Kardiostan

Kardiostan

losartan

Manufacturer:

Interphil

Distributor:

Interphil
Full Prescribing Info
Contents
Losartan potassium.
Description
Losartan is an angiotensin II receptor antagonist which is administered orally as potassium salt. It is a potent antihypertensive drug which may be given alone or in combination with diuretics.
Action
Pharmacology: Losartan is a nonpeptide, highly selective angiotensin II subtype I (AT1) receptor antagonist which relaxes the blood vessels and lowers blood pressure by competing with angiotensin II from binding at the AT1 receptor. Its active metabolite identified as E3174, binds noncompetitively and irreversibly to AT1 receptors.
Pharmacokinetics: Losartan is well-absorbed orally from the gastrointestinal tract and has a bioavailability of approximately 33% as a result of the extensive first-pass metabolism. Upon oral administration, 14% of the drug is metabolized in the liver via oxidation by CYP2C9 and CYP3A4 to a more potent active metabolite, E3174. This metabolite is pharmacologically more active than the parent compound, having 20-30 times greater the affinity for AT1 receptors.
The mean peak concentration (Cmax) of losartan is reached 1 hr after administration and 3-4 hrs for its active metabolite. Both losartan and E3174 are >98% protein bound.
The terminal t½ of the parent drug is about 1.5-2.5 hrs and 3-9 hrs for E3174. Losartan is eliminated via renal (35%) and hepatic (60%) routes as unchanged drug and metabolites.
Indications/Uses
Used in the management of hypertension especially in patients who, upon administration of ACE inhibitors, develop cough as an adverse event.
Losartan reduces the risk of cardiovascular morbidity and mortality, including stroke and myocardial infarction in patients with left ventricular hypertrophy and offers renal protection in patients with diabetic nephropathy.
The 7th Report on the Joint National Commission (JNC 7) on prevention, detection, evaluation and treatment of high blood pressure in the United States prefers thiazide diuretics as initial therapy for hypertension, but when a diuretic cannot be used or a compelling indication is present (ie, cough developed from the use of ACE inhibitors), losartan may be given as initial therapy.
Dosage/Direction for Use
Hypertension: Usual Dose: 50 mg. This may be increased to 100 mg/day given as 1 or 2 doses, when necessary. The dose may be adjusted based on blood pressure measures of the patient.
Patients with Diabetic Nephropathy: Initial Dose: 50 mg/day and may be increased to 100 mg depending on the patient's response to Kardiostan.
Hepatic Impairment: Administration of losartan in patients with cirrhosis showed a significant increase of levels of losartan and its active metabolite in the blood. Initial dose for patients with hepatic impairment or history of such is 25 mg.
In the absence of hepatic insufficiency among elderly, losartan may be given 50 mg daily. Dose may be increased to 100 mg/day given in 2 doses, when necessary.
Renal Impairment: In cases of moderate to severe renal impairment, intravascular or salt depletion eg, those in patients undergoing hemodialysis or under treatment with diuretics, the initial dose may be reduced to 25 mg/day.
In a recent study, the use of losartan 0.75 mg/kg (maximum of 50 mg) in hypertensive children 6-16 years proved to be beneficial in reducing diastolic blood pressure within 3 weeks. Losartan is generally well tolerated when given up to a dosage of 1.44 mg/kg/day (maximum of 100 mg).
Administration: Administration of losartan with food does not significantly affect the absorption of Kardiostan. Thus, it may be given with or without food.
Overdosage
Overdosage of losartan may lead to hypotension or tachycardia. If this occurs, patient must be treated accordingly. Losartan and its metabolites are not removed via hemodialysis.
Contraindications
Pregnancy and hypersensitivity to losartan and any component of Kardiostan.
Use in pregnancy: Use of losartan during the 2nd and 3rd trimester of pregnancy may cause low blood pressure or severe kidney failure and is harmful, if not fatal to the fetus or infant. A case of oligohydramnios (decreased amniotic fluid), fetal effects and subsequent fetal death were reported in a patient exposed to losartan during 20-31 weeks of pregnancy. Treatment with losartan should be discontinued with the 1st sign of pregnancy.
Special Precautions
Monitoring of Blood Chemistry: Orthostatic hypotension may develop with the use of losartan in patients with volume depletion. Volume depletion should then be corrected before the start of treatment with losartan. A low initial dose of Kardiostan is therefore recommended.
The level of serum potassium and creatinine must be monitored at least once or twice a year. If blood pressure of the patient has already been stabilized, follow-up visits can be done at 3-6 months interval.
