Losa

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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 Losa

Property Description
Active Ingredient Losartan potassium
Form Film-coated tablets
Pharmacological Class Angiotensin Receptor Blocker (ARB)
General Purpose Managing elevated blood pressure
Origin Synthetic, Non-peptide molecule

What Type of Medicine is Losa?

Losa is a common trade name for the pharmaceutical compound Losartan potassium, which is classified as an Angiotensin Receptor Blocker (ARB), a primary category of medication clinically recognized for managing elevated blood pressure. Losartan is a synthetic, non-peptide molecule taken orally that works as an antihypertensive agent. As a prescription-only drug, Losa is specifically positioned for adult patients requiring sustained daily management of hypertension, offering a distinct class of action compared to older agents.

Losartan Composition and Available Form

The core component of Losa is the active ingredient, Losartan potassium, which is the precise salt formulation necessary for achieving the therapeutic effect. The drug is consistently provided as a single-ingredient product, and its most common preparation is in the form of film-coated tablets for oral ingestion, ensuring stability and accurate delivery. Losartan and its active metabolite act as a selective antagonist at the AT1 receptor, leading to reduced peripheral resistance. Its composition includes Losartan potassium along with a tablet base composed of inert excipients and fillers necessary to create the solid dosage form.

The General Purpose of Angiotensin Receptor Blockers

The overarching general purpose of ARBs, such as Losartan, is to facilitate the lowering of elevated blood pressure by targeting a specific hormonal pathway that controls the constriction of blood vessels. Losartan works by blocking the effects of the powerful natural signal, Angiotensin II, at the AT1 receptor, which prevents the signal from tightening vessel walls. By inhibiting this action, the medication allows blood vessels to relax and widen, reducing the total resistance to blood flow. This mechanism is primarily utilized to maintain blood pressure within a controlled, healthy range, reducing strain on the cardiovascular system and supporting long-term cardiovascular health.

Regulatory References

  1. MedlinePlus
  2. https://www.ncbi.nlm.nih.gov/books/NBK539017/

What side effects are possible with Losa?

Possible Side Effects and Safety Information

The safety profile of Losa (Losartan potassium) is documented through clinical trial data and post-marketing surveillance, with adverse reactions classified according to official frequency standards. This information is derived from government regulatory labeling, reflecting the official regulatory perspective on the drug’s potential effects.


Frequency-Classified Adverse Reactions

Adverse reactions are organized by the probability of occurrence, as defined in official regulatory texts.

Classification Examples of Documented Effects
Common Dizziness, upper respiratory infection, nasal congestion, back pain, headache.
Uncommon Palpitations, chest pain, sleep disorders, vertigo, abdominal pain, nausea, diarrhea, rash, edema, asthenia/fatigue.
Rare Angioedema (swelling of face, lips, tongue), vasculitis, hepatitis.

Serious Adverse Reactions and Safety Constraints

Regulatory documents highlight risks considered clinically significant, which include rare but serious adverse events and specific contraindications. Angioedema, a severe hypersensitivity reaction, is officially documented as a rare event. Changes in renal function and elevated hyperkalemia (high blood potassium levels) are noted, particularly in patients with pre-existing renal conditions or Type 2 diabetes with nephropathy.

Use of Losa is contraindicated during the second and third trimesters of pregnancy due to the risk of fetal toxicity. It is also contraindicated in individuals with severe hepatic impairment. Furthermore, symptomatic hypotension may occur, often documented as being more pronounced following the first dose or subsequent dose increase.

Overdose and Emergency Response

Overdose: Losa (Losartan)

This section summarizes officially documented information regarding Losa overdose, strictly based on authoritative government regulatory sources.

Documented Overdose Manifestations and Actions

The most likely manifestations of Losa overdose are consequences of its blood pressure-lowering effect. These documented clinical signs include hypotension (low blood pressure) and tachycardia (increased heart rate). Bradycardia (decreased heart rate) may also occur due to vagal stimulation.

Action/Status Official Regulatory Statement
Urgent Help Seek urgent medical attention if an overdose is suspected or occurs.
Primary Management Supportive treatment should be instituted for symptomatic hypotension; this includes placing the patient in a supine position and administering intravenous infusion of saline if marked hypotension is present.
Antidote/Removal No specific antidote exists. Losartan and its active metabolite are not removed by hemodialysis due to high plasma protein binding.

