Micardis Hct Information
Micardis hct (Telmisartan,hydrochlorothiazide)
Micardis hct (Telmisartan,hydrochlorothiazide) Description
Micardis hct (Telmisartan,hydrochlorothiazide) tablets are a combination of telmisartan, an orally active angiotensin II antagonist acting on the AT receptor subtype, and hydrochlorothiazide, a diuretic.
Telmisartan, a non-peptide molecule, is chemically described as 4'-[(1,4'-dimethyl-2'-propyl[2,6'-bi-1H-benzimidazol]-1'-yl)methyl]-[1,1'-biphenyl]-2-carboxylic acid. Its empirical formula is CHNO, its molecular weight is 514.63, and its structural formula is:
Telmisartan is a white to slightly yellowish solid. It is practically insoluble in water and in the pH range of 3 to 9, sparingly soluble in strong acid (except insoluble in hydrochloric acid), and soluble in strong base.
Hydrochlorothiazide is a white, or practically white, practically odorless, crystalline powder with a molecular weight of 297.74. It is slightly soluble in water, and freely soluble in sodium hydroxide solution. Hydrochlorothiazide is chemically described as 6-chloro-3,4-dihydro-2-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its empirical formula is CHClNOS, and its structural formula is:
Micardis hct (Telmisartan,hydrochlorothiazide) tablets are formulated for oral administration in three combinations of 40 mg/12.5 mg, 80 mg/12.5 mg, and 80 mg/25 mg telmisartan and hydrochlorothiazide, respectively. The tablets contain the following inactive ingredients: sodium hydroxide, meglumine, povidone, sorbitol, magnesium stearate, lactose monohydrate, microcrystalline cellulose, maize starch, sodium starch glycolate. As coloring agents, the 40 mg/12.5 mg and 80 mg/12.5 mg tablets contain ferric oxide red, and the 80 mg/25 mg tablets contain ferric oxide yellow. Micardis® HCT (telmisartan and hydrochlorothiazide) tablets are hygroscopic and require protection from moisture.
Micardis hct (Telmisartan,hydrochlorothiazide) Clinical Pharmacology
Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. Telmisartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT receptor in many tissues, such as vascular smooth muscle and the adrenal gland. Its action is therefore independent of the pathways for angiotensin II synthesis.
There is also an AT receptor found in many tissues, but AT is not known to be associated with cardiovascular homeostasis. Telmisartan has much greater affinity (>3,000 fold) for the AT receptor than for the AT receptor.
Blockade of the renin-angiotensin system with ACE inhibitors, which inhibit the biosynthesis of angiotensin II from angiotensin I, is widely used in the treatment of hypertension. ACE inhibitors also inhibit the degradation of bradykinin, a reaction also catalyzed by ACE. Because telmisartan does not inhibit ACE (kininase II), it does not affect the response to bradykinin. Whether this difference has clinical relevance is not yet known. Telmisartan does not bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation.
Blockade of the angiotensin II receptor inhibits the negative regulatory feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and angiotensin II circulating levels do not overcome the effect of telmisartan on blood pressure.
Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly increasing excretion of sodium salt and chloride in approximately equivalent amounts. Indirectly, the diuretic action of hydrochlorothiazide reduces plasma volume, with consequent increases in plasma renin activity, increases in aldosterone secretion, increases in urinary potassium loss, and decreases in serum potassium. The renin-aldosterone link is mediated by angiotensin II, so coadministration of an angiotensin II receptor antagonist tends to reverse the potassium loss associated with these diuretics.
The mechanism of the antihypertensive effect of thiazides is not fully understood.
Micardis hct (Telmisartan,hydrochlorothiazide) Indications And Usage
Micardis® HCT (telmisartan and hydrochlorothiazide) tablets are indicated for the treatment of hypertension. This fixed dose combination is not indicated for initial therapy (see ).
Micardis hct (Telmisartan,hydrochlorothiazide) Contraindications
Micardis hct (Telmisartan,hydrochlorothiazide) tablets are contraindicated in patients with known hypersensitivity (e.g., anaphylaxis or angioedema) to telmisartan, hydrochlorothiazide, or any other component of this product (see ).
Because of the hydrochlorothiazide component, this product is contraindicated in patients with anuria or hypersensitivity to other sulfonamide-derived drugs.
