Telmisartan
**Telmisartan** is an angiotensin II receptor blocker (ARB) primarily used in veterinary medicine for the management of **feline chronic kidney disease (CKD)** to reduce proteinuria, and for the treatment of **systemic hypertension** in cats. It is available as an oral solution that is generally well-tolerated. > **Clinical Warning:** The safety and efficacy of telmisartan for managing systemic hypertension above 200 mmHg has not been investigated. Blood pressure monitoring is highly recommended, especially in cats showing signs of hypotension or those undergoing general anaesthesia. **Clinical Pearl:** Telmisartan appears to be as effective as benazepril at delaying the deterioration of proteinuria over 6 months in cats with IRIS stage IIa to IV CKD.
Mechanism: Telmisartan is a specific **Angiotensin II receptor (type AT1) antagonist**. By blocking this receptor, it inhibits the detrimental effects of angiotensin II, including: * **Vasoconstriction** → lowers systemic blood pressure. * **Aldosterone synthesis** → reduces sodium and water retention. * **Renal, vascular, and cardiac remodelling**. In the kidneys, blocking angiotensin II reduces **glomerular capillary hypertension** and decreases protein in the glomerular filtrate, which helps prevent the triggering or potentiation of interstitial fibrosis.
Dosing by species
- Protein-losing nephropathy and hypertension · 0.5-1 mg/kg · PO · q24h · Limited information; successful case reports exist for use in combination with amlodipine.
- Reduction of proteinuria associated with chronic kidney disease · 1 mg/kg · PO · q24h · Authorized indication. Use 4 mg/ml solution.
- Treatment of systemic hypertension · 2 mg/kg · PO · q24h · Authorized indication. Use 10 mg/ml solution.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Breeding cats
- Pregnant cats
- Lactating cats
- Cats under 6 months of age
Adverse effects
- Regurgitation
- Vomiting
- Diarrhoea
- Increased ALT activity (rare, transient)
- Hypotension
- Decreased RBC count
- Increased BUN
Drug interactions
- Amlodipine · Safe concurrent use for hypertension; no clinical evidence of hypotension at recommended doses. · minor
- ACE inhibitors (e.g., benazepril) · Avoid concurrent use due to potential for excessive hypotension and renal impairment. · major
Monitoring
- Systemic blood pressure
- Urine protein:creatinine ratio (UPC)
- Renal parameters (BUN, creatinine)
- Liver enzymes (ALT)
- Red blood cell count / PCV
Overdose
In healthy cats administered **5 times the recommended dose for 6 months**, observed effects included decreases in blood pressure, decreases in red blood cell (RBC) count, and increases in blood urea nitrogen (BUN).
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.