Overview

Losartan is an angiotensin receptor blocker (also called an angiotensin-II receptor antagonist (AIIRA)). It is used to lower hypertension (high blood pressure). People with high blood pressure often do not feel unwell but, left untreated, high blood pressure can harm the heart and damage blood vessels. Losartan is also used to treat heart failure, which is a condition where your heart is not working as well as it should.
Losartan works by blocking the effect of a chemical called angiotensin II which is made in your bloodstream. Angiotensin II causes your blood vessels to narrow and also leads to the production of another chemical called aldosterone, which increases the amount of fluid in your blood. By preventing the action of angiotensin II, losartan reduces how much work your heart has to do and lowers your blood pressure. It also has a protective effect on your kidneys.

KELOSTIF is used for?

Treating high blood pressure alone or with other medicines. It is used in certain patients to decrease the risk of stroke. It is used in certain patients to treat kidney problems caused by diabetes (diabetic nephropathy). It may also be used for other conditions as determined by your doctor. Losartan is an angiotensin II receptor blocker (ARB). It works by relaxing blood vessels. This helps to lower blood pressure.

Warnings

you are allergic to any ingredient in losartan

you are pregnant

the patient is a child with severe kidney problems

you are taking a medicine that contains aliskiren and you also have diabetes or kidney problems. Check with your doctor or pharmacist if you are not sure if a medicine you take contains aliskiren

Contact your doctor or health care provider right away if any of these apply to you.

Contraindications

Known hypersensitivity to losartan or any ingredient in the formulation.

Side Effects

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Back pain,diarrhea,dizziness,symptoms of upper respiratory tract infection (eg, cough, runny or stuffy nose, sneezing, sore throat),tiredness.

Dosage

Oral:
Disclaimer:To be taken only after consulting with the doctor.

Storage

Store losartan at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. If your pharmacist prepares a suspension of losartan, store as directed by your pharmacist. Keep losartan out of the reach of children and away from pets.

Pharmacology

Mechanism of Action

Angiotensin II [formed from angiotensin I in a reaction catalyzed by angiotensin converting enzyme (ACE, kininase II)], is a potent vasoconstrictor, the primary vasoactive hormone of the renin-angiotensin system and an important component in the pathophysiology of hypertension. It also stimulates aldosterone secretion by the adrenal cortex. Losartan and its principal active metabolite block the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor found in many tissues, (e.g., vascular smooth muscle, adrenal gland). There is also an AT2 receptor found in many tissues but it is not known to be associated with cardiovascular homeostasis. Both Losartan and its principal active metabolite do not exhibit any partial agonist activity at the AT1 receptor and have much greater affinity (about 1000-fold) for the AT1 receptor than for the AT2 receptor. In vitro binding studies indicate that Losartan is a reversible, competitive inhibitor of the AT1 receptor. The active metabolite is 10 to 40 times more potent by weight than Losartan and appears to be a reversible, non-competitive inhibitor of the AT1 receptor.

Neither Losartan nor its active metabolite inhibits ACE (kininase II, the enzyme that converts angiotensin I to angiotensin II and degrades bradykinin); nor do they bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation.

Interactions

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%.