LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE - losartan potassium and hydrochlorothiazide tablet, film coated
Qualitest Pharmaceuticals
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General
Losartan Potassium
Losartan is an orally active agent that undergoes substantial first-pass metabolism by cytochrome P450 enzymes. It is converted, in part, to an active carboxylic acid metabolite that is responsible for most of the angiotensin II receptor antagonism that follows losartan treatment. The terminal half-life of losartan is about 2 hours and of the metabolite is about 6-9 hours. The pharmacokinetics of losartan and its active metabolite are linear with oral losartan doses up to 200 mg and do not change over time. Neither losartan nor its metabolite accumulate in plasma upon repeated once-daily dosing.
Following oral administration, losartan is well absorbed (based on absorption of radio-labeled losartan) and undergoes substantial first-pass metabolism; the systemic bioavailability of losartan is approximately 33%. About 14% of an orally-administered dose of losartan is converted to the active metabolite. Mean peak concentrations of losartan and its active metabolite are reached in 1 hour and in 3-4 hours, respectively. While maximum plasma concentrations of losartan and its active metabolite are approximately equal, the AUC of the metabolite is about 4 times as great as that of losartan. A meal slows absorption of losartan and decreases its Cmax but has only minor effects on losartan AUC or on the AUC of the metabolite (about 10% decreased).
Both losartan and its active metabolite are highly bound to plasma proteins, primarily albumin, with plasma free fractions of 1.3% and 0.2%, respectively. Plasma protein binding is constant over the concentration range achieved with recommended doses. Studies in rats indicate that losartan crosses the blood-brain barrier poorly, if at all.
Losartan metabolites have been identified in human plasma and urine. In addition to the active carboxylic acid metabolite, several inactive metabolites are formed. Following oral and intravenous administration of 14C-labeled losartan potassium, circulating plasma radioactivity is primarily attributed to losartan and its active metabolite. In vitro studies indicate that cytochrome P450 2C9 and 3A4 are involved in the biotransformation of losartan to its metabolites. Minimal conversion of losartan to the active metabolite (less than 1% of the dose compared to 14% of the dose in normal subjects) was seen in about one percent of individuals studied.
Special Populations
Pediatric: Losartan pharmacokinetics have been investigated in patients 6 to 16 years (see PRECAUTIONS, Pediatric Use).
Geriatric and Gender: Losartan pharmacokinetics have been investigated in the elderly (65-75 years) and in both genders. Plasma concentrations of losartan and its active metabolite are similar in elderly and young hypertensives. Plasma concentrations of losartan were about twice as high in female hypertensives as male hypertensives, but concentrations of the active metabolite were similar in males and females.
Race: Pharmacokinetic differences due to race have not been studied (see also PRECAUTIONS, Race and CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Losartan Potassium, Reduction in the Risk of Stroke, Race).
Renal Insufficiency:
Losartan: Following oral administration, plasma concentrations and AUCs of losartan and its active metabolite are increased by 50-90% in patients with mild (creatinine clearance of 50 to 74 mL/min) or moderate (creatinine clearance 30 to 49 mL/min) renal insufficiency. In this study, renal clearance was reduced by 55-85% for both losartan and its active metabolite in patients with mild or moderate renal insufficiency. Neither losartan nor its active metabolite can be removed by hemodialysis.
Hydrochlorothiazide: Following oral administration, the AUC for hydrochlorothiazide is increased by 70 and 700% for patients with mild and moderate renal insufficiency, respectively. In this study, renal clearance of hydrochlorothiazide decreased by 45 and 85% in patients with mild and moderate renal impairment, respectively.
The usual regimens of therapy with losartan potassium and hydrochlorothiazide tablets may be followed as long as the patient's creatinine clearance is >30 mL/min. In patients with more severe renal impairment, loop diuretics are preferred to thiazides, so losartan potassium and hydrochlorothiazide tablets are not recommended (See DOSAGE AND ADMINISTRATION).
Hepatic Insufficiency: Following oral administration in patients with mild to moderate alcoholic cirrhosis of the liver, plasma concentrations of losartan and its active metabolite were, respectively, 5 times and about 1.7 times those in young male volunteers. Compared to normal subjects, the total plasma clearance of losartan in patients with hepatic insufficiency was about 50% lower, and the oral bioavailability was about 2 times higher. The lower starting dose of losartan recommended for use in patients with hepatic impairment cannot be given using losartan potassium and hydrochlorothiazide tablets. Its use in such patients as a means of losartan titration is, therefore, not recommended (see DOSAGE AND ADMINISTRATION).