Population-Specific Considerations

For neonates who experienced in utero exposure, observation is recommended for potential hypotension, oliguria, and hyperkalemia.

Therapeutic Uses of Losa

Losartan (Losa) is commonly used in the management of several chronic cardiovascular and renal health domains, and may assist with providing long-term therapeutic support to patients. Clinical applications include its relevance for managing three key therapeutic areas.


Sustained Control and Protection

This medication is applied in addressing the symptoms related to systemic imbalance that stem from chronic high blood pressure in adults and pediatric patients. It is considered relevant for conditions where chronic hypertension is associated with specific complications, such as Left Ventricular Hypertrophy (LVH) or proteinuria in patients with Type 2 Diabetes. The benefit supports general well-being by assisting with easing the strain associated with severe health risks, and is relevant for easing symptoms associated with chronic heart failure.

“This therapy may assist with supportive relief when symptoms interfere with routine activities and general well-being, especially regarding long-term cardiovascular health.”

Quick Fact: Support for Systemic Imbalance Losartan helps manage the long-term strain of high blood pressure, contributing to improved day-to-day comfort and assisting with maintaining functional stability during symptomatic periods.

Regulatory References

  1. Official FDA-Approved Label on DailyMed

Eligibility and Restrictions for Use

Losartan (Losa) eligibility is defined by official regulatory documents based on a patient's age and specific clinical status. The medicine is contraindicated in several populations where use is strictly prohibited.

Contraindicated Population Regulatory Basis
Pregnancy Prohibited in the second and third trimesters due to the risk of fetal injury or death.
Severe Hepatic Impairment Prohibited due to significantly increased drug concentration (severe liver disease).
Dual RAAS Blockade Prohibited with Aliskiren in patients with diabetes mellitus or renal impairment (GFR lt 60 mL/ min/ 1.73 m^2).
Hypersensitivity Prohibited with known allergy to Losartan or any component of the formulation.

Age and Restricted Use

The medicine is approved for adults and for children aged 6 years and older for the treatment of hypertension. Use is not recommended in children under 6 years of age or in pediatric patients with very low renal function (GFR lt 30 mL/ min/ 1.73 m^2). Use is not recommended in nursing mothers. Patients with mild to moderate hepatic impairment or those who are volume- or salt-depleted require caution or condition correction before use, as noted in the official labeling.

What should I know about interactions with other medicines?

Interactions with other medicines and products

This section outlines interactions with Losartan potassium that are officially documented in government regulatory sources, classified by their nature and required restrictions.


Contraindicated Combinations

The co-administration of Losartan with Aliskiren is strictly contraindicated in patients diagnosed with Diabetes Mellitus or those with moderate-to-severe renal impairment.

Pharmacodynamic and Electrolyte Risk

Classification Interacting Agents Official Interaction Statement
Not Recommended Potassium-Sparing Diuretics (e.g., Spironolactone, Amiloride), Potassium Supplements, Potassium-Containing Salt Substitutes Increased risk of hyperkalemia (elevated serum potassium levels) due to additive effects.
Clinically Significant Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), including COX-2 Inhibitors May lead to attenuation of the blood pressure-lowering effect and an increased risk of worsening renal function.
Clinically Significant Lithium Can cause reversible increases in serum lithium concentrations and potential toxicity.
Additive Effect Other Antihypertensive Agents (e.g., ACE Inhibitors, Antipsychotics, Baclofen) May increase the risk of hypotension (low blood pressure).

Pharmacokinetic (Exposure-Altering) Interactions

Substances that modify the systemic exposure (AUC) of Losartan or its active metabolite via the CYP2C9 and CYP3A4 pathways are documented. For example, the strong CYP2C9 inhibitor Fluconazole increases Losartan exposure while reducing the exposure of its active metabolite. Conversely, CYP enzyme inducers such as Rifampin and Phenobarbital reduce the exposure of both Losartan and its active metabolite.

Food and Population Notes

Losartan may be administered with or without food as no clinically significant interaction is documented. The increased risk of adverse renal outcomes when combining Losartan with NSAIDs is specifically noted as being of greater concern in patients with poor pre-existing renal function.

