Micardis HCT

Dosage Forms And Strengths

• 40 mg/12.5 mg, red and white tablets marked with the Boehringer Ingelheim logo and H4
• 80 mg/12.5 mg, red and white tablets marked with the Boehringer Ingelheim logo and H8
• 80 mg/25 mg, yellow and white tablets marked with the Boehringer Ingelheim logo and H9

Storage And Handling

MICARDIS HCT is available in three strengths as biconvex two-layered, oblong-shaped, uncoated tablets containing telmisartan and hydrochlorothiazide:

40 mg/12.5 mg tablet: red and white (may contain red specks) marked with the BOEHRINGER INGELHEIM logo and H4; individually blister-sealed in cartons of 30 tablets as 3 x 10 cards (NDC 0597-0043-37)

80 mg/12.5 mg tablet: red and white (may contain red specks) marked with the BOEHRINGER INGELHEIM logo and H8; individually blister-sealed in cartons of 30 tablets as 3 x 10 cards (NDC 0597-0044-37)

80 mg/25 mg tablet: yellow and white (may contain yellow specks) marked with the BOEHRINGER INGELHEIM logo and H9; individually blister-sealed in cartons of 30 tablets as 3 x 10 cards (NDC 0597-0042-37)

Storage

Store at 25°C (77°F); excurs ions permitted to 15°C-30°C (59°F-86°F). Tablets should not be removed from blisters until immediately before administration.

Distributed by: Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877 USA. Revised: Jan 2016

MICARDIS HCT (telmisartan and hydrochlorothiazide) is indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including the classes to which this drug principally belongs. There are no controlled trials demonstrating risk reduction with MICARDIS HCT.

Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than one drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program's Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC).

Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly.

Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal.

Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of therapy.

MICARDIS HCT is not indicated for initial therapy for the treatment of hypertension.

MICARDIS HCT may be used alone or in combination with other antihypertensive agents.

Dosing Information

Initiate a patient whose blood pressure is not adequately controlled with telmisartan monotherapy 80 mg on MICARDIS HCT, 80 mg/12.5 mg once daily. Dose can be titrated up to 160 mg/25 mg after 2 to 4 weeks, if necessary.

Initiate a patient whose blood pressure is not adequately controlled by 25 mg once daily of hydrochlorothiazide, or is controlled but who experiences hypokalemia with this regimen on MICARDIS HCT 80 mg / 12.5 mg once daily. Dose can be titrated up to 160 mg/25 mg after 2 to 4 weeks, if necessary.

Patients titrated to the individual components (telmisartan and hydrochlorothiazide) may instead receive the corresponding dose of MICARDIS HCT.

MICARDIS HCT may be administered with other antihypertensive drugs.

Dose Adjustment For Hepatic Impairment

Initiate patients with biliary obstructive disorders or hepatic insufficiency under close medical supervision using the 40 mg/12.5 mg combination. MICARDIS HCT tablets are not recommended for patients with severe hepatic impairment.

Important Administration Instructions

MICARDIS HCT tablets should not be removed from blisters until immediately before administration.

MICARDIS HCT is contraindicated:

• In patients who are hypersensitive to any component of this product.
• In patients with anuria.
• For co-administration with aliskiren in patients with diabetes.

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Fetal Toxicity

Pregnancy Category D

Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue MICARDIS HCT as soon as possible.

Thiazides cross the placental barrier and appear in cord blood. Adverse reactions include fetal or neonatal jaundice and thrombocytopenia.

Hypotension In Volume- Or Salt-Depleted Patients

In patients with an activated renin-angiotensin system, such as volume- or salt-depleted patients (e.g., those being treated with high doses of diuretics), symptomatic hypotension may occur after initialization of treatment with MICARDIS HCT. Correct volume or salt depletion prior to administration of MICARDIS HCT.

Impaired Renal Function

Changes in renal function including acute renal failure can be caused by drugs that inhibit the reninangiotensin system and by diuretics. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe congestive heart failure, or volume depletion) may be at particular risk of developing oliguria, progressive azotemia, or acute renal failure on MICARDIS HCT. Monitor renal function periodically in these patients. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on MICARDIS HCT.

