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Indications/Uses
Treatment of essential hypertension.
This fixed dose combination is indicated in adult patients whose blood pressure is not adequately controlled on Irbesartan or hydrochlorothiazide alone.
This fixed dose combination is indicated in adult patients whose blood pressure is not adequately controlled on Irbesartan or hydrochlorothiazide alone.
Dosage/Direction for Use
Irbezyd H can be taken once daily, with or without food.
Dose titration with the individual components (i.e. irbesartan and hydrochlorothiazide) may be recommended.
When clinically appropriate direct change from monotherapy to the fixed combinations may be considered: Irbezyd H 150 mg/12.5 mg may be administered in patients whose blood pressure is not adequately controlled with hydrochlorothiazide or irbesartan 150 mg alone; Irbezyd H 300 mg/12.5 mg may be administered in patients insufficiently controlled by irbesartan 300 mg or by Irbezyd H 150 mg/12.5 mg.
When necessary, Irbezyd H may be administered with another antihypertensive medicinal product.
Renal impairment: due to the hydrochlorothiazide component, Irbezyd H is not recommended for patients with severe renal dysfunction (creatinine clearance <30 ml/min). Loop diuretics are preferred than thiazides in this population. No dosage adjustment is necessary in patients with renal impairment whose renal creatinine clearance is >30 ml/min.
Hepatic impairment: Irbezyd H is not indicated in patients with severe hepatic impairment. Thiazides should be used with caution in patients with impaired hepatic function. No dosage adjustment of Irbezyd H is necessary in patients with mild to moderate hepatic impairment.
Elderly patients: no dosage adjustment of Irbezyd H is necessary in elderly patients.
Paediatric patients: Irbezyd H is not recommended for use in children and adolescents due to a lack of data on safety and efficacy.
Dose titration with the individual components (i.e. irbesartan and hydrochlorothiazide) may be recommended.
When clinically appropriate direct change from monotherapy to the fixed combinations may be considered: Irbezyd H 150 mg/12.5 mg may be administered in patients whose blood pressure is not adequately controlled with hydrochlorothiazide or irbesartan 150 mg alone; Irbezyd H 300 mg/12.5 mg may be administered in patients insufficiently controlled by irbesartan 300 mg or by Irbezyd H 150 mg/12.5 mg.
When necessary, Irbezyd H may be administered with another antihypertensive medicinal product.
Renal impairment: due to the hydrochlorothiazide component, Irbezyd H is not recommended for patients with severe renal dysfunction (creatinine clearance <30 ml/min). Loop diuretics are preferred than thiazides in this population. No dosage adjustment is necessary in patients with renal impairment whose renal creatinine clearance is >30 ml/min.
Hepatic impairment: Irbezyd H is not indicated in patients with severe hepatic impairment. Thiazides should be used with caution in patients with impaired hepatic function. No dosage adjustment of Irbezyd H is necessary in patients with mild to moderate hepatic impairment.
Elderly patients: no dosage adjustment of Irbezyd H is necessary in elderly patients.
Paediatric patients: Irbezyd H is not recommended for use in children and adolescents due to a lack of data on safety and efficacy.
Overdosage
Irbesartan: No data are available in regard to overdosage in humans. However, daily doses of 900 mg for 8 weeks were well tolerated. The most likely manifestations of overdosage are expected to be hypotension and tachycardia; bradycardia might also occur from overdose. Irbesartan is not removed by hemodialysis.
In managing overdose, consider the possibilities of multipledrug interactions, drug-drug interactions, and unusual drug kinetics in the patient.
Laboratory determinations of serum levels of irbesartan are not widely available, and such determinations have, in any event, no established role in the management of irbesartan overdose.
Acute oral toxicity studies with irbesartan in mice and rats indicated acute lethal doses were in excess of 2000 mg/kg, about 25- and 50-fold the maximum recommended human dose (300 mg) on a mg/m2 basis, respectively.
Hydrochlorothiazide: The most common signs and symptoms of overdose observed in humans 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.
In managing overdose, consider the possibilities of multipledrug interactions, drug-drug interactions, and unusual drug kinetics in the patient.
Laboratory determinations of serum levels of irbesartan are not widely available, and such determinations have, in any event, no established role in the management of irbesartan overdose.
