Blosar

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Blosar

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Blosar

Property Description
Active Ingredient Losartan Potassium
Form Oral Tablet (Film-Coated)
Pharmacological Class Angiotensin II Receptor Blocker (ARB)
General Purpose Systemic Blood Pressure Lowering
Origin Synthetic, Non-Peptide Molecule

What Type of Drug is Blosar (Losartan)?

Blosar is a prescription-only (Rx) medication whose active ingredient is Losartan, supplied as the Losartan Potassium salt. It is classified as an Angiotensin II Receptor Blocker (ARB), officially identifying it as an Antihypertensive Agent. Losartan, as a non-peptide molecule, was one of the first compounds of its kind developed to specifically target the body’s renin-angiotensin system (RAS). This approach is clinically recognized for efficacy in patients requiring consistent, long-term blood pressure control.

Blosar's Composition and Physical Form

The composition of Blosar is defined by its sole active ingredient, which is Losartan Potassium, establishing it as a single-ingredient product rather than a combination formula. It is presented in a stable, film-coated tablet intended exclusively for oral administration. The use of the potassium salt form in the manufacturing process is a compositional feature that enhances the molecule's stability and consistent delivery, distinguishing the Losartan formulation from related products that may combine an ARB with a diuretic.

What is the General Purpose of Losartan?

The general therapeutic purpose of Losartan is the sustained, systemic blood pressure lowering required for the long-term management of chronic Hypertension. By acting on the circulatory system, the drug reduces vascular resistance, which in turn eases the excessive strain on the heart and blood vessels. This action represents the core benefit of the drug, supporting the body's cardiovascular system by reducing its overall workload.

Regulatory References

  1. Losartan - StatPearls - NCBI Bookshelf

What side effects are possible with Blosar?

Side Effects and Safety Profile

Blosar (Losartan) is generally well-tolerated, but like all medications, it can cause side effects. These reactions are typically categorized by the system-organ class they affect and their frequency in clinical studies, though individual experience may vary.

Common Adverse Reactions

The most frequently reported side effects (occurring in 1% to 10% of patients) include:

  • Nervous System: Dizziness, headache, vertigo.
  • Respiratory/Infection: Upper respiratory infection, nasal congestion, cough.
  • Musculoskeletal: Back pain, leg pain.
  • Other: Fatigue/asthenia (unusual tiredness or weakness).

Serious and Clinically Significant Safety Concerns

Certain reactions, while less common, are considered serious and require immediate medical attention:

  • Angioedema: Rapid swelling of the face, lips, tongue, or throat, which can cause difficulty breathing. This is a rare, life-threatening allergic reaction.
  • Hypotension: Low blood pressure, which may lead to lightheadedness or fainting, particularly in patients who are volume-depleted (e.g., from high-dose diuretics or excessive vomiting/diarrhea).
  • Hyperkalemia: Abnormally high levels of potassium in the blood, which can affect heart rhythm. Monitoring of potassium levels is often required.
  • Renal Function Deterioration: Changes in kidney function, including acute kidney failure, have been reported, particularly in susceptible patients.

Population-Specific Safety Warnings

Pregnancy Warning (Boxed Warning): Blosar must be discontinued as soon as pregnancy is detected. Use during the second and third trimesters can cause injury or death to the developing fetus, resulting in fetal lung hypoplasia, skeletal deformation, and neonatal renal failure. The drug is generally contraindicated during the latter half of pregnancy.

Use in Children and Elderly: Caution is advised in children under six years old. The elderly generally do not require a dosage adjustment, but those with liver or kidney impairment may require a lower starting dose due to increased exposure to the medication.

Overdose and Emergency Response

The regulatory documentation for Blosar (Losartan) defines overdose by detailing expected clinical manifestations and explicitly mandated emergency actions. The information is strictly descriptive and non-advisory.

The most likely presentation of a Losartan overdose is hypotension (abnormally low blood pressure), which may lead to associated symptoms such as dizziness or fainting. Other documented cardiovascular signs include changes in heart rate, specifically tachycardia (abnormally fast heart rate) or, less commonly, bradycardia (abnormally slow heart rate).

