1. Name Of The Medicinal Product
Cozaar Comp 50 mg/12.5 mg film-coated tablets
Cozaar Comp 100 mg/12.5 mg film-coated tablets
Cozaar Comp 100 mg/25 mg film-coated tablets
2. Qualitative And Quantitative Composition
Cozaar Comp 50 mg/12.5 mg
Each tablet contains 50 mg of losartan potassium and 12.5 mg of hydrochlorothiazide (HCTZ).
Cozaar Comp 100 mg/12.5 mg
Each tablet contains 100 mg of losartan potassium and 12.5 mg of hydrochlorothiazide (HCTZ).
Cozaar Comp 100 mg/25 mg
Each tablet contains 100 mg of losartan potassium and 25 mg of hydrochlorothiazide (HCTZ).
Cozaar Comp 50 mg/12.5 mg: each tablet contains 63.13 mg lactose monohydrate.
Cozaar Comp 100 mg/12.5 mg: each tablet contains 88.40 mg lactose monohydrate.
Cozaar Comp 100 mg/25 mg: each tablet contains 126.26 mg lactose monohydrate.
For a full list of excipients, see section 6.1.
3. Pharmaceutical Form
Film coated tablets
Cozaar Comp 50 mg/12.5 mg
Yellow, oval film-coated tablets marked 717 on one side and plain or scored on the other.
The scoreline is only to facilitate breaking for ease of swallowing and not to divide into equal doses.
Cozaar Comp 100 mg/12.5 mg
White, oval film-coated tablets marked 745 on one side and plain on the other.
Cozaar Comp 100 mg/25 mg
Light yellow, oval film-coated tablets marked 747 on one side and plain on the other.
4. Clinical Particulars
4.1 Therapeutic Indications
Cozaar Comp is indicated for the treatment of essential hypertension in patients whose blood pressure is not adequately controlled on losartan or hydrochlorothiazide alone.
4.2 Posology And Method Of Administration
Cozaar Comp may be administered with other antihypertensive agents.
Cozaar Comp tablets should be swallowed with a glass of water.
Cozaar Comp may be administered with or without food.
Hypertension
Losartan and hydrochlorothiazide is not for use as initial therapy, but in patients whose blood pressure is not adequately controlled by losartan potassium or hydrochlorothiazide alone.
Dose titration with the individual components (losartan and hydrochlorothiazide) is recommended.
When clinically appropriate, direct change from monotherapy to the fixed combination may be considered in patients whose blood pressure is not adequately controlled.
The usual maintenance dose of Cozaar Comp is one tablet of Cozaar Comp 50 mg/12.5 mg (losartan 50 mg/HCTZ 12.5 mg) once daily. For patients who do not respond adequately to Cozaar Comp 50 mg/12.5 mg, the dosage may be increased to one tablet of Cozaar Comp 100 mg/25 mg (losartan 100 mg/ HCTZ 25 mg) once daily. The maximum dose is one tablet of Cozaar Comp 100 mg/25 mg once daily. In general, the antihypertensive effect is attained within three to four weeks after initiation of therapy. Cozaar Comp 100/12.5 (losartan 100 mg/ HCTZ 12.5 mg) is available for those patients titrated to 100 mg of Cozaar who require additional blood pressure control.
Use in patients with renal impairment and haemodialysis patients
No initial dosage adjustment is necessary in patients with moderate renal impairment (i.e. creatinine clearance 30-50 ml/min). Losartan and hydrochlorothiazide tablets are not recommended for haemodialysis patients. Losartan/HCTZ tablets must not be used in patients with severe renal impairment (i.e. creatinine clearance <30 ml/min) (see section 4.3).
Use in patients with intravascular volume depletion
Volume and/or sodium depletion should be corrected prior to administration of losartan/HCTZ tablets.
Use in patients with hepatic impairment
Losartan/HCTZ is contraindicated in patients with severe hepatic impairment (see section 4.3).