Acute oral toxicity studies with irbesartan in mice and rats indicated acute lethal doses were in excess of 2000 mg/kg, about 25- and 50-fold the maximum recommended human dose (300 mg) on a mg/m2 basis, respectively.
Hydrochlorothiazide: The most common signs and symptoms of overdose observed in humans 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.
Administration
May be taken with or without food.
Contraindications
Irbezyd H is contraindicated in patients who are hypersensitive to any component of this product. Because of the hydrochlorothiazide component, this product is contraindicated in patients with anuria or hypersensitivity to other sulfonamide-derived drugs.
Special Precautions
General: Irbesartan-Hydrochlorothiazide: In double-blind clinical trials of various doses of irbesartan and hydrochlorothiazide, the incidence of hypertensive patients who developed hypokalemia (serum potassium <3.5 mEq/L) was 7.5% versus 6.0% for placebo; the incidence of hyperkalemia (serum potassium >5.7 mEq/L) was <1.0% versus 1.7% for placebo. No patient discontinued due to increases or decreases in serum potassium. Overall, the combination of irbesartan and hydrochlorothiazide had no effect on serum potassium.
Higher doses of irbesartan ameliorated the hypokalemic response to hydrochlorothiazide.
Hydrochlorothiazide: Periodic determination of serum electrolytes to detect possible electrolyte imbalance should be performed at appropriate intervals. All patients receiving thiazide therapy should be observed for clinical signs of fluid or electrolyte imbalance: hyponatremia, hypochloremic alkalosis, and hypokalemia. Serum and urine electrolyte determinations are particularly important when the patient is vomiting excessively or receiving parenteral fluids. Warning signs or symptoms of fluid and electrolyte imbalance, irrespective of cause, include dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, confusion, seizures, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting.
Hypokalemia may develop, especially with brisk diuresis, when severe cirrhosis is present, or after prolonged therapy. Interference with adequate oral electrolyte intake will also contribute to hypokalemia. Hypokalemia may cause cardiac arrhythmia and may also sensitize or exaggerate the response of the heart to the toxic effects of digitalis (e.g., increased ventricular irritability).
Although any chloride deficit is generally mild and usually does not require specific treatment except under extraordinary circumstances (as in liver disease or renal disease), chloride replacement may be required in the treatment of metabolic alkalosis.
Dilutional hyponatremia may occur in edematous patients in hot weather; appropriate therapy is water restriction, rather than administration of salt except in rare instances when the hyponatremia is life-threatening. In actual salt depletion, appropriate replacement is the therapy of choice. Hyperuricemia may occur or frank gout may be precipitated in certain patients receiving thiazide therapy.
In diabetic patients dosage adjustments of insulin or oral hypoglycemic agents may be required. Hyperglycemia may occur with thiazide diuretics. Thus latent diabetes mellitus may become manifest during thiazide therapy.
The antihypertensive effects of the drug may be enhanced in the post sympathectomy patient. If progressive renal impairment becomes evident consider withholding or discontinuing diuretic therapy.
Thiazides have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia.
Thiazides may decrease urinary calcium excretion.
Thiazides may cause intermittent and slight elevation of serum calcium in the absence of known disorders of calcium metabolism. Marked hypercalcemia may be evidence of hidden hyperparathyroidism. Thiazides should be discontinued before carrying out tests for parathyroid function.
Increases in cholesterol and triglyceride levels may be associated with thiazide diuretic therapy.
Impaired Renal Function: As a consequence of inhibiting the renin-angiotensin aldosterone system, changes in renal function may be anticipated in susceptible individuals. In patients whose renal function may depend on the activity of the renin angiotensin-aldosterone system (e.g., patients with severe congestive heart failure), treatment with angiotensin converting enzyme inhibitors has been associated with oliguria and/or progressive azotemia and (rarely) with acute renal failure and/or death. Irbesartan would be expected to behave similarly. In studies of ACE inhibitors in patients with unilateral or bilateral renal artery stenosis, increases in serum creatinine or BUN have been reported. There has been no known use of irbesartan in patients with unilateral or bilateral renal artery stenosis, but a similar effect should be anticipated.