Urgent Medical Attention and Emergency Response

Immediate medical help must be sought for any symptomatic overdose. Regulatory labeling mandates calling Emergency Services (911) immediately if the individual exhibits signs of a severe systemic crisis. These severe outcomes include collapse, experiencing a seizure, trouble breathing, or profound unconsciousness (being unable to be awakened). The Poison Control Helpline should also be contacted following a known or suspected overexposure.

The official management approach focuses on instituting supportive treatment aimed at managing symptomatic hypotension. The regulatory profile states that no specific antidote is known for Losartan. Furthermore, Losartan and its active metabolite are officially documented as not being removable by hemodialysis.

Therapeutic Uses of Blosar

What Blosar treats: main uses and benefits

Blosar contains losartan, an active ingredient belonging to the class of medications known as angiotensin II receptor blockers (ARBs). It is primarily used to manage conditions related to the cardiovascular system and to protect renal function in specific patient populations.

Essential Hypertension

The primary application of Blosar is the treatment of essential hypertension (high blood pressure) in adults, as well as in children and adolescents aged 6 to 18 years. By blocking the action of angiotensin II—a substance in the body that causes blood vessels to tighten—the medication helps blood vessels relax and widen. This process results in a decrease in blood pressure levels.

Renal Protection in Type 2 Diabetes

Blosar is utilized as part of a therapeutic approach for patients with type 2 diabetes and proteinuric hypertension. In these cases, the medication is used to help protect the kidneys and slow the progression of renal disease. It is often measured by its ability to reduce the decline of kidney function over time and decrease the presence of protein in the urine (proteinuria).

Reduction in Risk of Stroke

In adult patients who have both hypertension and a condition known as left ventricular hypertrophy (a thickening of the walls of the left chamber of the heart), Blosar is used to reduce the risk of stroke. While it effectively lowers blood pressure, its use in this context is specifically aimed at decreasing the incidence of cardiovascular morbidity and mortality related to stroke events.

Heart Failure

In certain instances, Blosar is used to treat chronic heart failure when treatment with other specific medications, such as ACE inhibitors, is not considered suitable. It may help improve cardiac function and manage symptoms in patients whose heart muscle is not pumping blood as effectively as it should.

Regulatory References

  1. NIH MedlinePlus Drug Information on Losartan

Eligibility and Restrictions for Use

The eligibility for Blosar (Losartan) is defined by strict regulatory criteria, classifying patient populations into groups where use is permitted, restricted, or strictly prohibited. Losartan is generally permitted for use in adults and in children 6 years of age and older for the treatment of hypertension.

Contraindicated Populations

Regulatory documents state Losartan must not be used in the following groups:

  • Patients with severe hepatic impairment.
  • Women in the second and third trimesters of pregnancy.
  • Patients with known hypersensitivity to Losartan or its components.
  • Diabetic patients or those with kidney impairment (GFR < 60 mL/min/1.73 m²) who are taking aliskiren-containing products.

Restricted and Not Recommended Use ️

Losartan is not recommended for use in children under 6 years of age or in pediatric patients with specific low kidney function. Use is also not recommended during the first trimester of pregnancy or for breastfeeding mothers. Caution is mandated for patients with mild-to-moderate hepatic impairment or those who are volume-depleted, often requiring correction of the condition or a lower starting dose.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Losartan Potassium (Blosar) has officially documented interaction patterns that affect its systemic exposure or result in additive physiological effects, as detailed in regulatory documents.

Pharmacokinetic and Metabolic Interactions

Co-administration with certain substances can formally alter the plasma concentrations of Losartan and its active metabolite. Fluconazole, a CYP2C9 inhibitor, increases the systemic exposure (AUC) of Losartan by 70% while decreasing the AUC of the active metabolite by 40%. Conversely, CYP inducers like Phenobarbital can reduce the exposure of both Losartan and its active metabolite. Cimetidine is also documented to cause a modest increase in Losartan's AUC.

Pharmacodynamic and Additive Effects

Losartan’s effects may be amplified when combined with other medicines or supplements:

  • Agents increasing serum potassium: Co-administration with potassium-sparing diuretics or potassium supplements increases the official risk of hyperkalemia (high potassium levels) due to an additive effect.
  • Lithium: Losartan may reduce the renal clearance of lithium, increasing the risk of lithium toxicity.
  • Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Combining with NSAIDs can increase the official risk of worsening renal function and may reduce Losartan’s blood pressure lowering effect. This risk is specifically documented as heightened in the elderly or those with compromised renal function.