Electrolytes And Metabolic Disorders

Drugs, including telmisartan, that inhibit the renin-angiotensin system can cause hyperkalemia, particularly in patients with renal insufficiency, diabetes, or combination use with other angiotensin receptor blockers or ACE inhibitors and the concomitant use of other drugs that raise serum potassium levels.

Hydrochlorothiazide can cause hypokalemia and hyponatremia. Thiazides have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia. Hypomagnesemia can result in hypokalemia which may be difficult to treat despite potassium repletion. Monitor serum electrolytes periodically.

In controlled trials using the telmisartan/hydrochlorothiazide combination treatment, no patient administered 40 mg/12.5 mg, 80 mg/12.5 mg, or 80 mg/25 mg experienced a decrease in potassium ≥ 1.4 mEq/L, and no patient experienced hyperkalemia.

Hydrochlorothiazide decreases urinary calcium excretion and may cause elevations of serum calcium.

Hydrochlorothiazide may alter glucose tolerance and raise serum levels of cholesterol and triglycerides.

Hyperuricemia may occur or frank gout may be precipitated in certain patients receiving thiazide therapy. Because telmisartan decreases uric acid, telmisartan in combination with hydrochlorothiazide attenuates the diuretic-induced hyperuricemia.

Hypersensitivity Reaction

Hydrochlorothiazide

Hypersensitivity reactions to hydrochlorothiazide may occur in patients with or without a history of allergy or bronchial asthma, but are more likely in patients with such a history.

Acute Myopia And Secondary Angle-Closure Glaucoma

Hydrochlorothiazide, a sulfonamide, can cause an idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma. Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue hydrochlorothiazide as rapidly as possible. Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled. Risk factors for developing acute angleclosure glaucoma may include a history of sulfonamide or penicillin allergy.

Systemic Lupus Erythematosus

Thiazide diuretics have been reported to cause exacerbation or activation of systemic lupus erythematosus.

Postsympathectomy Patients

The antihypertensive effects of hydrochlorothiazide may be enhanced in the postsympathectomy patient.

Patient Counseling Information

Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION).

Pregnancy

Advise female patients of childbearing age about the consequences of exposure to MICARDIS HCT during pregnancy. Discuss treatment options with women planning to become pregnant. Tell patients to report pregnancies to their physicians as soon as possible.

Symptomatic Hypotension And Syncope

Advise patients that lightheadedness can occur, especially during the first days of therapy, and to report it to their healthcare provider. Inform patients that inadequate fluid intake, excessive perspiration, diarrhea, or vomiting can lead to an excessive fall in blood pressure, with the same consequences of lightheadedness and possible syncope. Advise patients to contact their healthcare provider if syncope occurs.

Potassium Supplements

Advise patients not to use potassium supplements or salt substitutes that contain potassium without consulting the prescribing healthcare provider.

Acute Myopia And Secondary Angle-Closure Glaucoma

Advise patients to discontinue MICARDIS HCT and seek immediate medical attention if they experience symptoms of Acute Myopia or Secondary Angle-Closure Glaucoma.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Telmisartan and Hydrochlorothiazide

No carcinogenicity, mutagenicity, or fertility studies have been conducted with the combination of telmisartan and hydrochlorothiazide.

Telmisartan

There was no evidence of carcinogenicity when telmisartan was administered in the diet to mice and rats for up to 2 years. The highest doses administered to mice (1000 mg/kg/day) and rats (100 mg/kg/day) are, on a mg/m² basis, about 59 and 13 times, respectively, the maximum recommended human dose (MRHD) of telmisartan. These same doses have been shown to provide average systemic exposures to telmisartan > 100 times and > 25 times, respectively, the systemic exposure in humans receiving the MRHD of telmisartan (80 mg/day).

Genotoxicity assays did not reveal any telmisartan-related effects at either the gene or chromosome level. These assays included bacterial mutagenicity tests with Salmonella and E. coli (Ames), a gene mutation test with Chinese hamster V79 cells, a cytogenetic test with human lymphocytes, and a mouse micronucleus test.