Use in the elderly
Dosage adjustment is not usually necessary for the elderly.
Use in children and adolescents (< 18 years)
There is no experience in children and adolescents. Therefore, losartan/hydrochlorothiazide should not be administered to children and adolescents.
4.3 Contraindications
• Hypersensitivity to losartan, sulphonamide-derived substances (as hydrochlorothiazide) or to any of the excipients
• Therapy resistant hypokalaemia or hypercalcaemia
• Severe hepatic impairment; cholestasis and biliary obstructive disorders
• Refractory hyponatraemia
• Symtomatic hyperuricaemia/gout
• 2nd and 3rd trimester of pregnancy (see section 4.4 and 4.6)
• Severe renal impairment (i.e. creatinine clearance <30 ml/min)
• Anuria.
4.4 Special Warnings And Precautions For Use
Losartan
Angiooedema
Patients with a history of angiooedema (swelling of the face, lips, throat, and/or tongue) should be closely monitored (see section 4.8).
Hypotension and Intravascular volume depletion
Symptomatic hypotension, especially after the first dose, may occur in patients who are volume- and/or sodium-depleted by vigorous diuretic therapy, dietary salt restriction, diarrhoea or vomiting. Such conditions should be corrected before the administration of Cozaar Comp tablets (see sections 4.2. and 4.3).
Electrolyte imbalances
Electrolyte imbalances are common in patients with renal impairment, with or without diabetes, and should be addressed. Therefore, the plasma concentrations of potassium and creatinine clearance values should be closely monitored; especially patients with heart failure and a creatinine clearance between 30-50 ml/min should be closely monitored.
The concomitant use of potassium sparing diuretics, potassium supplements and potassium containing salt substitutes with losartan/hydrochlorothiazide is not recommended (see section 4.5).
Liver function impairment
Based on pharmacokinetic data which demonstrate significantly increased plasma concentrations of losartan in cirrhotic patients, Cozaar Comp should be used with caution in patients with a history of mild to moderate hepatic impairment. There is no therapeutic experience with losartan in patients with severe hepatic impairment. Therefore Cozaar Comp is contraindicated in patients with severe hepatic impairment (see sections 4.2, 4.3 and 5.2).
Renal function impairment
As a consequence of inhibiting the renin-angiotensin-aldosterone system, changes in renal function, including renal failure, have been reported (in particular, in patients whose renal function is dependent on the renin-angiotensin-aldosterone system, such as those with severe cardiac insufficiency or pre-existing renal dysfunction).
As with other drugs that affect the renin-angiotensin-aldosterone system, increases in blood urea and serum creatinine have also been reported in patients with bilateral renal artery stenosis or stenosis of the artery to a solitary kidney; these changes in renal function may be reversible upon discontinuation of therapy. Losartan should be used with caution in patients with bilateral renal artery stenosis or stenosis of the artery to a solitary kidney.
Renal transplantation
There is no experience in patients with recent kidney transplantation.
Primary hyperaldosteronism
Patients with primary aldosteronism generally will not respond to antihypertensive drugs acting through inhibition of the renin-angiotensin system. Therefore, the use of Cozaar Comp tablets is not recommended.
Coronary heart disease and cerebrovascular disease:
As with any antihypertensive agents, excessive blood pressure decrease in patients with ischaemic cardiovascular and cerebrovascular disease could result in a myocardial infarction or stroke.
Heart failure:
In patients with heart failure, with or without renal impairment, there is - as with other drugs acting on the renin-angiotensin system - a risk of severe arterial hypotension, and (often acute) renal impairment.
Aortic and mitral valve stenosis, obstructive hypertrophic cardiomyophathy
As with other vasodilators, special caution is indicated in patients suffering from aortic or mitral stenosis, or obstructive hypertrophic cardiomyopathy.
Ethnic differences
As observed for angiotensin converting enzyme inhibitors, losartan and the other angiotensin antagonists are apparently less effective in lowering blood pressure in black people than in non-blacks, possibly because of higher prevalence of low-renin states in the black hypertensive population.