Mechanism of Action

Losa (Losartan) is a selective and competitive Angiotensin II Type 1 ( AT1) receptor antagonist. The molecule, along with its active metabolite EXP3174, binds with high affinity to the AT1 receptor, primarily located on vascular smooth muscle, cardiac tissue, renal tissue, and the adrenal gland.

This antagonistic interaction prevents the binding and subsequent signaling of the endogenous ligand, Angiotensin II ( Ang II). Ang II binding to the AT1 receptor typically activates G q-protein-coupled pathways, which initiate the intracellular cascade involving Phospholipase C (PLC), generating Inositol Triphosphate (IP3) and Diacylglycerol (DAG). The downstream consequences of this pathway include increased intracellular calcium and subsequent vasoconstriction and aldosterone secretion.

By blocking the AT1 receptor, Losa interrupts this signal transduction. The cellular result is the inhibition of vascular smooth muscle contraction and the suppression of aldosterone release from the adrenal cortex. System-level physiological modulation involves a decrease in total peripheral resistance due to vasodilation and a reduction in fluid retention via diminished aldosterone-mediated sodium and water reabsorption in the renal tubules. This collectively modulates systemic blood pressure.

Dosage and Administration Information

How to Use Losa: Administration Guidelines

Losartan (Losa) is administered orally in accordance with prescribing information, which outlines the standardized routes, dosing, and schedule for its use. It is primarily available as film-coated tablets but can also be compounded into an oral suspension for specific patients.


Standard Dosing and Frequency

Losartan is typically dosed once daily.

Indication Standard Adult Starting Dose Maximum Recommended Daily Dose
Hypertension 50 mg 100 mg
Nephropathy in Type 2 Diabetes 50 mg 100 mg

The maximal antihypertensive effect is generally observed within 3 to 6 weeks after starting therapy, and the dosage may be adjusted (titrated) to the maximum dose at monthly intervals if required.


Administration Conditions and Adjustments

The tablets may be taken with or without food, offering flexibility in the daily administration schedule. The tablet should be swallowed whole with water.

Specific starting dose adjustments are required for certain populations to ensure proper use:

  • Hepatic Impairment: A lower initial dose of 25 mg once daily is specified for patients with known hepatic impairment.
  • Volume Depletion: An initial dose of 25 mg once daily is recommended for patients who are volume-depleted.
  • Pediatric Use: Dosing for children aged 6 to 16 years is weight-based, starting at 0.7 mg/kg once daily, up to a maximum total of 50 mg per day.

Recent Clinical Evidence

Research Evidence for High Blood Pressure (Hypertension)

Losa (Losartan) was studied for hypertension through Randomized Controlled Trials (RCTs), which are considered a high standard for medical research. These studies research has explored BP level changes in adults and children with essential hypertension. In addition to short-term BP control, large-scale, long-term RCTs monitored the occurrence rate of major cardiovascular (CV) events, such as stroke and heart attack (MI), when compared to other established treatments or inactive substances. The studies reported the observed rates of these events across the different groups, contributing to the broader evidence landscape for long-term cardiovascular outcomes.

Studies Tracking Structural Heart Protection (Left Ventricular Hypertrophy)

Research focused on monitoring a primary composite outcome that included fatal and non-fatal stroke, heart attack, and CV death in patients with hypertension alongside Left Ventricular Hypertrophy (LVH). The reports described the incidence rate of stroke compared to an active comparator. Regulatory analyses noted that the observed difference in stroke events compared to the active comparator was not consistent across all patient characteristics, specifically in the Black patient subgroup. Comparative evidence against all alternative LVH treatments is not directly available from this trial.

Kidney Research on Kidney Protection in Type 2 Diabetes

Research exploring Losartan's use in patients with Type 2 Diabetes and proteinuria monitored how often patients reached a specific renal endpoint, which included the doubling of serum creatinine, the development of end-stage renal disease (ESRD), or death. What remains uncertain is the benefit regarding all-cause mortality as a single component of the primary endpoint, which was not significantly established in the main trial. Data are still emerging regarding its use for primary prevention in earlier stages of Type 2 Diabetes.