Drug Interactions
Losartan Potassium
Losartan, administered for 12 days, did not affect the pharmacokinetics or pharmacodynamics of a single dose of warfarin. Losartan did not affect the pharmacokinetics of oral or intravenous digoxin. There is no pharmacokinetic interaction between losartan and hydrochlorothiazide. Coadministration of losartan and cimetidine led to an increase of about 18% in AUC of losartan but did not affect the pharmacokinetics of its active metabolite. Coadministration of losartan and phenobarbital led to a reduction of about 20% in the AUC of losartan and that of its active metabolite. A somewhat greater interaction (approximately 40% reduction in the AUC of active metabolite and approximately 30% reduction in the AUC of losartan) has been reported with rifampin. Fluconazole, an inhibitor of cytochrome P450 2C9, decreased the AUC of the active metabolite by approximately 40%, but increased the AUC of losartan by approximately 70% following multiple doses. Conversion of losartan to its active metabolite after intravenous administration is not affected by ketoconazole, an inhibitor of P450 3A4. The AUC of active metabolite following oral losartan was not affected by erythromycin, another inhibitor of P450 3A4, but the AUC of losartan was increased by 30%.
Hydrochlorothiazide
After oral administration of hydrochlorothiazide, diuresis begins within 2 hours, peaks in about 4 hours and lasts about 6 to 12 hours.
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 percent 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.
Losartan Potassium
Hypertension: Losartan inhibits the pressor effect of angiotensin II (as well as angiotensin I) infusions. A dose of 100 mg inhibits the pressor effect by about 85% at peak with 25-40% inhibition persisting for 24 hours. Removal of the negative feedback of angiotensin II causes a 2-to 3-fold rise in plasma renin activity and consequent rise in angiotensin II plasma concentration in hypertensive patients. Losartan does not affect the response to bradykinin, whereas ACE inhibitors increase the response to bradykinin. Aldosterone plasma concentrations fall following losartan administration. In spite of the effect of losartan on aldosterone secretion, very little effect on serum potassium was observed.
In a single-dose study in normal volunteers, losartan had no effects on glomerular filtration rate, renal plasma flow or filtration fraction. In multiple-dose studies in hypertensive patients, there were no notable effects on systemic or renal prostaglandin concentrations, fasting triglycerides, total cholesterol or HDL-cholesterol or fasting glucose concentrations. There was a small uricosuric effect leading to a minimal decrease in serum uric acid (mean decrease <0.4 mg/dL) during chronic oral administration.
The antihypertensive effects of losartan were demonstrated principally in 4 placebo-controlled, 6-to 12-week trials of dosages from 10 to 150 mg per day in patients with baseline diastolic blood pressures of 95-115. The studies allowed comparisons of two doses (50-100 mg/day) as once-daily or twice-daily regimens, comparisons of peak and trough effects, and comparisons of response by gender, age, and race. Three additional studies examined the antihypertensive effects of losartan and hydrochlorothiazide in combination.
The 4 studies of losartan monotherapy included a total of 1075 patients randomized to several doses of losartan and 334 to placebo. The 10 and 25 mg doses produced some effect at peak (6 hours after dosing) but small and inconsistent trough (24 hour) responses. Doses of 50, 100, and 150 mg once daily gave statistically significant systolic/diastolic mean decreases in blood pressure, compared to placebo in the range of 5.5-10.5/3.5-7.5 mmHg, with the 150 mg dose giving no greater effect than 50-100 mg. Twice-daily dosing at 50-100 mg/day gave consistently larger trough responses than once-daily dosing at the same total dose. Peak (6 hour) effects were uniformly, but moderately larger than trough effects, with the trough to peak ratio for systolic and diastolic responses 50-95% and 60-90%, respectively.
Analysis of age, gender, and race subgroups of patients showed that men and women, and patients over and under 65, had generally similar responses. Losartan was effective in reducing blood pressure regardless of race, although the effect was somewhat less in Black patients (usually a low-renin population).