Pregnancy
AIIRAs should not be initiated during pregnancy. Unless continued AIIAR therapy is considered essential, patients planning pregnancy should be changed to alternative anti-hypertensive treatments which have an established safety profile for use in pregnancy. When pregnancy is diagnosed, treatment with AIIRAs should be stopped immediately, and, if appropriate, alternative therapy should be started (see sections 4.3 and 4.6).
Hydrochlorothiazide
Hypotension and electrolyte/fluid imbalance
As with all antihypertensive therapy, symptomatic hypotension may occur in some patients. Patients should be observed for clinical signs of fluid or electrolyte imbalance, e.g., volume depletion, hyponatremia, hypochloremic alkalosis, hypomagnesemia or hypokalemia which may occur during intercurrent diarrhea or vomiting. Periodic determination of serum electrolytes should be performed at appropriate intervals in such patients. Dilutional hyponatraemia may occur in oedematous patients in hot weather.
Metabolic and endocrine effects
Thiazide therapy may impair glucose tolerance. Dosage adjustment of antidiabetic agents, including insulin, may be required (see section 4.5). Latent diabetes mellitus may become manifest during thiazide therapy.
Thiazides may decrease urinary calcium excretion and may cause intermittent and slight elevation of serum calcium. 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.
Thiazide therapy may precipitate hyperuricemia and/or gout in certain patients. Because losartan decreases uric acid, losartan in combination with hydrochlorothiazide attenuates the diuretic-induced hyperuricemia.
Hepatic impairment
Thiazides should be used with caution in patients with impaired hepatic function or progressive liver disease, as it may cause intrahepatic cholestasis, and since minor alterations of fluid and electrolyte balance may precipitate hepatic coma.
Cozaar Comp is contraindicated for patients with severe hepatic impairment (see section 4.3 and 5.2).
Other
In patients receiving thiazides, hypersensitivity reactions may occur with or without a history of allergy or bronchial asthma. Exacerbation or activation of systemic lupus erythematosus has been reported with the use of thiazides.
Excipient
This medicinal product contains lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction
Losartan
Rifampicin and fluconazole have been reported to reduce levels of active metabolite. The clinical consequences of these interactions have not been evaluated.
As with other drugs that block angiotensin II or its effects, concomitant use of potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, or salt substitutes containing potassium may lead to increases in serum potassium. Co-medication is not advisable.
As with other medicines which affect the excretion of sodium, lithium excretion may be reduced. Therefore, serum lithium levels should be monitored carefully if lithium salts are to be co-administered with angiotensin II receptor antagonists.
When angiotensin II antagonists are administered simultaneously with NSAIDs (i.e. selective COX-2 inhibitors, acetylsalicylic acid at anti-inflammatory doses) and non-selective NSAIDs, attenuation of the antihypertensive effect may occur. Concomitant use of angiotensin II antagonists or diuretics and NSAIDs may lead to an increased risk of worsening of renal function, including possible acute renal failure, and an increase in serum potassium, especially in patients with poor pre-existing renal function. The combination should be administered with caution, especially in the elderly. Patients should be adequately hydrated and consideration should be given to monitoring renal function after initiation of concomitant therapy, and periodically thereafter.
In some patients with compromised renal function who are being treated with non-steroidal anti-inflammatory drugs, including selective cyclooxygenase-2 inhibitors, the co-administration of angiotensin II receptor antagonists may result in a further deterioration of renal function. These effects are usually reversible.
Other substances inducing hypotension like tricyclic antidepressants, antipsychotics, baclofene, amifostine: Concomitant use with these drugs that lower blood pressure, as main or side-effect, may increase the risk of hypotension.
Hydrochlorothiazide
When given concurrently, the following drugs may interact with thiazide diuretics:
Alcohol, barbiturates, narcotics or antidepressants:
Potentiation of orthostatic hypotension may occur.