Thiazides should be used with caution in severe renal disease. In patients with renal disease, thiazides may precipitate azotemia. Cumulative effects of the drug may develop in patients with impaired renal function.
Information for Patients: Symptomatic Hypotension: A patient receiving Irbezyd H (irbesartan-hydrochlorothiazide) Tablets should be cautioned that lightheadedness can occur, especially during the first days of therapy, and that it should be reported to the prescribing physician. The patients should be told that if syncope occurs, Irbezyd H should be discontinued until the physician has been consulted.
All patients should be cautioned 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.
Use in Pregnancy: Female patients of childbearing age should be told about the consequences of second- and third-trimester exposure to drugs that act on the renin-angiotensin system, and they should also be told that these consequences do not appear to have resulted from intrauterine drug exposure that has been limited to the first trimester. These patients should be asked to report pregnancies to their physicians as soon as possible.
Use in Lactation: It is not known whether irbesartan is excreted in human milk, but irbesartan or some metabolite of irbesartan is secreted at low concentration in the milk of lactating rats. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Thiazides appear in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Use in Children: Safety and effectiveness in pediatric patients have not been established.
Use in Elderly: Clinical studies of Irbezyd H did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. 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 deceased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.
Higher doses of irbesartan ameliorated the hypokalemic response to hydrochlorothiazide.
Hydrochlorothiazide: Periodic determination of serum electrolytes to detect possible electrolyte imbalance should be performed at appropriate intervals. All patients receiving thiazide therapy should be observed for clinical signs of fluid or electrolyte imbalance: hyponatremia, hypochloremic alkalosis, and hypokalemia. Serum and urine electrolyte determinations are particularly important when the patient is vomiting excessively or receiving parenteral fluids. Warning signs or symptoms of fluid and electrolyte imbalance, irrespective of cause, include dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, confusion, seizures, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting.
Hypokalemia may develop, especially with brisk diuresis, when severe cirrhosis is present, or after prolonged therapy. Interference with adequate oral electrolyte intake will also contribute to hypokalemia. Hypokalemia may cause cardiac arrhythmia and may also sensitize or exaggerate the response of the heart to the toxic effects of digitalis (e.g., increased ventricular irritability).
Although any chloride deficit is generally mild and usually does not require specific treatment except under extraordinary circumstances (as in liver disease or renal disease), chloride replacement may be required in the treatment of metabolic alkalosis.
Dilutional hyponatremia may occur in edematous patients in hot weather; appropriate therapy is water restriction, rather than administration of salt except in rare instances when the hyponatremia is life-threatening. In actual salt depletion, appropriate replacement is the therapy of choice. Hyperuricemia may occur or frank gout may be precipitated in certain patients receiving thiazide therapy.
In diabetic patients dosage adjustments of insulin or oral hypoglycemic agents may be required. Hyperglycemia may occur with thiazide diuretics. Thus latent diabetes mellitus may become manifest during thiazide therapy.
The antihypertensive effects of the drug may be enhanced in the post sympathectomy patient. If progressive renal impairment becomes evident consider withholding or discontinuing diuretic therapy.
Thiazides have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia.
Thiazides may decrease urinary calcium excretion.
Thiazides may cause intermittent and slight elevation of serum calcium in the absence of known disorders of calcium metabolism. Marked hypercalcemia may be evidence of hidden hyperparathyroidism. Thiazides should be discontinued before carrying out tests for parathyroid function.
Increases in cholesterol and triglyceride levels may be associated with thiazide diuretic therapy.
Impaired Renal Function: As a consequence of inhibiting the renin-angiotensin aldosterone system, changes in renal function may be anticipated in susceptible individuals. In patients whose renal function may depend on the activity of the renin angiotensin-aldosterone system (e.g., patients with severe congestive heart failure), treatment with angiotensin converting enzyme inhibitors has been associated with oliguria and/or progressive azotemia and (rarely) with acute renal failure and/or death. Irbesartan would be expected to behave similarly. In studies of ACE inhibitors in patients with unilateral or bilateral renal artery stenosis, increases in serum creatinine or BUN have been reported. There has been no known use of irbesartan in patients with unilateral or bilateral renal artery stenosis, but a similar effect should be anticipated.