Patients with Renal Impairment: Lowering of the dose is necessary for patients with impaired renal function who exhibit electrolyte imbalance and are intravascularly volume depleted. Risk of hyperkalemia accompanies treatment with losartan. Thus, serum potassium concentrations should be monitored especially in elderly patients with renal impairment (see Dosage & Administration).
Losartan should be used with caution in patients diagnosed to have renal artery stenosis.
Patients with Hepatic Impairment: Low dose of losartan should be given to patients with hepatic disease as this may delay the excretion of Kardiostan from the body (see Dosage & Administration).
Use in lactation: The excretion of losartan in breast milk has not yet been established. In a study done in animals, losartan was found to pass into the milk of lactating rats. Thus, caution should be taken when administering Kardiostan to lactating mothers.
Use in children: The use of losartan in children <6 years with creatinine clearance <30 mL/min/1.73 m2 has not yet been established.
Use in the elderly: Adjustment of losartan doses is not necessary except for elderly patients with hepatic insufficiency.
Elderly patients with renal malfunctions should be monitored for serum potassium levels as treatment with losartan may cause hyperkalemia (see Dosage & Administration).
Use In Pregnancy & Lactation
Use in pregnancy: Use of losartan during the 2nd and 3rd trimester of pregnancy may cause low blood pressure or severe kidney failure and is harmful, if not fatal to the fetus or infant. A case of oligohydramnios (decreased amniotic fluid), fetal effects and subsequent fetal death were reported in a patient exposed to losartan during 20-31 weeks of pregnancy. Treatment with losartan should be discontinued with the 1st sign of pregnancy.
Use in lactation: The excretion of losartan in breast milk has not yet been established. In a study done in animals, losartan was found to pass into the milk of lactating rats. Thus, caution should be taken when administering Kardiostan to lactating mothers.
Adverse Reactions
Treatment with angiotensin II receptor antagonists is associated with dizziness and headache. Hypotension, characterized as orthostatic and dose-related, was seen in patients with volume depletion eg, those receiving high-dose diuretics.
Other adverse effects associated with the use of losartan include gastrointestinal disturbance, fatigue, muscle and joint pains, congestion, hyperkalemia, back pain, vertigo, migraine, acute pancreatitis and increase in liver enzymes. Losartan causes cough to a lesser degree than that of ACE inhibitors.
Hypersensitivity reactions eg, rash, urticaria, pruritus and angioedema have been reported with the use of losartan. There were also reports of immune thrombocytopenia, hepatotoxicity, rhabdomyolysis, anaphylactic reactions and vasculitis including Henoch-Schonlein purpura.
Atypical cutaneous lymphoid infiltrates, psoriasis, exacerbation and taste disturbance were reported in patients taking losartan but disappeared after cessation of Kardiostan.
Symptomatic anemia and decreased hemoglobin concentrations have been reported in patients with renal impairment.
There is no significant difference found between the adverse effects for children as compared to those reported in adults.
Drug Interactions
Concomitant use of losartan with fenofibrate is beneficial in the treatment of patients with gout and hypertriglyceridemia.
Losartan shows no effect on the pharmacokinetics of warfarin and digoxin.
Administration of losartan with fluconazole, phenytoin and grapefruit juice inhibits the metabolism of losartan to its active metabolite. Although not yet established, the possibility of decreased therapeutic effect of losartan may be considered.
Rifampicin was found to induce the metabolism of losartan to its active metabolite, E3174 thereby, reducing levels of both losartan and E3174 in the circulation.
Losartan does not affect the pharmacokinetic properties of phenytoin and orlistat.
Administration of losartan with spironolactone and other potassium-sparing diuretics may lead to the occurrence of hyperkalemia. Physicians are advised to monitor patient's serum potassium level.
The use of losartan with ACE inhibitors and β-blockers potentiates the antihypertensive effects of losartan.
There have been reports of lithium intoxication when losartan was given to patients treated with lithium.
Storage
Store at a temperature not exceeding 25°C.
ATC Classification
C09CA01 - losartan ; Belongs to the class of angiotensin II receptor blockers (ARBs). Used in the treatment of cardiovascular disease.
Presentation/Packing
FC tab 50 mg x 100's. 100 mg x 100's.
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