Micardis hct (Telmisartan,hydrochlorothiazide) Warnings
Drugs that act directly on the renin-angiotensin system can cause fetal and neonatal morbidity and death when administered to pregnant women. Several dozen cases have been reported in the world literature in patients who were taking angiotensin converting enzyme inhibitors. When pregnancy is detected, Micardis hct (Telmisartan,hydrochlorothiazide) tablets should be discontinued as soon as possible.
The use of drugs that act directly on the renin-angiotensin system during the second and third trimesters of pregnancy has been associated with fetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure, and death. Oligohydramnios has also been reported, presumably resulting from decreased fetal renal function; oligohydramnios in this setting has been associated with fetal limb contractures, craniofacial deformation, and hypoplastic lung development. Prematurity, intrauterine growth retardation, and patent ductus arteriosus have also been reported, although it is not clear whether these occurrences were due to exposure to the drug.
These adverse effects do not appear to have resulted from intrauterine drug exposure that has been limited to the first trimester. Mothers whose embryos and fetuses are exposed to an angiotensin II receptor antagonist only during the first trimester should be so informed. Nonetheless, when patients become pregnant, physicians should have the patient discontinue the use of Micardis hct (Telmisartan,hydrochlorothiazide) tablets as soon as possible.
Rarely (probably less often than once in every thousand pregnancies), no alternative to an angiotensin II receptor antagonist will be found. In these rare cases, the mothers should be apprised of the potential hazards to their fetuses, and serial ultrasound examinations should be performed to assess the intra-amniotic environment.
If oligohydramnios is observed, Micardis hct (Telmisartan,hydrochlorothiazide) tablets should be discontinued unless they are considered life-saving for the mother. Contraction stress testing (CST), a non-stress test (NST), or biophysical profiling (BPP) may be appropriate, depending upon the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury.
Infants with histories of exposure to an angiotensin II receptor antagonist should be closely observed for hypotension, oliguria, and hyperkalemia. If oliguria occurs, attention should be directed toward support of blood pressure and renal perfusion. Exchange transfusion or dialysis may be required as a means of reversing hypotension and/or substituting for disordered renal function.
A developmental toxicity study was performed in rats with telmisartan/hydrochlorothiazide doses of 3.2/1.0, 15/4.7, 50/15.6, and 0/15.6 mg/kg/day. Although the two higher dose combinations appeared to be more toxic (significant decrease in body weight gain) to the dams than either drug alone, there did not appear to be an increase in toxicity to the developing embryos.
No teratogenic effects were observed when telmisartan was administered to pregnant rats at oral doses of up to 50 mg/kg/day and to pregnant rabbits at oral doses up to 45 mg/kg/day. In rabbits, embryolethality associated with maternal toxicity (reduced body weight gain and food consumption) was observed at 45 mg/kg/day [about 12 times the maximum recommended human dose (MRHD) of 80 mg on a mg/m basis]. In rats, maternally toxic (reduction in body weight gain and food consumption) telmisartan doses of 15 mg/kg/day (about 1.9 times the MRHD on a mg/m basis), administered during late gestation and lactation, were observed to produce adverse effects in neonates, including reduced viability, low birth weight, delayed maturation, and decreased weight gain. Telmisartan has been shown to be present in rat fetuses during late gestation and in rat milk. The no observed effect doses for developmental toxicity in rats and rabbits, 5 and 15 mg/kg/day, respectively, are about 0.64 and 3.7 times, on a mg/m basis, the maximum recommended human dose of telmisartan (80 mg/day).
Studies in which hydrochlorothiazide was administered to pregnant mice and rats during their respective periods of major organogenesis at doses up to 3000 and 1000 mg/kg/day, respectively, provided no evidence of harm to the fetus.
Thiazides cross the placental barrier and appear in cord blood. There is a risk of fetal or neonatal jaundice, thrombocytopenia, and possibly other adverse reactions that have occurred in adults.
Micardis hct (Telmisartan,hydrochlorothiazide) Adverse Reactions
Micardis® HCT (telmisartan and hydrochlorothiazide) tablets has been evaluated for safety in over 1700 patients, including 716 treated for over six months and 420 for over one year. In clinical trials with Micardis hct (Telmisartan,hydrochlorothiazide) tablets, no unexpected adverse events have been observed. Adverse experiences have been limited to those that have been previously reported with telmisartan and/or hydrochlorothiazide. The overall incidence of adverse experiences reported with the combination was comparable to placebo. Most adverse experiences were mild in intensity and transient in nature and did not require discontinuation of therapy.