Thiazides should be used with caution in severe renal disease. In patients with renal disease, thiazides may precipitate azotemia. Cumulative effects of the drug may develop in patients with impaired renal function.
Information for Patients: Symptomatic Hypotension: A patient receiving Irbezyd H (irbesartan-hydrochlorothiazide) Tablets should be cautioned that lightheadedness can occur, especially during the first days of therapy, and that it should be reported to the prescribing physician. The patients should be told that if syncope occurs, Irbezyd H should be discontinued until the physician has been consulted.
All patients should be cautioned 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.
Use in Pregnancy: Female patients of childbearing age should be told about the consequences of second- and third-trimester exposure to drugs that act on the renin-angiotensin system, and they should also be told that these consequences do not appear to have resulted from intrauterine drug exposure that has been limited to the first trimester. These patients should be asked to report pregnancies to their physicians as soon as possible.
Use in Lactation: It is not known whether irbesartan is excreted in human milk, but irbesartan or some metabolite of irbesartan is secreted at low concentration in the milk of lactating rats. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Thiazides appear in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Use in Children: Safety and effectiveness in pediatric patients have not been established.
Use in Elderly: Clinical studies of Irbezyd H did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. 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 deceased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.
Use In Pregnancy & Lactation
Use in Pregnancy: Female patients of childbearing age should be told about the consequences of second- and third-trimester exposure to drugs that act on the renin-angiotensin system, and they should also be told that these consequences do not appear to have resulted from intrauterine drug exposure that has been limited to the first trimester. These patients should be asked to report pregnancies to their physicians as soon as possible.
Use in Lactation: It is not known whether irbesartan is excreted in human milk, but irbesartan or some metabolite of irbesartan is secreted at low concentration in the milk of lactating rats. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Thiazides appear in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Use in Lactation: It is not known whether irbesartan is excreted in human milk, but irbesartan or some metabolite of irbesartan is secreted at low concentration in the milk of lactating rats. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Thiazides appear in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Adverse Reactions
Irbesartan-hydrochlorothiazide: Irbezyd H (irbesartan-hydrochlorothiazide) Tablets has been evaluated for safety in 898 patients treated for essential hypertension. In clinical trials with Irbezyd H, no adverse experiences peculiar to this combination drug product have been observed. Adverse experiences have been limited to those that were reported previously with irbesartan and/or hydrochlorothiazide (HCTZ). The overall incidence of adverse experiences reported with the combination was comparable to placebo. In general, treatment with Irbezyd H was well tolerated. For the most part, adverse experiences have been mild and transient in nature and have not required discontinuation of therapy. In controlled clinical trials, discontinuation of Irbezyd H therapy due to clinical adverse experiences was required in only 3.6%. This incidence was significantly less (p=0.023) than the 6.8% of patients treated with placebo who discontinued therapy.
The following adverse events were also reported at a rate of 1% or greater, but were as, or more, common in the placebo group: headache, sinus abnormality, cough, URI, pharyngitis, diarrhea, rhinitis, urinary tract infection, rash, anxiety/nervousness, and muscle cramp.
Adverse events occurred at about the same rates in men and women, older and younger patients, and black and nonblack patients.
Irbesartan: Other adverse experiences that have been reported with irbesartan, without regard to causality are listed as follows: Body as a Whole: fever, chills, orthostatic effects, facial edema, upper extremity edema.
Cardiovascular: flushing, hypertension, cardiac murmur, myocardial infarction, angina pectoris, hypotension, syncope, arrhythmic/conduction disorder, cardiorespiratory arrest, heart failure, hypertensive crisis.
Dermatologic: pruritus, dermatitis, ecchymosis, erythema face, urticaria.
Endocrine/Metabolic/Electrolyte Imbalances: sexual dysfunction, libido change, gout.
Gastrointestinal: diarrhea, constipation, gastroenteritis, flatulence, abdominal distention.
Musculoskeletal/Connective Tissue: musculoskeletal trauma, extremity swelling, muscle cramp, arthritis, muscle ache, musculoskeletal chest pain, joint stiffness, bursitis, muscle weakness.
Nervous System: anxiety/nervousness, sleep disturbance, numbness, somnolence, vertigo, emotional disturbance, depression, paresthesia, tremor, transient ischemic attack, cerebrovascular accident.