Antidiabetic drugs (oral agents and insulin):
The treatment with a thiazide may influence the glucose tolerance. Dosage adjustment of the antidiabetic drug may be required. Metformin should be used with caution because of the risk of lactic acidosis induced by possible functional renal failure linked to hydrochlorothiazide.
Other antihypertensive drugs
Additive effect.
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., adrenaline)
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
Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity; concomitant use is not recommended.
Medicinal products used in the treatment of gout (probenecid, sulfinpyrazone and allopurinol)
Dosage adjustment of uricosuric medicinal products may be necessary since hydrochlorothiazide may raise the level of serum uric acid. Increase in dosage of probenecid or sulfinpyrazone may be necessary. Coadministration of a thiazide may increase the incidence of hypersensitivity reactions to allopurinol.
Anticholinergic agents (e.g. atropine, biperiden)
Increase of the bioavailability to thiazide-type diuretics by decreasing gastrointestinal motility and stomach emptying rate.
Cytotoxic agents (eg cyclophosphamide, methotrexate)
Thiazides may reduce the renal excretion of cytotoxic medicinal products and potentiate their myelosuppressive effects.
Salicylates
In case of high dosages of salicylates hydrochlorothiazide may enhance the toxic effect of the salicylates on the central nervous system.
Methyldopa
There have been isolated reports of haemolytic anaemia occurring with concomitant use of hydrochlorothiazide and methyldopa.
Ciclosporin
Concomitant treatment with ciclosporin may increase the risk of hyperuricaemia and gout-type complications.
Digitalis glycosides
Thiazide-induced hypokalaemia or hypomagnesaemia may favour the onset of digitalis-induced cardiac arrhythmias.
Medicinal products affected by serum potassium disturbances
Periodic monitoring of serum potassium and ECG is recommended when losartan/hydrochlorothiazide is administered with medicinal products affected by serum potassium disturbances (e.g. digitalis glycosides and antiarrhythmics) and with the following torsades de pointes (ventricular tachycardia)-inducing medicinal products (including some antiarrhythmics), hypokalaemia being a predisposing factor to torsades de pointes (ventricular tachycardia):
• Class Ia antiarrythmics (eg quinidine, hydroquinidine, disopyramide).
• Class III antiarrythmics (eg amiodarone, sotalol, dofetilide, ibutilide).
• Some antipsychotics (eg thioridazine, chlorpromazine, levomepromazine, trifluoperazine, cyamemazine, sulpiride, sultopride, amisulpride, tiapride, pimozide, haloperidol, droperidol).
• Others (eg bepridil, cisapride, diphemanil, erythromycin IV, halofantrin, mizolastin, pentamidine, terfenadine, vincamine IV).
Calcium salts
Thiazide diuretics may increase serum calcium levels due to decreased excretion. If calcium supplements must be prescribed, serum calcium levels should be monitored and calcium dosage should be adjusted accordingly.
Laboratory Test Interactions
Because of their effects on calcium metabolism, thiazides may interfere with tests for parathyroid function (see section 4.4).
Carbamazepine
Risk of symptomatic hyponatremia. Clinical and biological monitoring is required.
Iodine Contrast Media
In case of diuretic-induced dehydration, there is an increased risk of acute renal failure, especially with high doses of the iodine product.
Patients should be rehydrated before the administration.
Amphotericin B (parenteral), corticosteroids, ACTH or stimulant laxatives
Hydrochlorothiazide may intensify electrolyte imbalance, particularly hypokalaemia.
4.6 Pregnancy And Lactation
Pregnancy
The use of AIIRAs is not recommended during the first trimester of pregnancy (see section 4.4). The use of AIIRAs is contra-indicated during the 2nd and 3rd trimester of pregnancy (see section 4.3 and 4.4).