What Research Gaps and Uncertainties Remain

Long-term effects are not fully established for certain outcomes, particularly hard CV or renal events in pediatric populations. Evidence quality varies across studies, and some pediatric evidence includes measuring surrogate markers (like protein levels) over limited follow-up durations rather than tracking long-term events.

Key Studies & References

  1. Label: LOSARTAN POTASSIUM tablet, film coated - DailyMed (FDA Regulatory Document)

Frequently Asked Questions (FAQ)

Common questions about Losa (FAQ)

Q: What happens if I accidentally miss a dose of Losa?

Official patient information often suggests taking the dose as soon as it is remembered. However, if it is already near the time for the next scheduled dose (usually the next day), regulatory guidance advises skipping the missed dose entirely and simply resuming the normal schedule. Information for patients advises against taking two doses at once to make up for a single missed dose.


Q: What are the official warnings about using Losa with alcohol?

Official warnings indicate that consuming alcohol can increase the blood pressure-lowering effect of Losartan. This increased effect may lead to symptoms such as dizziness or light-headedness. Official guidance suggests that patients may need to limit or avoid alcohol, especially when first starting treatment or increasing the dose.


Q: Is it necessary to take Losa at the exact same time every day?

Losartan is an oral tablet typically taken once a day and can be administered with or without food. Official guidance often recommends taking it around the same time every day, as this strategy helps maintain consistent blood levels of the medication. This practice supports effective management of your condition.


Q: Does Losa cause weight gain or weight loss?

The official regulatory labeling does not list general weight gain or weight loss as a common or rare side effect of Losartan. However, swelling due to fluid retention, known as edema, is a possible side effect of the medication. This fluid retention is known to cause a temporary increase in body weight.


Q: What happens if I stop taking Losa suddenly?

Abrupt discontinuation is not associated with a formal withdrawal syndrome or a sudden, severe spike in blood pressure. Nevertheless, stopping Losartan may cause blood pressure to increase over time, potentially raising the risk of serious cardiovascular events. Consultation with a healthcare professional is necessary before discontinuing treatment.


Q: Can older adults (seniors) safely take Losa?

Losartan is approved for use in adults, including older individuals. While no general dose adjustment is needed based solely on age, a specific lower initial starting dose (25 mg) is officially recommended for patients who may be volume-depleted or have certain liver conditions. Monitoring for low blood pressure may be needed in this population.


Q: Does Losa affect birth control effectiveness?

The official regulatory labeling does not report an interaction that affects the effectiveness of hormonal birth control pills. Furthermore, official information indicates no evidence to suggest that Losartan reduces fertility in either men or women.


Q: What should be done if a side effect of Losa seems to get worse?

If any side effect becomes severe or does not go away, or if any signs of a serious reaction occur (such as swelling of the face, lips, or throat), immediate contact with a healthcare professional or emergency medical services is necessary. This ensures prompt evaluation of the situation.


Q: Is Losa considered a first-line treatment for its indicated condition?

Clinical guidelines from authoritative bodies generally recognize Losartan, which belongs to the Angiotensin II Receptor Blocker (ARB) class, as one of the recommended first-line therapy options. It is used for treating high blood pressure (hypertension) alongside several other major classes of medication.


Q: What is the general duration of a course of treatment with Losa?

For its officially approved chronic conditions, such as hypertension and diabetic kidney disease, treatment with Losartan is typically long-term. As is common with such chronic medications, patients typically remain on treatment long-term, rather than completing a short course.


Q: Are generic versions of Losa available?

Yes, the medication known as Losa is available as the generic compound, Losartan Potassium. The first generic version of Losartan was approved for market use by the U.S. Food and Drug Administration (FDA) in 2010.


Q: Is Losa a new medicine or has it been available for a long time?

Losartan is not considered a new medicine in the market. It was patented in 1986 and received its initial approval for medical use in the United States in 1995. This indicates it has been available and well-established for several decades.


Q: What is the official guidance for handling an accidental overdose of Losa?

An overdose of Losartan is most likely to result in severe low blood pressure, known as hypotension. Symptoms of this condition can include dizziness, lightheadedness, or increased heart rate. Official guidance recommends that immediate medical assistance or emergency help should be sought if an overdose is suspected.