Renal/Genitourinary: prostate disorder.
Respiratory: cough, upper respiratory infection, epistaxis, tracheobronchitis, congestion, pulmonary congestion, dyspnea, wheezing.
Special Senses: vision disturbance, hearing abnormality, ear infection, ear pain, conjunctivitis.
Hydrochlorothiazide: Other adverse experiences that have been reported with hydrochlorothiazide, without regard to causality, are listed as follows: 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, hyperuricemia.
Musculoskeletal: muscle spasm.
Nervous System/Psychiatric: restlessness.
Renal: renal failure, renal dysfunction, interstitial nephritis.
Skin: erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis.
Special Senses: transient blurred vision, xanthopsia.
The following adverse events were also reported at a rate of 1% or greater, but were as, or more, common in the placebo group: headache, sinus abnormality, cough, URI, pharyngitis, diarrhea, rhinitis, urinary tract infection, rash, anxiety/nervousness, and muscle cramp.
Adverse events occurred at about the same rates in men and women, older and younger patients, and black and nonblack patients.
Irbesartan: Other adverse experiences that have been reported with irbesartan, without regard to causality are listed as follows: Body as a Whole: fever, chills, orthostatic effects, facial edema, upper extremity edema.
Cardiovascular: flushing, hypertension, cardiac murmur, myocardial infarction, angina pectoris, hypotension, syncope, arrhythmic/conduction disorder, cardiorespiratory arrest, heart failure, hypertensive crisis.
Dermatologic: pruritus, dermatitis, ecchymosis, erythema face, urticaria.
Endocrine/Metabolic/Electrolyte Imbalances: sexual dysfunction, libido change, gout.
Gastrointestinal: diarrhea, constipation, gastroenteritis, flatulence, abdominal distention.
Musculoskeletal/Connective Tissue: musculoskeletal trauma, extremity swelling, muscle cramp, arthritis, muscle ache, musculoskeletal chest pain, joint stiffness, bursitis, muscle weakness.
Nervous System: anxiety/nervousness, sleep disturbance, numbness, somnolence, vertigo, emotional disturbance, depression, paresthesia, tremor, transient ischemic attack, cerebrovascular accident.
Renal/Genitourinary: prostate disorder.
Respiratory: cough, upper respiratory infection, epistaxis, tracheobronchitis, congestion, pulmonary congestion, dyspnea, wheezing.
Special Senses: vision disturbance, hearing abnormality, ear infection, ear pain, conjunctivitis.
Hydrochlorothiazide: Other adverse experiences that have been reported with hydrochlorothiazide, without regard to causality, are listed as follows: 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, hyperuricemia.
Musculoskeletal: muscle spasm.
Nervous System/Psychiatric: restlessness.
Renal: renal failure, renal dysfunction, interstitial nephritis.
Skin: erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis.
Special Senses: transient blurred vision, xanthopsia.
Drug Interactions
Irbesartan: No significant drug-drug pharmacokinetic (or pharmacodynamic) interactions have been found in interaction studies with hydrochlorothiazide, digoxin, warfarin, and nifedipine.
In vitro studies show significant inhibition of the formation of oxidized irbesartan metabolites with the known cytochrome CYP 2C9 substrates/inhibitors sulphenazole, tolbutamide and nifedipine. However, in clinical studies the consequences of concomitant irbesartan on the pharmacodynamics of warfarin were negligible. Concomitant nifedipine or hydrochlorothiazide had no effect on irbesartan pharmacokinetics. Based on in vitro data, no interaction would be expected with drugs whose metabolism is dependent upon cytochrome P450 isozymes 1A1, 1A2, 2A6, 2B6, 2D6, 2E1, or 3A4.
In separate studies of patients receiving maintenance doses of warfarin, hydrochlorothiazide, or digoxin, irbesartan administration for 7 days had no effect on the pharmacodynamics of warfarin (prothrombin time) or the pharmacokinetics of digoxin. The pharmacokinetics of irbesartan were not affected by coadministration of nifedipine or hydrochlorothiazide.
Hydrochlorothiazide: When administered concurrently the following drugs may interact with thiazide diuretics: Alcohol, Barbiturates, Or Narcotics: potentiation of orthostatic hypotension may occur.