No drug-related effects on the reproductive performance of male and female rats were noted at 100 mg/kg/day (the highest dose administered), about 13 times, on a mg/m basis, the MRHD of telmisartan. This dose in the rat resulted in an average systemic exposure (telmisartan AUC as determined on day 6 of pregnancy) at least 50 times the average systemic exposure in humans at the MRHD (80 mg/day).

Hydrochlorothiazide

Two-year feeding studies in mice and rats conducted under the auspices of the National Toxicology Program (NTP) uncovered no evidence of a carcinogenic potential of hydrochlorothiazide in female mice (at doses of up to approximately 600 mg/kg/day) or in male and female rats (at doses of up to approximately 100 mg/kg/day). The NTP, however, found equivocal evidence for hepatocarcinogenicity in male mice.

Hydrochlorothiazide was not genotoxic in vitro in the Ames mutagenicity assay of Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537, and TA 1538 and in the Chinese Hamster Ovary (CHO) test for chromosomal aberrations, or in vivo in assays using mouse germinal cell chromosomes, Chinese hamster bone marrow chromosomes, and the Drosophila sex-linked recessive lethal trait gene. Positive test results were obtained in the in vitro CHO Sister Chromatid Exchange (clastogenicity) assay, in the Mouse Lymphoma Cell (mutagenicity) assay, and in the Aspergillus nidulans non-disjunction assay.

Hydrochlorothiazide had no adverse effects on the fertility of mice and rats of either sex in studies wherein these species were exposed, via their diet, to doses of up to 100 and 4 mg/kg, respectively, prior to mating and throughout gestation.

Developmental Toxicity

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.

There is no clinical experience with the use of telmisartan in pregnant women. 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 of up to 45 mg/kg/day. In rabbits, embryo lethality associated with maternal toxicity (reduced body weight gain and food consumption) was observed at 45 mg/kg/day (approximately 12 times the maximum recommended human dose [MRHD] of 80 mg on a mg/m² basis). In rats, maternally toxic (reduced body weight gain and food consumption) telmisartan doses of 15 mg/kg/day (approximately 1.9 times the MRHD on a mg/m² 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 approximately 0.64 and 3.7 times, respectively, on a mg/m basis, the MRHD 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.

Use In Specific Populations

Pregnancy

Pregnancy Category D

Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue MICARDIS HCT as soon as possible. These adverse outcomes are usually associated with use of these drugs in the second and third trimester of pregnancy. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents. Appropriate management of maternal hypertension during pregnancy is important to optimize outcomes for both mother and fetus.

In the unusual case that there is no appropriate alternative to therapy with drugs affecting the reninangiotensin system for a particular patient, apprise the mother of the potential risk to the fetus. Perform serial ultrasound examinations to assess the intra-amniotic environment. If oligohydramnios is observed, discontinue MICARDIS HCT, unless it is considered lifesaving for the mother. Fetal testing may be appropriate, based on the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe infants with histories of in utero exposure to MICARDIS HCT for hypotension, oliguria, and hyperkalemia.

Nursing Mothers

It is not known whether telmisartan is excreted in human milk, but telmisartan was shown to be present in the milk of lactating rats. Thiazides appear in human milk. Because of the potential for adverse effects on the nursing infant, decide whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness of MICARDIS HCT in pediatric patients have not been established.

Infants with histories of in utero exposure to an angiotensin II receptor antagonist should be closely observed for hypotension, oliguria, and hyperkalemia. If oliguria occurs, support blood pressure and renal perfusion. Exchange transfusion or dialysis may be required as means of reversing hypotension and/or substituting for disordered renal function.

Geriatric Use

In the controlled clinical trials (n=1017), approximately 20% of patients treated with telmisartan/hydrochlorothiazide were 65 years of age or older, and 5% were 75 years of age or older. No overall differences in effectiveness and safety of telmisartan/hydrochlorothiazide were observed in these patients compared to younger patients. Other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function and of concomitant diseases or other drug therapy.

Use In Patients With Hepatic Impairment

Patients with biliary obstructive disorders or hepatic insufficiency should initiate treatment under close medical supervision using the 40 mg/12.5 mg combination.