Regulatory Restrictions

Co-administration with Aliskiren, another drug that targets the RAS, is formally contraindicated by regulatory agencies in patients with diabetes or moderate-to-severe renal impairment.

Mechanism of Action

How Blosar Works: Targeted Pathway Modulation


Selective AT1 Receptor Blockade

Blosar exerts its effect by acting as a selective antagonist of the Angiotensin II Type 1 (AT1) receptor. The drug and its primary active metabolite, EXP 3174, bind competitively to the AT1 receptor, which is widely present in vascular smooth muscle, adrenal glands, and kidneys. This binding physically prevents the primary effector molecule, Angiotensin II, from activating the receptor. This action immediately suppresses the vasoconstrictive signal and the release of aldosterone that normally follow AT1 activation.


Modulating the RAAS Cascade and Vasculature

This blockade acts within the Renin-Angiotensin-Aldosterone System (RAAS) cascade, a principal neurohumoral pathway involved in maintaining fluid volume and pressure balance. By inhibiting the downstream effects of Angiotensin II, Blosar modifies the overall activity of the RAAS signaling sequence. This modification results in predictable physiological changes: specifically, the relaxation and widening of blood vessels (vasodilation) and a decrease in the retention of sodium and water by the kidneys. These actions adjust the state of systemic vascular resistance and fluid dynamics.

Dosage and Administration Information

How Blosar is Used: Official Administration Guidelines

Losartan (Blosar) is a medication for oral administration only, available as film-coated tablets in 25 mg, 50 mg, and 100 mg strengths, as well as a 10 mg/mL oral suspension. The primary dosing pattern for maintenance is once daily across all approved adult indications. Administration offers intake flexibility, as the medication may be taken with or without food. Tablets should be swallowed whole with water. In the case of the oral suspension, a calibrated measuring device is required for accurate dosing.

Dosing regimens are defined by the specific condition being addressed. For most adults with hypertension or diabetic nephropathy, the standard starting dose is 50 mg once daily, with the dose titrated up to a maximum of 100 mg once daily based on clinical response. For heart failure management, the initial dose is lower at 12.5 mg once daily and may be titrated up to a maximum of 150 mg once daily.

Specific adjustments to the starting dose are required for certain populations. Patients with pre-existing hepatic impairment or those who are volume depleted (e.g., from high-dose diuretic therapy) should initiate therapy at a lower dose of 25 mg once daily. The maximal antihypertensive effect is typically achieved three to six weeks after starting treatment, which informs the timing of any subsequent dose adjustments.

Summary of Key Procedural Instructions

Administration Entity Description
Route of Administration Oral (Tablet or Suspension)
Frequency Once Daily
Timing in Relation to Meals With or without food
Required Adjustments Lower 25 mg start for Hepatic Impairment or Volume Depletion

If a dose is missed, instructions advise taking the dose as soon as it is remembered unless it is nearly time for the next scheduled dose, in which case the missed dose should be skipped; a double dose must never be taken.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Blosar

Evidence for Use in High Blood Pressure (Hypertension)

The evidence for the use of Blosar in high blood pressure is based on randomized controlled trials (RCTs) that compared the medicine both to inactive placebos and to other established blood pressure medications. Researchers primarily monitored changes in Systolic and Diastolic Blood Pressure (BP), as well as the long-term rates of major cardiovascular events. The studies have involved a population of adults with mild to moderate high blood pressure.

In trials, Blosar was associated with measured changes in blood pressure values over the measured 24-hour period, compared to placebo. Long-term outcome research, which involved hypertensive patients who also had Left Ventricular Hypertrophy (LVH), provided data that helped describe patterns in the occurrence of serious cardiovascular events, such as stroke, compared to another medicine studied (atenolol).

However, the analysis of these long-term studies indicates that the pattern observed regarding cardiovascular event rates in patients with LVH may not apply uniformly to all subgroups, with official summaries noting that the observed patterns were not consistently seen in Black patients in that specific trial.