Q: Can Losa affect blood sugar levels?

Research indicates that Losartan generally has a neutral effect on the body's blood sugar (glucose) metabolism and may be associated with favorable trends compared to some other types of blood pressure medications. Official regulatory documents do not list high or low blood sugar as a common side effect.


Q: Is Losa classified as an addictive substance?

Losartan is a prescription medication but is not regulated under the Controlled Substances Act by the U.S. Drug Enforcement Administration (DEA). Therefore, it is not classified as an addictive substance or a drug of abuse.


Q: Why is Losa sometimes prescribed alongside other medications?

Losartan is frequently prescribed in combination with other medications, such as the diuretic hydrochlorothiazide. Combination therapy is commonly utilized when a single medication is not sufficient to achieve effective blood pressure control.


Q: What types of pre-screening tests are sometimes required before starting Losa?

Before starting and periodically during treatment with Losartan, blood tests are officially recommended for monitoring. These tests are used to check kidney function (such as creatinine and eGFR) and the patient's potassium levels in the blood.


Q: Can Losa be taken with common over-the-counter pain relievers?

Losartan has no known interaction with acetaminophen, a common pain reliever. However, other over-the-counter medications, specifically Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), may increase the risk of kidney problems and can reduce the effectiveness of Losartan. Use these types of pain relievers with caution.


Q: Are there any foods or beverages that interact with Losa?

Official information warns that grapefruit or grapefruit juice may reduce the effectiveness of Losartan, and therefore avoiding them is generally recommended. Additionally, supplements and products containing potassium, such as potassium-containing salt substitutes, should be avoided without consultation due to the risk of high potassium levels (hyperkalemia).


Q: Does Losa affect my ability to drive or operate machinery?

The official labeling advises caution when performing tasks such as driving or operating machinery. This is because dizziness or drowsiness may occasionally occur when taking any medication for high blood pressure, particularly when treatment is first started or when the dose is increased.


Q: Are there any reported long-term health risks associated with Losa?

Losartan is prescribed for the long-term benefit of reducing cardiovascular risks such as stroke and for protecting the kidneys. As part of this long-term management, the official documents highlight that ongoing periodic monitoring of kidney function and potassium levels is required to ensure continued safe use.


Q: Does Losa interact with herbal supplements like St. John's Wort?

Official regulatory warnings note that St. John's Wort may interact with Losartan by affecting the key enzymes (CYP2C9 and CYP3A4) that break down the medication. This potential interaction could lead to lower blood levels of Losartan, which may reduce its overall effectiveness.


Q: What body organs are listed as potentially being affected by Losa?

Losartan is officially indicated to protect the heart and kidneys in specific patient populations. However, the official labeling also includes warnings and precautions related to potential adverse effects on the kidneys (renal function deterioration) and the liver (hepatic impairment warnings).


Q: Is Losa safe for someone with a history of heart or kidney problems?

Losartan is indicated to treat certain heart and kidney conditions, but pre-existing severe congestive heart failure, severe kidney disease, or severe liver disease requires caution. In these cases, a lower starting dose and the need for close monitoring of kidney function and potassium levels are often officially recommended.


Q: Does Losa typically interact with common multivitamins?

There is no known general interaction with the basic ingredients of most common multivitamins. However, because the official labeling cautions against supplements containing potassium, it is prudent to check the ingredients of any multivitamin or mineral supplement, as some may contain potassium that could interact with Losartan.

How should Losa be stored and disposed of?

The official regulatory labeling for Losartan Potassium Tablets specifies precise requirements for storage and disposal to maintain product integrity and ensure safety.

Storage Conditions

Losartan Potassium Tablets must be stored at a Controlled Room Temperature, which is generally defined as 20 C to 25 C (68 F to 77 F). The medication must be protected from moisture and kept in its original container with the lid tightly closed. Storage outside of these mandated temperature and humidity conditions should be avoided.

️ Safety and Disposal

The tablets must be kept out of the sight and reach of children to prevent accidental ingestion. Disposal of unused or expired Losartan Potassium Tablets must be completed according to local regulations and official guidance. This protocol usually involves drug take-back programs, rather than discarding the tablets in household trash or pouring them down a drain.

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

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