Tekturna HCT 300mg/12.5mg Tablet
Actual product appearance may differ slightly.
Tekturna HCT is a combination of aliskiren, a direct renin inhibitor, and hydrochlorothiazide, a thiazide diuretic, and is indicated for the treatment of hypertension.
Actions: Aliskiren; Hydrochlorothiazide combines two antihypertensive agents with different mechanisms to lower blood pressure; the effects of aliskiren and hydrochlorothiazide on blood pressure are additive. Aliskiren is the first approved renin inhibitor and acts within the renin-angiotensin-aldosterone system (RAAS), a hormone system important in the regulation of blood pressure, electrolyte homeostasis, and vascular growth. The RAAS includes a cascade of events, beginning with renin, which cleaves the inactive peptide angiotensinogen, converting it to angiotensin I. Angiotensin I (Ang I) is then converted by angiotensin-converting enzyme (ACE) to the biologically active vasoconstrictor angiotensin II (Ang II). Aliskiren decreases plasma renin activity and inhibits the conversion of angiotensinogen to Ang I. Whether aliskiren affects other RAAS components (e.g., ACE or non-ACE pathways) is not known. Thiazide diuretics increase the excretion of sodium, chloride, and water by inhibiting sodium ion transport across the renal tubular epithelium. Although thiazides may have more than one action, the major mechanism responsible for diuresis is to inhibit active chloride reabsorption at the distal portion of the ascending limb or, more likely, the early part of the distal tubule (i.e., the cortical diluting segment). The antihypertensive mechanism of hydrochlorothiazide is unknown. Initially, diuretics lower blood pressure by decreasing cardiac output and reducing plasma and extracellular fluid volume. Cardiac output eventually returns to normal, plasma and extracellular fluid values return to slightly less than normal, but peripheral vascular resistance is reduced, resulting in lower blood pressure. Hydrochlorothiazide also decreases the glomerular filtration rate, which contributes to the lower efficacy seen in patients with renal impairment. The changes in plasma volume induce an elevation in plasma renin activity, and aldosterone secretion is increased, contributing to the potassium loss associated with thiazide diuretic therapy. In general, diuretics worsen LVH and glucose tolerance, and exert detrimental effects on the lipid profile.
Uses: Aliskiren; Hydrochlorothiazide is indicated for the treatment of hypertension. The fixed-dose combination is not indicated for initial therapy; however, it may be substituted for the titrated individual components. A patient whose blood pressure is not adequately controlled with aliskiren or hydrochlorothiazide alone may be switched to the combination product. A patient whose blood pressure is controlled with hydrochlorothiazide alone but who experiences hypokalemia may be switched to the combination product. A patient who experiences dose-limiting adverse reactions on either component alone may be switched to the combination product at a lower dose of that component in combination with the other to achieve similar blood pressure reductions.
Drug Interactions: Drugs known to alter the pharmacokinetics of aliskiren include ketoconazole, irbesartan, and atorvastatin. The pharmacokinetics of furosemide are altered when coadministered with aliskiren. Drugs known to interact with hydrochlorothiazide include alcohol, barbiturates, narcotics, antidiabetic agents, antihypertensive agents, cholestyramine, colestipol, corticosteroids, ACTH, pressor amines (e.g., norepinephrine), nondepolarizing skeletal muscle relaxants, lithium, and NSAIDs.
Major Adverse Effects: The most common adverse effects that occurred in patients treated with aliskiren; hydrochlorothiazide at a higher incidence than placebo included dizziness (2.3% vs. 1%), influenza (2.3% vs. 1.6%), diarrhea (1.6% vs. 0.5%), cough (1.3% vs. 0.5%), vertigo (1.2% vs. 0.5%), asthenia (1.2% vs. 0%), and arthralgia (1% vs. 0.5%).