Epidemiological evidence regarding the risk of teratogenicity following exposure to ACE inhibitors during the first trimester of pregnancy has not been conclusive; however a small increase in risk cannot be excluded. Whilst there is no controlled epidemiological data on the risk with Angiotensin II Receptor Inhibitors (AIIRAs), similar risks may exist for this class of drugs. Unless continued AIIRA therapy is considered essential, patients planning pregnancy should be changed to alternative anti-hypertensive treatments which have an established safety profile for use in pregnancy. When pregnancy is diagnosed, treatment with AIIRAs should be stopped immediately and, if appropriate, alternative therapy should be started.
Exposure to AIIRA therapy during the second and third trimesters is known to induce human fetotoxicity (decreased renal function, oligohydramnios, skull ossification retardation) and neonatal toxicity (renal failure, hypotension, hyperkalaemia) (see section 5.3).
Should exposure to AIIRAs have occurred from the second trimester of pregnancy, ultrasound check of renal function and skull is recommended.
Infants whose mothers have taken AIIRAs should be closely observed for hypotension (see sections 4.3 and 4.4).
There is limited experience with hydrochlorothiazide during pregnancy, especially during the first trimester. Animal studies are insufficient.
Hydrochlorothiazide crosses the placenta. Based on the pharmacological mechanism of action of hydrochlorothiazide, its use during second and third trimesters may compromise foeto-placental perfusion and may cause foetal and neonatal effects like icterus, disturbance of electrolyte balance and thrombocytopenia.
Hydrochlorothiazide should not be used for gestational oedema, gestational hypertension or preeclampsia due to the risk of decreased plasma volume and placental hypoperfusion, without a beneficial effect on the course of the disease.
Hydrochlorothiazide should not be used for essential hypertension in pregnant women, except in rare situations where no other alternative treatment could be used.
Lactation
No information is available regarding the use of Cozaar Comp during breastfeeding. Hydrochlorothiazide is excreted in human milk. Therefore, the use of Cozaar Comp during breastfeeding is not recommended. Alternative treatments with better established safety profiles during breastfeeding are preferable, especially while nursing a newborn or preterm infant.
4.7 Effects On Ability To Drive And Use Machines
No studies on the reactions on the ability to drive and use machines have been performed. However, when driving vehicles or operating machinery it must be borne in mind that dizziness or drowsiness may occasionally occur when taking antihypertensive therapy, in particular during initiation of treatment or when the dose is increased.
4.8 Undesirable Effects
The adverse reactions below are classified where appropriate by system organ class and frequency according to the following convention:
Very common:
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Common:
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Uncommon:
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Rare:
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Very rare:
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Not known:
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(cannot be estimated from the available data)
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In clinical trials with losartan potassium salt and hydrochlorothiazide, no adverse reactions peculiar to this combination of substances were observed. The adverse reactions were restricted to those which were formerly observed with losartan potassium salt and/or hydrochlorothiazide.
In controlled clinical trials for essential hypertension, dizziness was the only adverse reaction reported as substance-related that occurred with an incidence greater than placebo in 1% or more of patients treated with losartan and hydrochlorothiazide.
