Telmisartan (Semintra, POM-V) is the first veterinary angiotensin-II receptor blocker* to be licensed in the UK. It is licensed for reducing proteinuria associated with chronic kidney disease (CKD) in cats. (SPC 2013) It is advertised as “an easy-to-give, liquid treatment". (Vet Times Advert 2015) How effective is telmisartan? And how does it compare with benazepril, which is licensed for the same indication?
*Angiotensin-II blockers are also known as ARBs, angiotensin-II antagonists or sartans.
Up to 20% of all cats have CKD. (Boyd et al 2010)
Up to 31% of cats aged over 15 years have CKD. (Boyd et al 2010)
The clinical signs of CKD in cats include lethargy, decreased appetite, weight loss, and polyuria and polydipsia. (DiBartola et al 1987)
- In cats, proteinuria is negatively predictive of survival: the hazard ratio for death or euthanasia is 2.9 for a urine protein:creatinine ratio (UPC) of 0.2–0.4 and is 4.0 for UPCs above 0.4, compared to UPCs below 0.2. (Syme 2006)
- Benazepril, an ACE inhibitor, is licensed for reduction of proteinuria in cats with CKD. In double-blind randomised-controlled trials in cats with CKD, treatment with benazepril reduced proteinuria compared with placebo but did not increase survival. (Mizutani et al 2006; King et al 2006)
Result: Telmisartan was judged non-inferior to benazepril in controlling proteinuria. This was on the basis that the difference between telmisartan and benazepril in their effects on UPC was 0.116 (95% confidence interval [CI] -0.035 to 0.268) and the lower confidence limit for this difference (-0.035) was not more negative than the pre-defined non-inferiority margin (-0.108). Both telmisartan and benazepril were well tolerated.
This trial was a non-inferiority trial. Click here to read about this trial design
Pregnancy: pregnant women (vets and owners) should take special care to avoid contact with telmisartan because substances acting on the renin-angiotensin-aldosterone system, such as angiotensin-II receptor blockers, have been found to affect foetuses during pregnancy in humans. (SPC 2013)
Pregnant or lactating cats: Telmisartan should not be used in pregnant or lactating cats. (SPC 2013)
Young cats: The safety and efficacy of telmisartan has not been tested in cats under 6 months of age. (SPC 2013)
During anaesthesia: It is good clinical practice to monitor the blood pressure of cats having telmisartan when under anaesthesia because transient hypotension may occur. (SPC 2013) Symptomatic treatment, such as fluid therapy, should be given when there are any clinical signs of hypotension. (SPC 2013)
- Mild and transient gastrointestinal signs (mild and intermittent regurgitation, vomiting, diarrhoea or soft faeces) occur rarely (in 1–10 in 10,000 cats). (SPC 2013)
- Raised liver enzymes occur very rarely (<1 in 10,000 cats); values normalised within a few days of stopping treatment. (SPC 2013)
- Telmisartan causes a slight decrease in red blood cell count, so this should be monitored during therapy. (SPC 2013)
- In clinical field trials in cats, telmisartan did not affect potassium excretion. (SPC 2013)
To report adverse drug effects go to https://www.vmd.defra.gov.uk/adversereactionreporting/
- The summary of product characteristics (SPC) reports that when telmisartan was used concomitantly with amlodipine at the recommended dose there was no clinical evidence of hypotension. (SPC 2013)
- Although not mentioned in the SPC, there seems to be a potential for interaction with benazepril and other ACE inihibitors. We have received an anecdotal account of hyperkalaemia when telmisartan was used with high doses of benazepril. In humans, hyperkalaemia is a well-recognised risk of using an angiotensin-II receptor blocker and an ACE inhibitor together. (MHRA 2014)
Cost: The list price of telmisartan (4mg/ml) is £16.63 for 30ml. The mean weight of the cats in the trial was about 4kg (Sent 2015); one bottle of telmisartan would last about a month for a 4kg cat. This compares with around £11-13 for benazepril 2.5mg daily (for the brand Fortekor). Cheaper generic versions of benazepril are available.
Telmisartan is an angiotensin-II receptor blocker licensed for reducing proteinuria in cats with chronic kidney disease. There is one published trial of telmisartan in cats, and this formed the basis of the marketing authorisation for the drug. The trial, in cats mainly with borderline proteinuria, showed that telmisartan was no worse than benazepril in reducing proteinuria. Telmisartan gives the option of a treatment in a liquid rather than a tablet form. List prices indicate it costs about the same as benazepril (as Fortekor).
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Goal of activity: Update knowledge; help clinical decision-making
Authors/disclosures: Veterinary Prescriber editorial team/no conflict of interest
Specific learning objectives: to improve knowledge and understanding of the use of telmisartan for cats with CKD.
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Boehringer Ingelheim. Semintra advertisement. Vet Times September 2015.
DiBartola SP et al. Clinicopathologic findings associated with chronic renal disease in cats: 74 cases (1973-1984). JAVMA 1987; 190: 1196-202.
International Renal Interest Society. IRIS Guidelines [online].
MHRA. Combination use of medicines from different classes of renin-angiotensin system blocking agents: risk of hyperkalaemia, hypotension, and impaired renal function—new warnings. Drug Safety Update 2014.