The effect of losartan is substantially present within one week but in some studies the maximal effect occurred in 3-6 weeks. In long-term follow-up studies (without placebo control) the effect of losartan appeared to be maintained for up to a year. There is no apparent rebound effect after abrupt withdrawal of losartan. There was essentially no change in average heart rate in losartan-treated patients in controlled trials.
Reduction in the Risk of Stroke: The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study was a multinational, double-blind study comparing losartan and atenolol in 9193 hypertensive patients with ECG-documented left ventricular hypertrophy. Patients with myocardial infarction or stroke within six months prior to randomization were excluded. Patients were randomized to receive once daily losartan 50 mg or atenolol 50 mg. If goal blood pressure (<140/90 mmHg) was not reached, hydrochlorothiazide (12.5 mg) was added first and, if needed, the dose of losartan or atenolol was then increased to 100 mg once daily. If necessary, other antihypertensive treatments (e.g., increase in dose of hydrochlorothiazide therapy to 25 mg or addition of other diuretic therapy, calcium channel blockers, alpha-blockers, or centrally acting agents, but not ACE inhibitors, angiotensin II antagonists, or beta-blockers) were added to the treatment regimen to reach the goal blood pressure.
In efforts to control blood pressure, the patients in both arms of the LIFE study were coadministered hydrochlorothiazide the majority of time they were on study drug (73.9% and72.4% of days in the losartan and atenolol arms, respectively).
Of the randomized patients, 4963 (54%) were female and 533 (6%) were Black. The mean age was 67 with 5704 (62%) age ≥65. At baseline, 1195 (13%) had diabetes, 1326 (14%) hadisolated systolic hypertension, 1469 (16%) had coronary heart disease, and 728 (8%) had cerebrovascular disease. Baseline mean blood pressure was 174/98 mmHg in both treatment groups. The mean length of follow-up was 4.8 years. At the end of study or at the last visit before a primary endpoint, 77% of the group treated with losartan and 73% of the group treated with atenolol were still taking study medication. Of the patients still taking study medication, the mean doses of losartan and atenolol were both about 80 mg/day, and 15% were taking atenolol or losartan as monotherapy, while 77% were also receiving hydrochlorothiazide (at a mean dose of 20 mg/day in each group). Blood pressure reduction measured at trough was similar for both treatment groups but blood pressure was not measured at any other time of the day. At the end of study or at the last visit before a primary endpoint, the mean blood pressures were 144.1/81.3 mmHg for the group treated with losartan and 145.4/80.9 mmHg for the group treated with atenolol [the difference in SBP of 1.3 mmHg was significant (p<0.001), while the difference of 0.4 mmHg in DBP was not significant (p=0.098)].
The primary endpoint was the first occurrence of cardiovascular death, nonfatal stroke, or nonfatal myocardial infarction. Patients with nonfatal events remained in the trial, so that there was also an examination of the first event of each type even if it was not the first event (e.g., a stroke following an initial myocardial infarction would be counted in the analysis of stroke). Treatment with losartan resulted in a 13% reduction (p=0.021) in risk of the primary endpoint compared to the atenolol group; this difference was primarily the result of an effect on fatal and nonfatal stroke. Treatment with losartan reduced the risk of stroke by 25% relative to atenolol (p=0.001).
For additional details on the LIFE study see the label for losartan potassium tablets.
Race: In the LIFE study, Black patients treated with atenolol were at lower risk of experiencing the primary composite endpoint compared with Black patients treated with losartan. In the subgroup of Black patients (n=533, 6% of the LIFE study patients), there were 29 primary endpoints among 263 patients on atenolol (11%, 26 per 1000 patient-years) and 46 primary endpoints among 270 patients (17%, 42 per 1000 patient-years) on losartan. This finding could not be explained on the basis of differences in the populations other than race or on any imbalances between treatment groups. In addition, blood pressure reductions in both treatment groups were consistent between Black and non-Black patients. Given the difficulty in interpreting subset differences in large trials, it cannot be known whether the observed difference is the result of chance. However, the LIFE study provides no evidence that the benefits of losartan on reducing the risk of cardiovascular events in hypertensive patients with left ventricular hypertrophy apply to Black patients.