Adverse events occurring at an incidence of 2% or more in patients treated with telmisartan/hydrochlorothiazide and at a greater rate than in patients treated with placebo, irrespective of their causal association, are presented in .
The following adverse events were reported at a rate less than 2% in patients treated with telmisartan/hydrochlorothiazide and at a greater rate than in patients treated with placebo: back pain, dyspepsia, vomiting, tachycardia, hypokalemia, bronchitis, pharyngitis, rash, hypotension postural, abdominal pain.
Finally, the following adverse events were reported at a rate of 2% or greater in patients treated with telmisartan/hydrochlorothiazide, but were as, or more common in the placebo group: pain, headache, cough, urinary tract infection.
Adverse events occurred at approximately the same rates in men and women, older and younger patients, and black and non-black patients.
In controlled trials (n=1017), 0.3% of patients treated with Micardis® HCT (telmisartan and hydrochlorothiazide) tablets 40/12.5 mg, 80/12.5 mg or 80/25 mg discontinued due to orthostatic hypotension, and the incidence of dizziness was 4%, 7%, and 1%, respectively.
Micardis hct (Telmisartan,hydrochlorothiazide) Dosage And Administration
The usual starting dose of telmisartan is 40 mg once a day; blood pressure response is dose related over the range of 20-80 mg. Patients with depletion of intravascular volume should have the condition corrected or telmisartan tablets should be initiated under close medical supervision (see ). Patients with biliary obstructive disorders or hepatic insufficiency should have treatment started under close medical supervision (see ).
Hydrochlorothiazide is effective in doses of 12.5 mg to 50 mg once daily.
To minimize dose-independent side effects, it is usually appropriate to begin combination therapy only after a patient has failed to achieve the desired effect with monotherapy. The side effects (see ) of telmisartan are generally rare and apparently independent of dose; those of hydrochlorothiazide are a mixture of dose-dependent phenomena (primarily hypokalemia) and dose-independent phenomena (e.g., pancreatitis), the former much more common than the latter. Therapy with any combination of telmisartan and hydrochlorothiazide will be associated with both sets of dose-independent side effects.
Micardis® HCT (telmisartan and hydrochlorothiazide) tablets may be administered with other antihypertensive agents.
Micardis hct (Telmisartan,hydrochlorothiazide) tablets may be administered with or without food.
Micardis hct (Telmisartan,hydrochlorothiazide) How Supplied
Micardis hct (Telmisartan,hydrochlorothiazide) tablets are available in three strengths as biconvex two-layered, oblong-shaped, uncoated tablets in three combinations of 40 mg/12.5 mg, 80 mg/12.5 mg and 80 mg/25 mg telmisartan and hydrochlorothiazide, respectively. The hydrochlorothiazide layer is red in the 40 mg/12.5 mg and 80 mg/12.5 mg tablets, and yellow in the 80 mg/25 mg tablets, and all are unmarked. The telmisartan layer for all three strengths is white, but may contain red specks in the 40 mg/12.5 mg and 80 mg/12.5 mg tablets and yellow specks in the 80 mg/25 mg tablets. The telmisartan layer is marked with the Boehringer Ingelheim logo and H4 for the 40 mg/12.5 mg dose strength, H8 for the 80 mg/12.5 mg dose strength and H9 for the 80 mg/25 mg dose strength.
Tablets are provided as follows:
Micardis hct (Telmisartan,hydrochlorothiazide) tablets 40 mg/12.5 mg are individually blister-sealed in cartons of 30 tablets as 3 x 10 cards (NDC 0597-0043-37).
Micardis hct (Telmisartan,hydrochlorothiazide) tablets 80 mg/12.5 mg are individually blister-sealed in cartons of 30 tablets as 3 x 10 cards (NDC 0597-0044-37).
Micardis hct (Telmisartan,hydrochlorothiazide) tablets 80 mg/25 mg are individually blister-sealed in cartons of 30 tablets as 3 x 10 cards (NDC 0597-0042-37).
Micardis hct (Telmisartan,hydrochlorothiazide)
Micardis hct (Telmisartan,hydrochlorothiazide)
Micardis hct (Telmisartan,hydrochlorothiazide)
Micardis hct (Telmisartan,hydrochlorothiazide)
Micardis hct (Telmisartan,hydrochlorothiazide)
Micardis hct (Telmisartan,hydrochlorothiazide)