Telmisartan

As the majority of telmisartan is eliminated by biliary excretion, patients with biliary obstructive disorders or hepatic insufficiency can be expected to have reduced clearance and higher blood levels.

Hydrochlorothiazide

Minor alterations of fluid and electrolyte balance may precipitate hepatic coma in patients with impaired hepatic function or progressive liver disease.

Use In Patients With Renal Impairment

Safety and effectiveness of MICARDIS HCT in patients with severe renal impairment (CrCl ≤ 30 mL/min) have not been established. In patients with severe renal impairment, MICARDIS HCT tablets are not recommended. No dose adjustment is required in patients with mild (CrCl 60 to 90 mL/min) or moderate (CrCl 30 to 60 mL/min) renal impairment.

Hydrochlorothiazide

Alcohol, barbiturates, or narcotics: Potentiation of orthostatic hypotension may occur.

Skeletal muscle relaxants: Possible increased responsiveness to muscle relaxants such as curare derivatives.

Corticosteroids, ACTH: Intensified electrolyte depletion, particularly hypokalemia.

Pressor amines (e.g., norepinephrine): Possible decreased response to pressor amines but not sufficient to preclude their use.

Pregnancy Category D

Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue MICARDIS HCT as soon as possible. These adverse outcomes are usually associated with use of these drugs in the second and third trimester of pregnancy. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents. Appropriate management of maternal hypertension during pregnancy is important to optimize outcomes for both mother and fetus.

In the unusual case that there is no appropriate alternative to therapy with drugs affecting the reninangiotensin system for a particular patient, apprise the mother of the potential risk to the fetus. Perform serial ultrasound examinations to assess the intra-amniotic environment. If oligohydramnios is observed, discontinue MICARDIS HCT, unless it is considered lifesaving for the mother. Fetal testing may be appropriate, based on the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe infants with histories of in utero exposure to MICARDIS HCT for hypotension, oliguria, and hyperkalemia.

The following adverse reactions are discussed elsewhere in labeling:

• Hypotension
• Renal Impairment
• Electrolytes and Metabolic Disorders

Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

MICARDIS HCT has been evaluated for safety in more than 1700 patients, including 716 treated for hypertension for longer than 6 months and 420 for more than 1 year. Adverse reactions have been limited to those that have been previously reported with telmisartan and/or hydrochlorothiazide.

Adverse reactions occurring at an incidence of ≥ 2% in patients treated with telmisartan/hydrochlorothiazide and at a greater rate than in patients treated with placebo, are presented in Table 1.

Table 1 : Adverse Reactions Occurring at an Incidence of ≥ 2% in Patients Treated with Telmisartan/Hydrochlorothiazide and at a Greater Rate Than in Patients Treated with Placebo*

Other adverse reactions observed for telmisartan/hydrochlorothiazide were: pain (including back and abdominal), dyspepsia, erythema, vomiting, bronchitis, and pharyngitis.

Adverse reactions occurred at approximately the same rates in men and women, older and younger patients, and black and non-black patients.

Telmisartan

Other adverse events that have been reported with telmisartan are listed below:

Autonomic Nervous System: impotence, increased sweating, flushing

Body as a Whole: allergy, fever, leg pain, chest pain

Cardiovascular: palpitation, angina pectoris, abnormal ECG, hypertension, peripheral edema

Central Nervous System: insomnia, somnolence, migraine, paresthesia, involuntary muscle contractions, hypoesthesia

Gastrointestinal: flatulence, constipation, gastritis, dry mouth, hemorrhoids, gastroesophageal reflux, toothache

Hepato-biliary: elevations of liver enzymes or serum bilirubin

Metabolic: gout, hypercholesterolemia, diabetes mellitus

Musculoskeletal: arthritis, arthralgia, leg cramps, myalgia

Psychiatric: anxiety, depression, nervousness

Resistance Mechanism: infection, abscess, otitis media

Respiratory: asthma, rhinitis, dyspnea, epistaxis

Skin: dermatitis, eczema, pruritus

Urinary: micturition frequency, cystitis

Vascular: cerebrovascular disorder

Special Senses: abnormal vision, conjunctivitis, tinnitus, earache

Hydrochlorothiazide

Other adverse events that have been reported with hydrochlorothiazide are listed below:

Body as a Whole: weakness

Digestive: pancreatitis, jaundice (intrahepatic cholestatic jaundice), sialadenitis, cramping, gastric irritation

Hematologic: aplastic anemia, agranulocytosis, leukopenia, hemolytic anemia, thrombocytopenia

Hypersensitivity: purpura, photosensitivity, urticaria, necrotizing angiitis (vasculitis and cutaneous vasculitis), fever, respiratory distress including pneumonitis and pulmonary edema, anaphylactic reactions

Metabolic: hyperglycemia, glycosuria

Musculoskeletal: muscle spasm

Nervous System/Psychiatric: restlessness

Renal: interstitial nephritis

Skin: erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis

Special Senses: transient blurred vision, xanthopsia

Clinical Laboratory Findings

Creatinine, Blood Urea Nitrogen (BUN): Increases in BUN ( ≥ 11.2 mg/dL) and serum creatinine ( ≥ 0.5 mg/dL) were observed in 2.8% and 1.4%, respectively, of patients with essential hypertension treated with MICARDIS HCT tablets in controlled trials. No patient discontinued treatment with MICARDIS HCT tablets because of an increase in BUN or creatinine.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of MICARDIS HCT. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate reliably their frequency or establish a causal relationship to drug exposure.

Blood and Lymphatic System Disorders: eosinophilia

Cardiac Disorders: atrial fibrillation, congestive heart failure, myocardial infarction, tachycardia, bradycardia

Ear and Labyrinth Disorders: vertigo

General Disorders and Administration Site Conditions: asthenia, edema

Hepato-biliary: Abnormal hepatic function / liver disorder

Immune System Disorders: anaphylactic reaction

Infections and Infestations: urinary tract infection

Investigations: increased CPK

Metabolism and Nutrition Disorders: hypoglycemia (in diabetic patients)

Musculoskeletal and Connective Tissue Disorders: tendon pain (including tendonitis, tenosynovitis), rhabdomyolysis

Nervous System Disorders: syncope

Renal and Urinary Disorders: renal failure, renal impairment including acute renal failure

Reproductive System and Breast Disorders: erectile dysfunction

Respiratory, Thoracic and Mediastinal Disorders: coughing

Skin and Subcutaneous Tissue Disorders: drug eruption (toxic skin eruption mostly reported as toxicoderma, rash, and urticaria), angioedema (with fatal outcome)

Vascular Disorder: orthostatic hypotension

Telmisartan

Limited data are available with regard to overdosage of telmisartan in humans. The most likely manifestations of overdosage with telmisartan are hypotension, dizziness, and tachycardia; bradycardia could occur from parasympathetic (vagal) stimulation. If symptomatic hypotension should occur, supportive treatment should be instituted. Telmisartan is not removed by hemodialysis.

Hydrochlorothiazide

The most common signs and symptoms observed in patients with a hydrochlorothiazide overdose are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. If digitalis has also been administered, hypokalemia may accentuate cardiac arrhythmias. The degree to which hydrochlorothiazide is removed by hemodialysis has not been established. The oral LD50 of hydrochlorothiazide is greater than 10 g/kg in both mice and rats.

Telmisartan

In normal volunteers, a dose of telmisartan 80 mg inhibited the pressor response to an intravenous infusion of angiotensin II by approximately 90% at peak plasma concentrations with approximately 40% inhibition persisting for 24 hours.

Plasma concentration of angiotensin II and plasma renin activity increased in a dose-dependent manner after single administration of telmisartan to healthy subjects and repeated administration to hypertensive patients. The once-daily administration of up to 80 mg telmisartan to healthy subjects did not influence plasma aldosterone concentrations. In multiple dose studies with hypertensive patients, there were no clinically significant changes in electrolytes (serum potassium or sodium) or in metabolic function (including serum levels of cholesterol, triglycerides, HDL, LDL, glucose, or uric acid).

