Osartil50 mg

Osartil 50 mg is an angiotensin II receptor blocker (ARB) widely prescribed for the management of high blood pressure and the protection of kidney function in patients with type 2 diabetes. It is one of the most commonly used antihypertensive generics in Bangladesh, available under numerous brand names.

1. Treatment of Hypertension

Osartil 50 mg tablet is indicated for the treatment of hypertension (high blood pressure) in adults. It can be used as a single agent (monotherapy) or combined with other antihypertensive medicines, such as thiazide diuretics, when blood pressure is not adequately controlled by Losartan alone. By relaxing blood vessels, Losartan helps lower systolic and diastolic blood pressure, reducing the long-term risk of stroke, heart attack, and other cardiovascular complications associated with uncontrolled hypertension.

2. Renal Protection in Type 2 Diabetic Patients with Proteinuria

Osartil 50 mg tablet is indicated to delay the progression of kidney (renal) disease in hypertensive patients with type 2 diabetes who have proteinuria, defined as a urinary albumin-to-creatinine ratio greater than 300 mg/g. In these patients, Losartan slows the decline in kidney function, reduces the amount of protein lost in urine, and lowers the risk of progression to end-stage renal disease requiring dialysis.

3. Cardiovascular Risk Reduction

In hypertensive patients with documented left ventricular hypertrophy (enlargement of the heart's main pumping chamber), Losartan has been shown in clinical studies to reduce the risk of stroke compared to some other antihypertensive agents, making it a preferred option for patients with this specific risk profile.

Always take Osartil 50 mg under the guidance of a registered physician. Self-medication for blood pressure or kidney conditions can be dangerous.

Angiotensin-ll receptor blocker

Mechanism of Action

Osartil 50 mg was the first non-peptide, orally active angiotensin II receptor blocker (ARB) developed for clinical use. It works by selectively binding to and blocking the angiotensin II type-1 (AT1) receptor, which is found in many tissues throughout the body, including vascular smooth muscle, the adrenal gland, the kidneys, and the heart.

Under normal physiological conditions, angiotensin II is a powerful chemical messenger that causes blood vessels to constrict (narrow) and stimulates the adrenal gland to release aldosterone, a hormone that promotes salt and water retention. Both of these actions raise blood pressure. By blocking the AT1 receptor, Osartil 50 mg prevents angiotensin II from exerting these effects, resulting in:

• Relaxation and widening (vasodilation) of blood vessels
• Reduced secretion of aldosterone
• Lower blood pressure
• Reduced workload on the heart

Unlike ACE inhibitors, Losartan does not affect the breakdown of bradykinin, which is why it is associated with a lower incidence of dry cough, a common side effect of ACE inhibitor therapy.

Pharmacokinetics

Losartan is well absorbed after oral administration and undergoes substantial first-pass metabolism in the liver, primarily via the cytochrome P450 enzymes CYP2C9 and CYP3A4. A significant portion of Losartan is converted into an active carboxylic acid metabolite known as EXP3174 (E-3174), which is more potent than the parent drug and is largely responsible for the sustained blood-pressure-lowering effect.

• Oral bioavailability: Approximately 33%
• Peak plasma concentration: Around 1 hour for Losartan; 3 to 4 hours for its active metabolite
• Plasma protein binding: Greater than 99% for both Losartan and its metabolite
• Elimination half-life: About 2 hours for Losartan; 6 to 9 hours for the active metabolite
• Excretion: Approximately 35% renal and 60% biliary/faecal elimination

The longer half-life of the active metabolite allows Osartil 50 mg to provide effective 24-hour blood pressure control with once-daily dosing in most patients.

Osartil 50 mg can interact with several other medicines, supplements, and substances. Patients should inform their doctor or pharmacist about all medications, herbal products, and supplements they are taking before starting Osartil 50 mg.

Medicines That Reduce Losartan's Effectiveness

• Rifampicin: Reduces the level of Losartan's active metabolite, which may lower its blood-pressure-lowering effect.
• Fluconazole: Also reduces the level of Losartan's active metabolite through inhibition of its metabolic conversion.
• Indomethacin and other NSAIDs: Non-steroidal anti-inflammatory drugs may attenuate (reduce) the antihypertensive effect of Losartan.

Medicines That Increase the Risk of High Potassium (Hyperkalemia)

• Potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride)
• Potassium supplements
• Salt substitutes containing potassium

Combining any of the above with Osartil 50 mg may lead to clinically significant increases in serum potassium levels and should only be done under close medical supervision with periodic blood monitoring.

Medicines That Increase Blood-Pressure-Lowering Effect

Concomitant use of Osartil 50 mg with hydrochlorothiazide or other diuretics can potentiate (enhance) the antihypertensive effect, which is often used intentionally for patients with difficult-to-control blood pressure, but may also increase the risk of low blood pressure (hypotension) and should be monitored.

Medicines That Increase the Risk of Kidney Impairment

Using an ACE inhibitor, an angiotensin receptor blocker (such as Losartan), an NSAID, and a thiazide diuretic together at the same time substantially increases the risk of renal (kidney) impairment, particularly in patients who are elderly, dehydrated, or have pre-existing kidney disease.

Other Notable Interactions

• Lithium: ARBs may increase serum lithium concentrations and the risk of lithium toxicity; concurrent use requires careful monitoring of lithium levels.
• Aliskiren: Dual blockade of the renin-angiotensin system with Aliskiren is not recommended, especially in patients with diabetes or renal impairment (see Contraindications).
• Other antihypertensive agents: May have additive blood-pressure-lowering effects when combined with Losartan.