Next to these effects, there are further adverse reactions reported after the introduction of the product to the market as follows:
Hepato-biliary disorders
rare: Hepatitis
Investigations
rare: Hyperkalaemia, elevation of ALT
Additional adverse reactions that have been seen with one of the individual components and may be potential adverse reactions with losartan potassium/hydrochlorothiazide are the following:
Losartan
Blood and lymphatic system disorders
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uncommon:
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Anaemia, Henoch-Schönlein purpura, ecchymosis, haemolysis
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Immune system disorders
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rare:
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Anaphylactic reactions, angioedema, urticaria
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Metabolism and nutrition disorders
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uncommon:
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Anorexia, gout
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Psychiatric disorders
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common:
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Insomnia
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uncommon:
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Anxiety, anxiety disorder, panic disorder, confusion, depression, abnormal dreams, sleep disorder, somnolence, memory impairment
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Nervous system disorders
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common:
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Headache, dizziness
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uncommon:
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Nervousness, paraesthesia, peripheral neuropathy, tremor, migraine, syncope
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Eye disorders
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uncommon:
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Blurred vision, burning/stinging in the eye, conjunctivitis, decrease in visual acuity
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Ear and labyrinth disorders
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uncommon:
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Vertigo, tinnitus
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Cardiac disorders
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uncommon:
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Hypotension, orthostatic hypotension, sternalgia, angina pectoris, grade II-AV block, cerebrovascular event, myocardial infarction, palpitation, arrhythmias (atrial fibrillations, sinus bradycardia, tachycardia, ventricular tachycardia, ventricular fibrillation)
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Vascular disorders
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uncommon:
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Vasculitis
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Respiratory, thoracic and mediastinal disorders
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common:
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Cough, upper respiratory infection, nasal congestion, sinusitis, sinus disorder
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uncommon:
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Pharyngeal discomfort, pharyngitis, laryngitis, dyspnoea, bronchitis, epistaxis, rhinitis, respiratory congestion
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Gastrointestinal disorders
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common:
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Abdominal pain, nausea, diarrhoea, dyspepsia
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uncommon:
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Constipation, dental pain, dry mouth, flatulence, gastritis, vomiting
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Hepato-biliary disorders
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not known:
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Liver function abnormalities
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Skin and subcutaneous tissue disorders
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uncommon:
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Alopecia, dermatitis, dry skin, erythema, flushing, photosensitivity, pruritus, rash, urticaria, sweating
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Musculoskeletal and connective tissue disorders
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common:
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Muscle cramp, back pain, leg pain, myalgia
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uncommon:
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Arm pain, joint swelling, knee pain, musculoskeletal pain, shoulder pain, stiffness, arthralgia, arthritis, coxalgia, fibromyalgia, muscle weakness
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Renal and urinary disorders
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uncommon:
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Nocturia, urinary frequency, urinary tract infection
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Reproductive system and breast disorders
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uncommon:
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Decreased libido, impotence
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General disorders and administration site conditions
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common:
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Asthenia, fatigue, chest pain
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uncommon:
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Facial oedema, fever
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Investigations
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common:
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Hyperkalaemia, mild reduction of haematocrit and haemoglobin
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uncommon:
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Mild increase in urea and creatinine serum levels
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very rare:
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Increase in hepatic enzymes and bilirubin.
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Hydrochlorothiazide
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Blood and lymphatic system disorders
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uncommon:
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Agranulocytosis, aplastic anaemia, haemolytic anaemia, leukopenia, purpura, thrombocytopenia
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Immune system disorders
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rare:
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Anaphylactic reaction
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Metabolism and nutrition disorders
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uncommon:
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Anorexia, hyperglycaemia, hyperuricaemia, hypokalaemia, hyponatraemia
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Psychiatric disorders
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uncommon:
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Insomnia
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Nervous system disorders
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common:
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Cephalalgia
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Eye disorders
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uncommon:
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Transient blurred vision, xanthopsia
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Vascular disorders
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uncommon:
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Necrotising angiitis (vasculitis, cutaneous vasculitis)
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Respiratory, thoracic and mediastinal disorders
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uncommon:
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Respiratory distress including pneumonitis and pulmonary oedema
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Gastrointestinal disorders
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uncommon:
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Sialoadenitis, spasms, stomach irritation, nausea, vomiting, diarrhoea, constipation
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Hepato-biliary disorders
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uncommon:
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Icterus (intrahepatic cholestatis), pancreatitis
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Skin and subcutaneous tissue disorders
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uncommon:
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Photosensitivity, urticaria, toxic epidermal necrolysis
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Musculoskeletal and connective tissue disorders
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uncommon:
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Muscle cramps
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Renal and urinary disorders
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uncommon:
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Glycosuria, interstitial nephritis, renal dysfunction, renal failure
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General disorders and administration site conditions
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uncommon:
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Fever, dizziness
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4.9 Overdose
No specific information is available on the treatment of overdose with Cozaar Comp. Treatment is symptomatic and supportive. Therapy with Cozaar Comp should be discontinued and the patient observed closely. Suggested measures include induction of emesis if ingestion is recent, and correction of dehydration, electrolyte imbalance, hepatic coma and hypotension by established procedures.