Evidence for Use in Diabetic Kidney Disease (Nephropathy in Type 2 Diabetes)

The research examining Blosar for kidney disease in Type 2 Diabetes is primarily derived from multinational, placebo-controlled trials specifically designed to monitor renal outcomes over several years. These studies monitored a specific composite endpoint that included markers of kidney failure, such as the doubling of serum creatinine, progression to the need for dialysis or transplant, and all-cause death. The studies focused on patients with Type 2 Diabetes who already had hypertension and overt proteinuria.

Research highlights changes measured during the study period, with trials reporting an observed pattern regarding the measured frequency of the composite renal endpoint compared to the placebo group. Studies also described patterns of change in measured proteinuria levels in the observed populations.


Long-Term Data and Follow-Up Duration

The research exploring changes related to the circulatory system in hypertension and changes related to kidney function in diabetic kidney disease is dependent on the results observed during longer-duration follow-up periods, often extending for approximately three to five years. For the pediatric population, the long-term effects on growth, development, and eventual cardiovascular outcomes are not yet established.


What Remains Uncertain in the Research Landscape

The evidence highlights what is known, but also what is still uncertain: specific findings related to cardiovascular event rates in hypertensive patients with LVH were not consistently observed across all racial groups studied in the major outcome trials, and data for the durability of all observed outcomes beyond five years are still emerging.

Key Studies & References

  1. Losartan: MedlinePlus Drug Information (Authoritative patient-focused summary used for general context and pediatric age ranges)

Frequently Asked Questions (FAQ)

Common questions about Blosar (FAQ)

Q: Are there any major diet restrictions mentioned for people taking Blosar?

Official drug documents describe a need for caution regarding the intake of potassium supplements or potassium-containing salt substitutes. This is because Losartan, the active ingredient in Blosar, can elevate potassium levels, increasing the potential for hyperkalemia (high potassium). Some sources mention that grapefruit juice may result in altered exposure to the medicine.

Q: Is Blosar safe for people who have kidney issues?

The official labeling indicates that monitoring of patients with existing compromised renal (kidney) function is often necessary. Regulatory documents indicate there is an increased potential for kidney function worsening, particularly when Blosar is used alongside certain non-prescription pain relievers like NSAIDs. Furthermore, Blosar is strictly contraindicated (must not be used) in diabetic patients with kidney impairment who are also taking a medicine called Aliskiren.

Q: What should I know about taking Blosar if I have heart problems?

Blosar is indicated for the treatment of high blood pressure (hypertension) and to lower the risk of stroke in patients who also have a heart condition called Left Ventricular Hypertrophy (LVH). Low blood pressure (hypotension) is listed as a serious safety concern in official documents. Consultation with a healthcare provider is important for determining appropriate use based on individual health status.

Q: What does the term 'Black Box Warning' mean for Blosar?

In regulatory documents, the most serious warnings are presented in a Boxed Warning (sometimes called a 'Black Box Warning'). For Blosar, this warning highlights the serious risk of fetal toxicity, meaning the drug can cause injury or death to a developing fetus if used during the last six months of pregnancy. Regulatory documents state that Blosar must be discontinued as soon as a pregnancy is detected.

Q: Is a follow-up blood test required when starting Blosar?

Official product information indicates that follow-up tests are often required. Monitoring of serum potassium levels and kidney function are generally needed when starting treatment with Blosar. This monitoring is used to observe serum potassium levels and how the medicine is affecting kidney function.

Q: What is the difference between the active and inactive ingredients in Blosar?

The active ingredient in Blosar is Losartan Potassium, which is the substance responsible for the therapeutic effect. All other components, such as lactose, cellulose, and colorings, are referred to as inactive ingredients (excipients). These ingredients are included to stabilize the tablet, aid in manufacturing, and help with consistent delivery.

Q: Can Blosar be split or crushed, based on regulatory information?

Official administration guidelines state that the tablets should be swallowed whole with water. Some formulations of the tablets may be scored (marked) to allow for division into equal doses if needed for precise dosing. Any alteration to the tablets should be discussed with a healthcare provider.

Q: What is the purpose of the 'titration' or slow increase in Blosar dose?

Dose titration refers to the process where the dosage is gradually adjusted over time. Official dosage instructions indicate that this is done at weekly intervals and is adjusted based on the patient's tolerance and their blood pressure response. This slow approach allows for the adjustment of the dose based on the patient's response.

Q: Is Blosar considered a first-line treatment for its approved condition?