The antihypertensive effects of telmisartan have been studied in six placebo-controlled clinical trials including a total of 1773 patients with mild to moderate hypertension (diastolic blood pressure of 95 to 114 mmHg), 1031 of whom were treated with telmisartan. Following once-daily administration of telmisartan, the magnitude of blood pressure reduction from baseline after placebo subtraction was approximately (SBP/DBP) 6-8/6 mmHg for 20 mg, 9-13/6-8 mmHg for 40 mg, and 12-13/7-8 mmHg for 80 mg. Larger doses (up to 160 mg) did not appear to cause a further decrease in blood pressure.

The onset of antihypertensive activity occurs within 3 hours, with a maximal reduction by approximately 4 weeks. At doses of 20, 40, and 80 mg, the antihypertensive effect of once-daily administration of telmisartan was maintained for the full 24-hour dose interval.

In 30 hypertensive patients with normal renal function treated for 8 weeks with telmisartan 80 mg or telmisartan 80 mg in combination with hydrochlorothiazide 12.5 mg, there were no clinically significant changes from baseline in renal blood flow, glomerular filtration rate, filtration fraction, renovascular resistance, or creatinine clearance.

Hydrochlorothiazide

After oral administration of hydrochlorothiazide, diuresis begins within 2 hours, peaks in about 4 hours, and lasts approximately 6 to 12 hours.

Drug Interactions

Hydrochlorothiazide

Alcohol, barbiturates, or narcotics: Potentiation of orthostatic hypotension may occur.

Skeletal muscle relaxants: Possible increased responsiveness to muscle relaxants such as curare derivatives.

Corticosteroids, ACTH: Intensified electrolyte depletion, particularly hypokalemia.

Pressor amines (e.g., norepinephrine): Possible decreased response to pressor amines but not sufficient to preclude their use.

Telmisartan

Absorption

Following oral administration, peak concentrations (Cmax) of telmisartan are reached in 0.5 to 1 hour after dosing. Food slightly reduces the bioavailability of telmisartan, with a reduction in the area under the plasma concentration-time curve (AUC) of approximately 6% with 40 mg and approximately 20% after a 160 mg dose MICARDIS HCT can be administered with or without food. The absolute bioavailability of telmisartan is dose dependent. At 40 and 160 mg the bioavailability was 42% and 58%, respectively. The pharmacokinetics of telmisartan with orally administered MICARDIS are nonlinear over the dose range 20 to 160 mg, with greater than proportional increases of plasma concentrations (Cmax and AUC) with increasing doses. Telmisartan shows bi-exponential decay kinetics with a terminal elimination half-life of approximately 24 hours. Trough plasma concentrations of telmisartan with once-daily dosing are approximately 10% to 25% of peak plasma concentrations. Telmisartan has an accumulation index in plasma of 1.5 to 2.0 upon repeated once-daily dosing.

Distribution

Telmisartan is highly bound to plasma proteins ( > 99.5%), mainly albumin and α1 -acid glycoprotein. Plasma protein binding is constant over the concentration range achieved with recommended doses. The volume of distribution for telmisartan is approximately 500 liters, indicating additional tissue binding.

Metabolism

Telmisartan is metabolized by conjugation to form a pharmacologically inactive acyl glucuronide; the glucuronide of the parent compound is the only metabolite that has been identified in human plasma and urine. After a single dose, the glucuronide represents approximately 11% of the measured radioactivity in plasma. The cytochrome P450 isoenzymes are not involved in the metabolism of telmisartan.

Elimination

Following either intravenous or oral administration of ¹⁴C-labeled telmisartan, most of the administered dose ( > 97%) was eliminated unchanged in feces via biliary excretion; only minute amounts were found in the urine (0.91% and 0.49% of total radioactivity, respectively).

Total plasma clearance of telmisartan is > 800 mL/min. Terminal half-life and total clearance appear to be independent of dose.

Hydrochlorothiazide

Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. When plasma levels have been followed for at least 24 hours, the plasma half-life has been observed to vary between 5.6 and 14.8 hours. At least 61% of the oral dose is eliminated unchanged within 24 hours. Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.