Losartan
Limited data are available in regard to overdose in humans. The most likely manifestation of overdose 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 the active metabolite can be removed by hemodialysis.
Hydrochlorothiazide
The most common signs and symptoms observed 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.
5. Pharmacological Properties
5.1 Pharmacodynamic Properties
Pharmacotherapeutic group: Angiotensin II antagonists and diuretics
ATC code: C09DA01
Losartan-Hydrochlorothiazide
The components of Cozaar Comp have been shown to have an additive effect on blood pressure reduction, reducing blood pressure to a greater degree than either component alone. This effect is thought to be a result of the complimentary actions of both components. Further, as a result of its diuretic effect, hydrochlorothiazide increases plasma renin activity, increases aldosterone secretion, decreases serum potassium, and increases the levels of angiotensin II. Administration of losartan blocks all the physiologically relevant actions of angiotensin II and through inhibition of aldosterone could tend to attenuate the potassium loss associated with the diuretic.
Losartan has been shown to have a mild and transient uricosuric effect. Hydrochlorothiazide has been shown to cause modest increases in uric acid; the combination of losartan and hydrochlorothiazide tends to attenuate the diuretic-induced hyperuricemia.
The antihypertensive effect of Cozaar Comp is sustained for a 24-hour period. In clinical studies of at least one year's duration, the antihypertensive effect was maintained with continued therapy. Despite the significant decrease in blood pressure, administration of Cozaar Comp had no clinically significant effect on heart rate. In clinical trials, after 12 weeks of therapy with losartan 50 mg /hydrochlorothiazide 12.5 mg, trough sitting diastolic blood pressure was reduced by an average of up to 13.2 mmHg.
Cozaar Comp is effective in reducing blood pressure in males and females, blacks and non-blacks and in younger (<65 years) and older (
Losartan
Losartan is a synthetically produced oral angiotensin-II receptor (type AT1) antagonist. Angiotensin II, a potent vasoconstrictor, is the primary active hormon of the renin-angiotensin system and an important determinant of the pathophysiology of hypertension. Angiotensin II binds to the AT1 receptor found in many tissues (e.g. vascular smooth muscle, adrenal gland, kidneys and the heart) and elicits several important biological actions, including vasoconstriction and the release of aldosterone. Angiotensin II also stimulates smooth-muscle cell proliferation.
Losartan selectively blocks the AT1 receptor. In vitro and in vivo losartan and its pharmacologically active carboxylic acid metabolite E-3174 block all physiologically relevant actions of angiotensin II, regardless of the source or route of its synthesis.
Losartan does not have an agonist effect nor does it block other hormone receptors or ion channels important in cardiovascular regulation. Furthermore, losartan does not inhibit ACE (kininase II), the enzyme that degrades bradykinin. Consequently, there is thus no increase in bradykinin-mediated undesirable effects.
During the administration of losartan the removal of the angiotensin II negative feedback on renin secretion leads to increased plasma-renin activity (PRA). Increase in the PRA leads to an increase in angiotensin II in plasma. Despite these increases, antihypertensive activity and suppression of the plasma aldosterone concentration are maintained, indicating effective angiotensin II receptor blockade. After the discontinuation of losartan,PRA and angiotensin II values fell within 3 days to the baseline values.
Both losartan and its principal active metabolite have a far greater affinity for the AT1 receptor than for the AT2 receptor. The active metabolite is 10- to 40-times more active than losartan on a weight for weight basis.
In a study specifically designed to assess the incidence of cough in patients treated with losartan as compared to patients treated with ACE inhibitors, the incidence of cough reported by patients