Antidiabetic Drugs (oral agents and insulin): dosage adjustment of the antidiabetic drug may be required.
Other Antihypertensive Drugs: additive effect or potentiation.
Cholestyramine And Colestipol Resins: absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively.
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.
Skeletal Muscle Relaxants, Nondepolarizing (e.g., Tubocurarine): possible increased responsiveness to the muscle relaxant.
Lithium: should not generally be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Refer to the package insert for lithium preparations before use of such preparations with Irbezyd H.
Non-steroidal Anti-inflammatory Drugs: in some patients, the administration of a nonsteroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when Irbezyd H (irbesartan hydrochlorothiazide) Tablets and non-steroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.
In vitro studies show significant inhibition of the formation of oxidized irbesartan metabolites with the known cytochrome CYP 2C9 substrates/inhibitors sulphenazole, tolbutamide and nifedipine. However, in clinical studies the consequences of concomitant irbesartan on the pharmacodynamics of warfarin were negligible. Concomitant nifedipine or hydrochlorothiazide had no effect on irbesartan pharmacokinetics. Based on in vitro data, no interaction would be expected with drugs whose metabolism is dependent upon cytochrome P450 isozymes 1A1, 1A2, 2A6, 2B6, 2D6, 2E1, or 3A4.
In separate studies of patients receiving maintenance doses of warfarin, hydrochlorothiazide, or digoxin, irbesartan administration for 7 days had no effect on the pharmacodynamics of warfarin (prothrombin time) or the pharmacokinetics of digoxin. The pharmacokinetics of irbesartan were not affected by coadministration of nifedipine or hydrochlorothiazide.
Hydrochlorothiazide: When administered concurrently the following drugs may interact with thiazide diuretics: Alcohol, Barbiturates, Or Narcotics: potentiation of orthostatic hypotension may occur.
Antidiabetic Drugs (oral agents and insulin): dosage adjustment of the antidiabetic drug may be required.
Other Antihypertensive Drugs: additive effect or potentiation.
Cholestyramine And Colestipol Resins: absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively.
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.
Skeletal Muscle Relaxants, Nondepolarizing (e.g., Tubocurarine): possible increased responsiveness to the muscle relaxant.
Lithium: should not generally be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Refer to the package insert for lithium preparations before use of such preparations with Irbezyd H.
Non-steroidal Anti-inflammatory Drugs: in some patients, the administration of a nonsteroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when Irbezyd H (irbesartan hydrochlorothiazide) Tablets and non-steroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.
Storage
Store at temperatures no exceeding 30°C.
Action
Pharmacology: Pharmacodynamics: Mechanism of Action: Irbesartan: Angiotensin II is a potent vasoconstrictor 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 (RAS) and also stimulates aldosterone synthesis and secretion by adrenal cortex, cardiac contraction, renal resorption of sodium, activity of the sympathetic nervous system, and smooth muscle cell growth. Irbesartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively binding to the AT1 angiotensin II receptor. There is also an AT2 receptor in many tissues, but it is not involved in cardiovascular homeostasis.
Irbesartan is a specific competitive antagonist of AT1 receptors with a much greater affinity (more than 8500-fold) for the AT1 receptor than for the AT2 receptor, and no agonist activity.
Blockade of the AT1 receptor removes the negative feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and circulating angiotensin II do not overcome the effects of irbesartan on blood pressure.
Irbesartan does not inhibit ACE or renin or affect other hormone receptors or ion channels known to be involved in the cardiovascular regulation of blood pressure and sodium homeostasis. Because irbesartan does not inhibit ACE, it does not affect the response to bradykinin; whether this has clinical relevance is not known.
Hydrochlorothiazide: Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly increasing excretion of sodium 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.
Pharmacokinetics: Irbesartan: Irbesartan is an orally active agent that does not require biotransformation into an active form. The oral absorption of irbesartan is rapid and complete with an average absolute bioavailability of 60–80%. Following oral administration of irbesartan, peak plasma concentrations of irbesartan are attained at 1.5-2 hours after dosing. Food does not affect the bioavailability of irbesartan.
Irbesartan exhibits linear pharmacokinetics over the therapeutic dose range.
