avoid modified-live vaccines: Especially in patients receiving immunosuppressive doses.