The side effects associated with Osartil 50 mg are generally mild and transient in nature. Most patients tolerate the medicine well, but as with any medication, side effects can occur.

Common Side Effects

• Dizziness
• Diarrhea
• Nasal congestion
• Cough
• Upper respiratory tract infection

Other Reported Side Effects

• Fatigue
• Oedema (fluid retention/swelling)
• Abdominal pain
• Chest pain
• Nausea
• Headache
• Pharyngitis (sore throat)

When to Seek Medical Attention

Patients should contact their doctor immediately if they experience any of the following less common but more serious effects:

• Signs of an allergic reaction, such as swelling of the face, lips, tongue, or throat, or difficulty breathing (angioedema)
• Signs of high potassium levels, such as muscle weakness, irregular heartbeat, or tingling sensations
• Severe dizziness, fainting, or symptoms of very low blood pressure
• Yellowing of the skin or eyes, or signs of liver problems
• A significant decrease in urine output

This is not a complete list of side effects. Patients experiencing any unusual or persistent symptoms while taking Osartil 50 mg should consult their physician.

Category D for pregnancies. If Osartil 50 mg is given during the second or third trimester of pregnancy, the risk to the fetus increases. Given that numerous medicines are excreted in human milk and that it is unknown whether Osartil 50 mg is one of them, a choice should be taken regarding whether to stop breastfeeding or stop taking the medication, taking into account the significance of the medication to the mother.

• Pregnancy risk: Use of Osartil 50 mg during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Treatment should be discontinued as soon as pregnancy is detected.
• Symptomatic hypotension: In patients who are intravascularly volume-depleted (for example, those on high-dose diuretic therapy), symptomatic low blood pressure may occur after starting Osartil 50 mg. Correcting volume depletion before initiating treatment is recommended.
• Hepatic impairment: Plasma concentration of Osartil 50 mg is significantly increased in patients with cirrhosis. A lower starting dose should be considered, and these patients should be monitored closely.
• Renal function changes: Changes in kidney function, including renal failure, have been reported in patients with impaired kidney function. Periodic monitoring of renal function is advised, particularly in at-risk patients.
• Renal artery stenosis: As with other drugs that affect the renin-angiotensin-aldosterone system, patients with bilateral renal artery stenosis, or stenosis of the artery to a single functioning kidney, may experience increases in blood urea and serum creatinine. These changes are usually reversible upon stopping treatment.
• Hyperkalemia: Osartil 50 mg should not be used together with potassium-sparing diuretics, as this combination can lead to elevated potassium levels in the blood.
• Dual RAAS blockade: Combining Osartil 50 mg with other medicines that block the renin-angiotensin-aldosterone system (such as ACE inhibitors or Aliskiren) is generally not recommended due to an increased risk of hypotension, hyperkalemia, and kidney impairment.

Limited data is available regarding overdosage of Osartil 50 mg in humans. The most likely manifestations of overdose are expected to be related to its blood-pressure-lowering action.

Signs and Symptoms

• Hypotension (low blood pressure)
• Tachycardia (rapid heartbeat); bradycardia (slow heartbeat) may occur from excessive vagal (parasympathetic) stimulation

Management of Overdose

There is no specific antidote for Osartil 50 mg overdose. Treatment is supportive and symptomatic, and may include:

• Inducing emesis or gastric lavage if the overdose is recent
• Administration of activated charcoal to reduce drug absorption
• Close monitoring of vital signs, including blood pressure and heart rate
• Supportive treatment such as intravenous fluids to manage hypotension

Losartan and its active metabolite are not significantly removed by haemodialysis. In case of a suspected overdose, immediate medical attention should be sought.

• Store in a cool, dry place, away from direct light and heat, ideally below 30°C.
• Keep the medicine in its original packaging until ready for use to protect it from moisture.
• Keep out of the reach and sight of children.
• Do not use the medicine after the expiry date printed on the package.

Renal Impairment

Dose adjustment of Osartil 50 mg may be required based on the degree of kidney function impairment, as summarised below:

Patients with Intravascular Volume Depletion

For the small proportion of patients who are intravascularly volume-depleted — for example, those treated with high-dose diuretics — a starting dose of 25 mg once daily is recommended. Volume status should be corrected where possible before starting treatment.

Hepatic Impairment

Pharmacokinetic data show that plasma concentrations of Losartan are significantly increased in patients with cirrhosis of the liver. A lower starting dose should be considered for patients with a history of hepatic impairment, and these patients should be monitored closely for signs of excessive blood-pressure lowering. Osartil 50 mg may be administered with or without food, and may be given alongside other antihypertensive agents as needed.

Elderly Patients

No initial dosage adjustment is necessary for patients up to 75 years of age. For patients over 75 years, clinical experience is limited, and a lower starting dose of 25 mg once daily is recommended.

Pediatric Use

Safety and effectiveness data on the use of Osartil 50 mg in children are more limited than in adults. Use in pediatric patients should only be initiated and supervised by a specialist physician experienced in treating childhood hypertension.

Angiotensin-ll receptor blocker

The first angiotensin II receptor blocker that is orally active without a peptide is Osartil 50 mg. It binds to the AT1 receptor, which is present in numerous tissues (such as the heart, kidneys, adrenal glands, and vascular smooth muscle), and inhibits several critical biological processes, such as vasoconstriction and the production of the hormone aldosterone that causes hypertension.

Category D for pregnancies. If Osartil 50 mg is given during the second or third trimester of pregnancy, the risk to the fetus increases. Given that numerous medicines are excreted in human milk and that it is unknown whether Osartil 50 mg is one of them, a choice should be taken regarding whether to stop breastfeeding or stop taking the medication, taking into account the significance of the medication to the mother.