The terminal elimination half-life of irbesartan averaged 11-15 hours. Steady-state concentrations are achieved within 3 days. Limited accumulation of irbesartan (<20%) is observed in plasma upon repeated once-daily dosing.
Hydrochlorothiazide: 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.
Metabolism and Elimination: Irbesartan: Irbesartan is metabolized via glucuronide conjugation and oxidation. Following oral or intravenous administration of 14C-labeled irbesartan, more than 80% of the circulating plasma radioactivity is attributable to unchanged irbesartan. The primary circulating metabolite is the inactive irbesartan glucuronide conjugate (approximately 6%). The remaining oxidative metabolites do not add appreciably to irbesartan's pharmacologic activity.
Irbesartan and its metabolites are excreted by both biliary and renal routes. Following either oral or intravenous administration of 14C-labeled irbesartan, about 20% of radioactivity is recovered in the urine and the remainder in the feces, as irbesartan or irbesartan glucuronide.
In vitro studies of irbesartan oxidation by cytochrome P450 isoenzymes indicated irbesartan was oxidized primarily by 2C9; metabolism by 3A4 was negligible. Irbesartan was neither metabolized by, nor did it substantially induce or inhibit, isoenzymes commonly associated with drug metabolism (1A1, 1A2, 2A6, 2B6, 2D6, 2E1). There was no induction or inhibition of 3A4.
Hydrochlorothiazide: Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. At least 61% of the oral dose is eliminated unchanged within 24 hours.
Distribution: Irbesartan: Irbesartan is 90% bound to serum proteins (primarily albumin and α1-acid glycoprotein) with negligible binding to cellular components of blood. The average volume of distribution is 53-93 liters. Total plasma and renal clearances are in the range of 157-176 and 3.0-3.5 mL/min, respectively. With repetitive dosing, irbesartan accumulates to no clinically relevant extent.
Studies in animals indicate that radiolabeled irbesartan weakly crosses the blood-brain barrier and placenta.
Irbesartan is excreted in the milk of lactating rats.
Hydrochlorothiazide: Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.
Special Populations: Pediatric: Irbesartan-hydrochlorothiazide pharmacokinetics have not been investigated in patients <18 years of age.
Gender: No gender related differences in pharmacokinetics were observed in healthy elderly (age 65-80 years) or in healthy young (age 18-40 years) subjects. In studies of hypertensive patients, there was no gender difference in half-life or accumulation, but somewhat higher plasma concentrations of irbesartan were observed in females (11-44%). No gender-related dosage adjustment is necessary.
Geriatric: In elderly subjects (age 65-80 years), irbesartan elimination half-life was not significantly altered, but AUC and Cmax values were about 20-50% greater than those of young subjects (age 18-40 years). No dosage adjustment is necessary in the elderly.
Race: In healthy black subjects, Irbesartan AUC values were approximately 25% greater than whites; there were no differences in Cmax values.
Renal Insufficiency: The pharmacokinetics of irbesartan were not altered in patients with renal impairment or in patients on hemodialysis. Irbesartan is not removed by hemodialysis. No dosage adjustment is necessary in patients with mild to severe renal impairment unless a patient with renal impairment is also volume depleted.
Hepatic Insufficiency: The pharmacokinetics of irbesartan following repeated oral administration were not significantly affected in patients with mild to moderate cirrhosis of the liver. No dosage adjustment is necessary in patients with hepatic insufficiency.
Irbesartan is a specific competitive antagonist of AT1 receptors with a much greater affinity (more than 8500-fold) for the AT1 receptor than for the AT2 receptor, and no agonist activity.
Blockade of the AT1 receptor removes the negative feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and circulating angiotensin II do not overcome the effects of irbesartan on blood pressure.
Irbesartan does not inhibit ACE or renin or affect other hormone receptors or ion channels known to be involved in the cardiovascular regulation of blood pressure and sodium homeostasis. Because irbesartan does not inhibit ACE, it does not affect the response to bradykinin; whether this has clinical relevance is not known.
Hydrochlorothiazide: Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly increasing excretion of sodium 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.