Losartan Potassium and Hydrochlorothiazide
The 3 controlled studies of losartan and hydrochlorothiazide included over 1300 patients assessing the antihypertensive efficacy of various doses of losartan (25, 50 and 100 mg) and concomitant hydrochlorothiazide (6.25, 12.5 and 25 mg). A factorial study compared the combination of losartan/hydrochlorothiazide 50/12.5 mg with its components and placebo. The combination of losartan/hydrochlorothiazide 50/12.5 mg resulted in an approximately additive placebo-adjusted systolic/diastolic response (15.5/9.0 mmHg for the combination compared to 8.5/5.0 mmHg for losartan alone and 7.0/3.0 mm Hg for hydrochlorothiazide alone). Another study investigated the dose-response relationship of various doses of hydrochlorothiazide (6.25, 12.5 and 25 mg) or placebo on a background of losartan (50 mg) in patients not adequately controlled (sitting diastolic blood pressure [SiDBP] 93-120 mmHg) on losartan (50 mg) alone. The third study investigated the dose-response relationship of various doses of losartan (25, 50 and 100 mg) or placebo on a background of hydrochlorothiazide (25 mg) in patients not adequately controlled (SiDBP 93-120 mmHg) on hydrochlorothiazide (25 mg) alone. These studies showed an added antihypertensive response at trough (24 hours post-dosing) of hydrochlorothiazide 12.5 or 25 mg added to losartan 50 mg of 5.5/3.5 and 10.0/6.0 mm Hg, respectively. Similarly, there was an added antihypertensive response at trough when losartan 50 or 100 mg was added to hydrochlorothiazide 25 mg of 9.0/5.5 and 12.5/6.5 mmHg, respectively. There was no significant effect on heart rate.
There was no difference in response for men and women or in patients over or under 65 years of age.
Black patients had a larger response to hydrochlorothiazide than non-Black patients and a smaller response to losartan. The overall response to the combination was similar for Black and non-Black patients.
Severe Hypertension (Sitting Diastolic Blood Pressure [SiDBP] ≥110 mm Hg)
The safety and efficacy of losartan potassium and hydrochlorothiazide tablets as initial therapy for severe hypertension (defined as a mean SiDBP≥110 mmHg confirmed on 2 separate occasions off all antihypertensive therapy) was studied in a 6-week double-blind, randomized, multicenter study. Patients were randomized to either losartan and hydrochlorothiazide (50 mg/12.5 mg, once daily) or to losartan (50 mg, once daily) and followed for blood pressure response. Patients were titrated at 2-week intervals if their SiDBP did not reach goal (<90 mmHg). Patients on combination therapy were titrated from losartan 50 mg/hydrochlorothiazide 12.5 mg to losartan 50 mg/hydrochlorothiazide 12.5 mg (sham titration to maintain the blind) to losartan 100 mg/hydrochlorothiazide 25 mg. Patients on monotherapy were titrated from losartan 50 mg to losartan 100 mg to losartan 150 mg, as needed. The primary endpoint was a comparison at 4 weeks of patients who achieved goal diastolic blood pressure (trough SiDBP <90 mmHg).
The study enrolled 585 patients, including 264 (45%) females, 124 (21%) blacks, and 21 (4%) ≥65 years of age. The mean blood pressure at baseline for the total population was 171/113 mmHg. The mean age was 53 years. After 4 weeks of therapy, the mean SiDBP was 3.1 mmHg lower and the mean SiSBP was 5.6 mmHg lower in the group treated with losartan potassium and hydrochlorothiazide tablets. As a result, a greater proportion of the patients on losartan potassium and hydrochlorothiazide tablets reached the target diastolic blood pressure (17.6% for losartan potassium and hydrochlorothiazide tablets, 9.4% for losartan; p=0.006). Similar trends were seen when the patients were grouped according to gender, race or age (<, ≥ 65).
After 6 weeks of therapy, more patients who received the combination regimen reached target diastolic blood pressure than those who received the monotherapy regimen (29.8% versus 12.5%).
During the study period, there were no reported cases of syncope in either treatment group. There were 2 (0.6%) and 0 (0.0%) cases of hypotension reported in the group treated with losartan potassium and hydrochlorothiazide tablets and the group treated with losartan, respectively. The overall pattern of adverse events reported for patients treated with losartan potassium and hydrochlorothiazide tablets as initial therapy was similar to the adverse event profile for patients treated with losartan as initial therapy. For information on the specific adverse events observed during the study period, see ADVERSE REACTIONS, Severe Hypertension.
