Telmisartan Hydrochlorothiazide

Telmisartan/hydrochlorothiazide is an antihypertensive combination. Telmisartan antagonizes the effect of angiotensin II (vasoconstriction and aldosterone secretion) by blocking the angiotensin II (ATj receptor) in vascular smooth muscle and the adrenal gland, producing decreased BP. Hydrochlorothiazide (HCTZ) increases chloride, sodium, and water excretion by interfering with transport of sodinm ions across renal tubular epithelium. It is indicated in the treatment of hypertension. 

Symptomatic hypotension may occur when an angiotensin II receptor antagonist is started in patients taking high-dose diuretics. Potassium levels may be either increased, decreased or not affected. No clinically relevant pharmacokinetic interactions appear to occur between candesartan, eprosartan, irbesartan, losartan, telmisartan or valsartan and hydrochlorothiazide, although the bioavailability of hydrochlorothiazide may be modestly reduced. Similarly, there is no clinically significant pharmacokinetic interaction between valsartan and furosemide. 

In a randomised, crossover study in 13 healthy subjects, telmisartan 160 mg daily was given with hydrochlorothiazide 25 mg daily for 7 days. There was no difference in AUC and maximum plasma concentrations of either drug compared with when they were given alone. Similarly, no pharmacokinetic interactions were found between irbesartan and hydrochlorothiazide. ... 

Yoi C-L, Dias VC, Stai ier J. Multiple-dose pharmacokinetics of telmisartan and of hydrochlorothiazide foUowii concurrent administration in healthy subjects. J Clin Pharmacol (2000) 40,1323-30. 

In an open, randomized, crossover trial in 18 patients with chronic non-diabetic proteinuric kidney disease, double blockade with telmisartan and cilazapril plus hydrochlorothiazide was compared with triple blockade (the addition of spironolactone) [32 ]. Plasma renin activity and proteinuria were reduced, but the risk of hyperkalemia increased. 

---