Chlorothiazide
Chlorothiazide / Chlorothiazide Sodium
Also known as: Diuril · Azide · Chlorzide · Chlotride · Diachlor · Diurigen · Pahtlisan · Saluric · chlorothiazidum · clorotiazida
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of nephrogenic diabetes insipidus | 20-40 mg/kg | PO | q12h | — | 🌎 NA |
| Treatment of systemic hypertension | 20-40 mg/kg | PO | q12-24h | — | 🌎 NA |
| As a diuretic | 20-40 mg/kg | PO | q12h | — | 🌎 NA |
- Treatment of systemic hypertension: Use with dietary salt restriction
- As a diuretic: Twice daily
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of diabetes insipidus | 20-40 mg/kg | PO | q12h | — | 🌎 NA |
| As a diuretic | 20-40 mg/kg | PO | q12h | — | 🌎 NA |
- Treatment of diabetes insipidus: May be tried
- As a diuretic: Twice daily
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| General dosing for adult cattle | 4-8 mg/kg | PO | once or twice daily | — | 🌎 NA |
| General dosing | 2 g | PO | once to twice daily | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Chlorothiazide is a thiazide diuretic primarily used in veterinary medicine for the management of nephrogenic diabetes insipidus, systemic hypertension, and the prevention of calcium oxalate urolithiasis in dogs.
While largely replaced by loop diuretics (like furosemide) for the treatment of general edema, it remains a crucial targeted therapy.
Clinical Pearl: Thiazides paradoxically reduce urine output in patients with diabetes insipidus. They induce a mild state of volume depletion, which leads to a compensatory increase in the reabsorption of sodium and water in the proximal tubule, ultimately decreasing the volume of filtrate delivered to the distal nephron.
Mechanism of action
Chlorothiazide acts primarily on the distal convoluted tubule (DCT) of the nephron.
- Primary Mechanism: Inhibits the Na⁺/Cl⁻ symporter in the luminal membrane of the DCT → prevents reabsorption of sodium and chloride → promotes osmotic diuresis.
- Electrolyte Effects: Enhances excretion of sodium, chloride, potassium, magnesium, phosphate, iodide, and bromide.
- Calcium Sparing: Unlike loop diuretics, thiazides decrease urinary calcium excretion with chronic use, making them useful for preventing calcium oxalate uroliths.
- Hemodynamic Effects: Decreases glomerular filtration rate (GFR). The resulting volume depletion activates the renin-angiotensin-aldosterone system (RAAS), which contributes to downstream potassium wasting (hypokalemia).
Safety & warnings
Contraindications
- Hypersensitivity to thiazides or sulfonamides
- Anuria
- Pregnancy in otherwise healthy females with only mild edema (relative contraindication)
Adverse effects
- Hypokalemia
- Hypochloremic alkalosis
- Dilutional hyponatremia
- Hypomagnesemia
- Hypercalcemia
- Hypophosphatemia
- Hyperuricemia
- Gastrointestinal distress (vomiting, diarrhea)
- Pancreatitis
- Hypersensitivity / dermatologic reactions
- Polyuria
- Hematologic toxicity
- Hyperglycemia
- Hyperlipidemias
- Orthostatic hypotension
Precautions
Use with extreme caution or avoid in patients with severe renal disease, preexisting electrolyte or water balance abnormalities, impaired hepatic function (may precipitate hepatic coma), hyperuricemia, systemic lupus erythematosus (SLE), or diabetes mellitus. Monitor patients with conditions that may lead to fluid/electrolyte loss (e.g., vomiting, diarrhea) very carefully.
Drug interactions
Increased risk for severe hypokalemia
Increased risk for severe hypokalemia
Increased risk for hyperglycemia, hyperuricemia, and hypotension
Thiazide-induced hypokalemia, hypomagnesemia, and/or hypercalcemia may increase the likelihood of digitalis toxicity
Thiazides may increase insulin requirements
Thiazides can increase serum lithium concentrations
Thiazides can alkalinize urine and reduce methenamine effectiveness
May increase risk for renal toxicity; NSAIDs may reduce diuretic actions of thiazides
Response or duration of nondepolarizing agents (e.g., tubocurarine) may be increased
Blocks thiazide-induced uric acid retention
Half-life may be prolonged by thiazides due to urine alkalinization
Hypercalcemia may be exacerbated
Monitoring
- Serum electrolytes (especially potassium)
- BUN and Creatinine
- Blood glucose
- Hydration status
- Blood pressure (if indicated)
- Hemograms (if indicated)
Pharmacokinetics
Absorption
In humans, only 10-21% absorbed after oral administration. Onset of diuretic activity occurs in 1-2 hours and peaks at about 4 hours.
Distribution
Enters maternal milk.
Metabolism
Pharmacokinetics have apparently not been studied in domestic animals.
Elimination
Duration of activity is from 6-12 hours (in humans).
Overdose
Acute overdosage may cause electrolyte and water balance problems, CNS effects (ranging from lethargy to coma and seizures), and GI effects (hypermotility, GI distress). Transient increases in BUN have also been reported.
Treatment:
- Empty the gut after recent oral ingestion using standard protocols.
- Avoid concomitant cathartics as they may exacerbate fluid and electrolyte imbalances.
- Monitor and treat electrolyte and water balance abnormalities supportively.
- Monitor respiratory, CNS, and cardiovascular status; provide symptomatic and supportive care as required.
Available products
Formulations
- Tablets
- Oral suspension
- Powder for injection (lyophilized)
Human-labeled
- Chlorothiazide Tablets: 250 mg & 500 mg (Diuril®, Diurigen®, generic)
- Chlorothiazide Oral Suspension: 50 mg/mL in 237 mL (Diuril®)
- Chlorothiazide Sodium Powder for Injection (lyophilized): 500 mg in 20 mL vials (Diuril®)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Tablets should be stored at room temperature. The oral suspension should be protected from freezing. The injectable preparation is stable for 24 hours after reconstitution. If the pH of the reconstituted solution is less than 7.4, precipitation will occur in less than 24 hours.
Client information
- Water Access: Ensure your pet always has access to fresh drinking water unless specifically instructed otherwise by your veterinarian.
- Monitor for Dehydration/Imbalance: Contact your veterinarian immediately if you notice signs of water or electrolyte imbalance, such as excessive thirst, severe lethargy, weakness, restlessness, reduced urination, vomiting, diarrhea, or a rapid heart rate.
- Administration: Can be given with food if it causes stomach upset.
- Consistency: Do not stop giving this medication abruptly without consulting your veterinarian, especially if it is being used to manage blood pressure or diabetes insipidus.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.