Hypertensive Patients with Left Ventricular Hypertrophy
Losartan potassium and hydrochlorothiazide tablets are indicated to reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy, but there is evidence that this benefit does not apply to Black patients (See PRECAUTIONS, Race, CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Losartan Potassium, Reduction in the Risk of Stroke, Race, and DOSAGE AND ADMINISTRATION).
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.
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, losartan potassium and hydrochlorothiazide tablets should be discontinued unless it is 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.
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.
Hypersensitivity: Angioedema. See ADVERSE REACTIONS, Post-Marketing Experience.
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. Because losartan decreases uric acid, losartan in combination with hydrochlorothiazide attenuates the diuretic-induced hyperuricemia.
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 postsympathectomy 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.
In studies of ACE inhibitors in patients with unilateral or bilateral renal artery stenosis, increases in serum creatinine or BUN have been reported. Similar effects have been reported with losartan; in some patients, these effects were reversible upon discontinuation of therapy.
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.
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.
Symptomatic Hypotension: A patient receiving losartan potassium and 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, losartan potassium and hydrochlorothiazide tablets 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.
Potassium Supplements: A patient receiving losartan potassium and hydrochlorothiazide tablets should be told not to use potassium supplements or salt substitutes containing potassium without consulting the prescribing physician (see PRECAUTIONS, Drug Interactions, Losartan Potassium).
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, or glycyrrhizin (found in liquorice) – 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.
Losartan potassium and hydrochlorothiazide when tested at a weight ratio of 4:1 was negative in the Ames microbial mutagenesis assay and the V-79 Chinese hamster lung cell mutagenesis assay. In addition, there was no evidence of direct genotoxicity in the in vitro alkaline elution assay in rat hepatocytes and in vitro chromosomal aberration assay in Chinese hamster ovary cells at noncytotoxic concentrations.
Losartan potassium, coadministered with hydrochlorothiazide, had no effect on the fertility or mating behavior of male rats at dosages up to 135 mg/kg/day of losartan and 33.75 mg/kg/day of hydrochlorothiazide. These dosages have been shown to provide respective systemic exposures (AUCs) for losartan, its active metabolite and hydrochlorothiazide that are approximately 60, 60 and 30 times greater than those achieved in humans with 100 mg of losartan potassium in combination with 25 mg of hydrochlorothiazide. In female rats, however, the coadministration of doses as low as 10 mg/kg/day of losartan and 2.5 mg/kg/day of hydrochlorothiazide was associated with slight but statistically significant decreases in fecundity and fertility indices. AUC values for losartan, its active metabolite andhydrochlorothiazide, extrapolated from data obtained with losartan administered to rats at a dose of 50 mg/kg/day in combination with 12.5 mg/kg/day of hydrochlorothiazide, were approximately 6, 2, and 2 times greater than those achieved in humans with 100 mg of losartan in combination with 25 mg of hydrochlorothiazide.
Losartan potassium was negative in the microbial mutagenesis and V-79 mammalian cell mutagenesis assays and in the in vitro alkaline elution and in vitro and in vivo chromosomal aberration assays. In addition, the active metabolite showed no evidence of genotoxicity in the microbial mutagenesis, in vitro alkaline elution, and in vitro chromosomal aberration assays.
It is not known whether losartan is excreted in human milk, but significant levels of losartan and its active metabolite were shown to be present in rat milk. 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.
In a controlled clinical study for the reduction in the combined risk of cardiovascular death, stroke and myocardial infarction in hypertensive patients with left ventricular hypertrophy, 2857 patients (62%) were 65 years and over, while 808 patients (18%) were 75 years and over. In an effort to control blood pressure in this study, patients were coadministered losartan and hydrochlorothiazide 74% of the total time they were on study drug. No overall differences in effectiveness were observed between these patients and younger patients. Adverse events were somewhat more frequent in the elderly compared to non-elderly patients for both the losartan and hydrochlorothiazide and the control groups (see CLINICAL PHARMACOLOGY, Special Populations).