Pharmacokinetics: Irbesartan: Irbesartan is an orally active agent that does not require biotransformation into an active form. The oral absorption of irbesartan is rapid and complete with an average absolute bioavailability of 60–80%. Following oral administration of irbesartan, peak plasma concentrations of irbesartan are attained at 1.5-2 hours after dosing. Food does not affect the bioavailability of irbesartan.
Irbesartan exhibits linear pharmacokinetics over the therapeutic dose range.
The terminal elimination half-life of irbesartan averaged 11-15 hours. Steady-state concentrations are achieved within 3 days. Limited accumulation of irbesartan (<20%) is observed in plasma upon repeated once-daily dosing.
Hydrochlorothiazide: 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.
Metabolism and Elimination: Irbesartan: Irbesartan is metabolized via glucuronide conjugation and oxidation. Following oral or intravenous administration of 14C-labeled irbesartan, more than 80% of the circulating plasma radioactivity is attributable to unchanged irbesartan. The primary circulating metabolite is the inactive irbesartan glucuronide conjugate (approximately 6%). The remaining oxidative metabolites do not add appreciably to irbesartan's pharmacologic activity.
Irbesartan and its metabolites are excreted by both biliary and renal routes. Following either oral or intravenous administration of 14C-labeled irbesartan, about 20% of radioactivity is recovered in the urine and the remainder in the feces, as irbesartan or irbesartan glucuronide.
In vitro studies of irbesartan oxidation by cytochrome P450 isoenzymes indicated irbesartan was oxidized primarily by 2C9; metabolism by 3A4 was negligible. Irbesartan was neither metabolized by, nor did it substantially induce or inhibit, isoenzymes commonly associated with drug metabolism (1A1, 1A2, 2A6, 2B6, 2D6, 2E1). There was no induction or inhibition of 3A4.
Hydrochlorothiazide: Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. At least 61% of the oral dose is eliminated unchanged within 24 hours.
Distribution: Irbesartan: Irbesartan is 90% bound to serum proteins (primarily albumin and α1-acid glycoprotein) with negligible binding to cellular components of blood. The average volume of distribution is 53-93 liters. Total plasma and renal clearances are in the range of 157-176 and 3.0-3.5 mL/min, respectively. With repetitive dosing, irbesartan accumulates to no clinically relevant extent.
Studies in animals indicate that radiolabeled irbesartan weakly crosses the blood-brain barrier and placenta.
Irbesartan is excreted in the milk of lactating rats.
Hydrochlorothiazide: Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.
Special Populations: Pediatric: Irbesartan-hydrochlorothiazide pharmacokinetics have not been investigated in patients <18 years of age.
Gender: No gender related differences in pharmacokinetics were observed in healthy elderly (age 65-80 years) or in healthy young (age 18-40 years) subjects. In studies of hypertensive patients, there was no gender difference in half-life or accumulation, but somewhat higher plasma concentrations of irbesartan were observed in females (11-44%). No gender-related dosage adjustment is necessary.
Geriatric: In elderly subjects (age 65-80 years), irbesartan elimination half-life was not significantly altered, but AUC and Cmax values were about 20-50% greater than those of young subjects (age 18-40 years). No dosage adjustment is necessary in the elderly.
Race: In healthy black subjects, Irbesartan AUC values were approximately 25% greater than whites; there were no differences in Cmax values.
Renal Insufficiency: The pharmacokinetics of irbesartan were not altered in patients with renal impairment or in patients on hemodialysis. Irbesartan is not removed by hemodialysis. No dosage adjustment is necessary in patients with mild to severe renal impairment unless a patient with renal impairment is also volume depleted.
Hepatic Insufficiency: The pharmacokinetics of irbesartan following repeated oral administration were not significantly affected in patients with mild to moderate cirrhosis of the liver. No dosage adjustment is necessary in patients with hepatic insufficiency.
MedsGo Class
Angiotensin II Antagonists / Diuretics
Features
Brand
Irbezyd- H 150/12.5
Full Details
Dosage Strength
150mg / 12.5mg
Drug Ingredients
- Hydrochlorothiazide
- Irbesartan
Drug Packaging
Tablet 1's
Generic Name
Hydrochlorothiazide / Irbesartan
Dosage Form
Tablet
Registration Number
DRP-7331
Drug Classification
Prescription Drug (RX)