Regulatory information indicates that Angiotensin II receptor antagonists, which include Blosar, are described as one of several preferred agents for the initial management of high blood pressure, according to current guidelines. The determination of whether Blosar is an appropriate initial therapy is a decision made by a healthcare provider.

Q: Are there official warnings about combining Blosar with alcohol?

Official drug interaction information mentions that Losartan and alcohol (ethanol) can have additive effects in lowering blood pressure. This combined effect could potentially lead to side effects such as dizziness, lightheadedness, or fainting. Patients are generally advised to discuss the use of alcohol with their healthcare provider.

Q: Are there any specific activities to avoid while taking Blosar?

Official warnings note that Blosar can cause dizziness, lightheadedness, or fainting, especially when getting up quickly from a sitting or lying down position. It is advised to use caution to avoid these postural changes too rapidly, as this can help reduce the potential risk of falling. Official guidance on activities is provided by the prescribing physician.

Q: Do you need to avoid certain types of drinks (like caffeine or juice) while on Blosar?

While there are generally no major blanket restrictions on common drinks, some authoritative sources have specifically mentioned that grapefruit or grapefruit juice may result in altered exposure to the medicine for some individuals. Any potential concerns about drinks should be directed to a healthcare provider.

Q: How quickly does Blosar leave the system after the last dose?

Pharmacokinetic data from regulatory documents show that the active compound, Losartan, has a half-life (the time it takes for half of the dose to be eliminated) of approximately 1.5 to 2.5 hours. Its main active metabolite, which continues to work in the body, has a longer half-life of approximately 6 to 9 hours.

Q: Does Blosar affect fertility in men or women?

Nonclinical toxicology studies in male rats given high doses of Losartan showed no effect on their fertility or reproductive performance. Studies in female rats did show some effects, but only at toxic doses, and the direct relationship between these nonclinical findings and human treatment is uncertain.

Q: Are there any reports of Blosar affecting vision?

Although not listed as a common side effect, some serious adverse effect data has included reports of symptoms such as blurred vision. Any changes to vision while taking the medication should be promptly reported to a healthcare professional.

Q: Do official sources describe Blosar as a 'cure' for the condition it treats?

No, official sources describe Blosar as a medication indicated for the management (treatment) of chronic conditions like high blood pressure. The drug works to control the condition and reduce risk factors, but it is not described as a cure for hypertension or diabetic kidney disease.

Q: Is it common for Blosar to be taken with another prescription drug for the same condition?

Official documents state that Losartan may be administered with other antihypertensive agents, such as diuretics, beta-blockers, or calcium channel blockers. This approach, known as combination therapy, is sometimes used for the management of high blood pressure.

Q: Does Blosar have any known effect on blood sugar levels?

Blosar is officially indicated for the treatment of kidney disease in people with Type 2 diabetes. Regulatory documents also contain warnings that the dose of antidiabetic drugs may require adjustment when co-administered with Blosar. Dosage adjustment decisions are made by a healthcare provider.

Q: Are there specific times of day Blosar is recommended to be taken?

Official instructions specify that the drug is taken once daily. While it can be taken with or without food, some regulatory guidance notes that the maximum dose (100 mg) can be taken once daily in the morning. The exact timing recommendation is typically provided by the prescribing physician.

Q: Is it common for people to feel nauseous when they first start Blosar?

While individual experiences vary, official lists of common side effects (those occurring in 1% to 10% of patients) do not include nausea. However, a related digestive side effect, such as diarrhea, has been reported in authoritative sources.

How should Blosar be stored and disposed of?

How to Store and Dispose of Blosar?

The storage and handling of Blosar (losartan potassium) tablets are defined by official regulatory requirements to ensure product stability and safety.

Required Storage Conditions

The medication must be stored at room temperature, typically 20 C to 25 C (68 F to 77 F), with permitted excursions up to 30 C. It is mandatory to keep the product from freezing and away from excessive heat.

Losartan tablets must be stored in the original container with the container tightly closed to protect from light and moisture.

Child Safety and Disposal

It is an official requirement to keep the product out of the reach and sight of children.

Disposal must be handled according to pharmaceutical waste guidelines; do not dispose of Blosar via wastewater or household trash. Unused or expired medication should be disposed of through a medicine take-back program or as directed by a healthcare professional.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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