Losartan potassium and hydrochlorothiazide has been evaluated for safety in 858 patients treated for essential hypertension and 3889 patients treated for hypertension and left ventricular hypertrophy. In clinical trials with losartan potassium and hydrochlorothiazide, no adverse experiences peculiar to this combination have been observed. Adverse experiences have been limited to those that were reported previously with losartan potassium and/or hydrochlorothiazide. The overall incidence of adverse experiences reported with the combination was comparable to placebo.
In general, treatment with losartan potassium and hydrochlorothiazide 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 therapy due to clinical adverse experiences was required in only 2.8% and 2.3% of patients treated with the combination and placebo, respectively.
|
Losartan Potassium and Hydrochlorothiazide (n=858) | Placebo (n=173) |
Body as a Whole Abdominal pain Edema/swelling |
1.2 1.3 |
0.6 1.2 |
Cardiovascular Palpitation |
1.4 |
0.0 |
Musculoskeletal Back pain |
2.1 |
0.6 |
Nervous/Psychiatric Dizziness |
5.7 |
2.9 |
Respiratory Cough Sinusitis Upper respiratory infection |
2.6 1.2 6.1 |
2.3 0.6 4.6 |
Skin Rash |
1.4 |
0.0 |
Adverse events occurred at about the same rates in men and women. Adverse events were somewhat more frequent in the elderly compared to non-elderly patients and somewhat more frequent in Blacks compared to non-Blacks for both the losartan and hydrochlorothiazide and the control groups.
A patient with known hypersensitivity to aspirin and penicillin, when treated with losartan potassium, was withdrawn from study due to swelling of the lips and eyelids and facial rash, reported as angioedema, which returned to normal 5 days after therapy was discontinued.
Study 1† Cough |
HCTZ 25% |
Losartan 17% |
Lisinopril 69% |
Study 2†† Cough |
Placebo 35% |
Losartan 29% |
Lisinopril 62% |
Limited data are available in regard to over dosage in humans. The most likely manifestation of overdosage would be hypotension and tachycardia; bradycardia could occur from parasympathetic (vagal) stimulation. If symptomatic hypotension should occur, supportive treatment should be instituted.
Neither losartan nor its active metabolite can be removed by hemodialysis.
Hypertension
Dosing must be individualized. The usual starting dose of losartan is 50 mg once daily, with 25 mg recommended for patients with intravascular volume depletion (e.g., patients treated with diuretics) (see WARNINGS, Hypotension Volume-Depleted Patients) and patients with a history of hepatic impairment (see WARNINGS, Impaired Hepatic Function). Losartan can be administered once or twice daily at total daily doses of 25 to 100 mg. If the antihypertensive effect measured at trough using once-a-day dosing is inadequate, a twice-a-day regimen at the same total daily dose or an increase in dose may give a more satisfactory response.
Hydrochlorothiazide is effective in doses of 12.5 to 50 mg once daily and can be given at doses of 12.5 to 25 mg as losartan potassium and hydrochlorothiazide tablets.
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 WARNINGS) of losartan are generally rare and apparently independent of dose; those of hydrochlorothiazide are a mixture of dose-dependent (primarily hypokalemia) and dose-independent phenomena (e.g., pancreatitis), the former much more common than the latter. Therapy with any combination of losartan and hydrochlorothiazide will be associated with both sets of dose-independent side effects.
Replacement Therapy: The combination may be substituted for the titrated components.
Dose Titration by Clinical Effect: A patient whose blood pressure is not adequately controlled with losartan monotherapy (see above) or hydrochlorothiazide alone, may be switched to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg (losartan 50 mg/hydrochlorothiazide 12.5 mg) once daily. If blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg (losartan 100 mg/hydrochlorothiazide 25 mg) once daily. A patient whose blood pressure is not adequately controlled with losartan 100 mg monotherapy (see above) may be switched to losartan potassium and hydrochlorothiazide tablets 100 mg/12.5 mg once daily. If blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg (losartan 100 mg/hydrochlorothiazide 25 mg) once daily.
A patient whose blood pressure is inadequately controlled by 25 mg once daily of hydrochlorothiazide, or is controlled but who experiences hypokalemia with this regimen, may be switched to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg (losartan 50 mg/hydrochlorothiazide 12.5 mg) once daily, reducing the dose of hydrochlorothiazide without reducing the overall expected antihypertensive response. The clinical response to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg should be subsequently evaluated, and if blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg (losartan 100 mg/ hydrochlorothiazide 25 mg) once daily.
The usual dose of losartan potassium and hydrochlorothiazide is one tablet of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily. More than two tablets of losartan potassium and hydrochlorothiazide 50 mf/12.5 mg once daily or more than one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily is not recommended. The maximal antihypertensive effect is attained about 3 weeks after initiation of therapy.
Use in Patients with Renal Impairment: The usual regimens of therapy with losartan potassium and hydrochlorothiazide tablets may be followed as long as the patient's creatinine clearance is >30 mL/min. In patients with more severe renal impairment, loop diuretics are preferred to thiazides, so losartan potassium and hydrochlorothiazide tablet is not recommended.
Patients with Hepatic Impairment: Losartan potassium and hydrochlorothiazide tablet is not recommended for titration in patients with hepatic impairment (see WARNINGS, Impaired Hepatic Function) because the appropriate 25 mg starting dose of losartan cannot be given.
Severe Hypertension
The starting dose of losartan potassium and hydrochlorothiazide tablets for initial treatment of severe hypertension is one tablet of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects). For patients who do not respond adequately to losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg after 2 to 4 weeks of therapy, the dosage may be increased to one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. The maximum dose is one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. Losartan potassium and hydrochlorothiazide tablets are not recommended as initial therapy in patients with hepatic impairment (see WARNINGS, Impaired Hepatic Function) because the appropriate 25 mg starting dose of losartan cannot be given. It is also not recommended for use as initial therapy in patients with intravascular volume depletion (e.g., patients treated with diuretics, see WARNINGS, Hypotension Volume-Depleted Patients).
Hypertensive Patients with Left Ventricular Hypertrophy
Treatment should be initiated with losartan potassium 50 mg once daily. Hydrochlorothiazide 12.5 mg should be added or losartan potassium and hydrochlorothiazide tablets 50 mg/12.5 mg substituted if the blood pressure reduction is inadequate. If additional blood pressure reduction is needed, losartan potassium 100 mg and hydrochlorothiazide 12.5 mg or losartan potassium and hydrochlorothiazide tablets 100 mg /12.5 mg may be substituted, followed by losartan potassium 100 mg and hydrochlorothiazide 25 mg or losartan potassium and hydrochlorothiazide tablets 100 mg/25 mg. For further blood pressure reduction other antihypertensives should be added (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Losartan Potassium, Reduction in the Risk of Stroke).
Losartan potassium and hydrochlorothiazide tablets may be administered with other antihypertensive agents.
Losartan potassium and hydrochlorothiazide tablets may be administered with or without food.
Left Ventricular Hypertrophy (LVH) is an enlargement of the walls of the left chamber of the heart (the heart’s main pumping chamber). LVH can happen from several things. High blood pressure is the most common cause of LVH.
Know the medicines you take. Keep a list of your medicines and show it to your doctor and pharmacist when you get a new medicine.
How should I take losartan potassium and hydrochlorothiazide tablets?
The most common side effects of losartan potassium and hydrochlorothiazide tablets in people with high blood pressure are:
Tell your doctor if you get any side effect that bothers you or that won't go away. This is not a complete list of side effects. For a complete list, ask your doctor or pharmacist.
How should I store losartan potassium and hydrochlorothiazide tablets?
This leaflet summarizes the most important information about losartan potassium and hydrochlorothiazide tablets. If you would like more information, talk with your doctor. You can ask your pharmacist or doctor for information that is written for health professionals.
What are the ingredients in losartan potassium and hydrochlorothiazide tablets?
LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE
losartan potassium and hydrochlorothiazide tablet, film coated |
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LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE
losartan potassium and hydrochlorothiazide tablet, film coated |
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LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE
losartan potassium and hydrochlorothiazide tablet, film coated |
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Labeler - Qualitest Pharmaceuticals (011103059) |
Registrant - Alembic Pharmaceuticals Limited (650051741) |
Establishment | |||
Name | Address | ID/FEI | Business Operations |
Alembic Pharmaceuticals Limited (Formulation Division) | 918592874 | MANUFACTURE(0603-4228, 0603-4229, 0603-4230) |