Losartan 25mg Tablets
WARNING: Do not take if you are pregnant. Use during pregnancy may cause birth defects or loss of the unborn baby. If you get pregnant or plan on getting pregnant while taking this drug, call your doctor right away. @ COMMON USES: It is used to treat high blood pressure.It is used to protect kidney function in patients with diabetes who have protein loss.It is used to lower the chance of stroke in people with high blood pressure and a heart problem called left ventricular hypertrophy. This drug may not help lower the chance of stroke in Black patients with these health problems.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antihypertensive
Pharmacologic Class
Angiotensin II Receptor Blocker (ARB)
Pregnancy Category
Category D
FDA Approved
Apr 1995
DEA Schedule
Not Controlled
Overview
What is this medicine?
Losartan is a medication used to lower high blood pressure (hypertension) and to protect the kidneys in people with type 2 diabetes and high blood pressure. It works by relaxing blood vessels, allowing blood to flow more easily.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
If you have trouble swallowing pills, your doctor or pharmacist can help you prepare a liquid suspension. If a liquid suspension is prepared, make sure to shake it well before each use. When measuring liquid doses, use the measuring device that comes with your medication. If one is not provided, ask your pharmacist for a suitable measuring device.
Storing and Disposing of Your Medication
To keep your medication effective, store it at room temperature, away from light and moisture. Keep the container tightly closed and avoid storing it in a bathroom. If a liquid suspension is prepared from tablets, store it in the refrigerator, but do not freeze. Discard any unused portion of the liquid suspension after 28 days.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed dose.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
If you have trouble swallowing pills, your doctor or pharmacist can help you prepare a liquid suspension. If a liquid suspension is prepared, make sure to shake it well before each use. When measuring liquid doses, use the measuring device that comes with your medication. If one is not provided, ask your pharmacist for a suitable measuring device.
Storing and Disposing of Your Medication
To keep your medication effective, store it at room temperature, away from light and moisture. Keep the container tightly closed and avoid storing it in a bathroom. If a liquid suspension is prepared from tablets, store it in the refrigerator, but do not freeze. Discard any unused portion of the liquid suspension after 28 days.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed dose.
Lifestyle & Tips
- Take medication exactly as prescribed, usually once daily, with or without food.
- Do not stop taking Losartan without consulting your doctor, even if you feel well.
- Monitor your blood pressure regularly at home if advised by your doctor.
- Limit sodium intake in your diet.
- Engage in regular physical activity as recommended by your doctor.
- Maintain a healthy weight.
- Avoid potassium supplements or salt substitutes containing potassium unless specifically advised by your doctor.
- Avoid alcohol or limit intake, as it can further lower blood pressure.
- Inform your doctor if you become pregnant or plan to become pregnant, as this medication can harm the fetus.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
50 mg once daily
Dose Range:
25 - 100 mg
Condition-Specific Dosing:
hypertension:
Initial dose 50 mg once daily; can be increased to 100 mg once daily or decreased to 25 mg once daily. Max 100 mg/day.
diabetic_nephropathy:
Initial dose 50 mg once daily; can be increased to 100 mg once daily based on blood pressure response.
heart_failure:
Initial dose 12.5 mg once daily; titrate to 25 mg, 50 mg, 100 mg, or 150 mg once daily as tolerated, usually at weekly intervals.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Hypertension (6 years and older): Initial dose 0.7 mg/kg once daily (up to 50 mg total); adjust dose based on response. Max 1.4 mg/kg or 100 mg total daily dose.
Adolescent:
Hypertension (6 years and older): Initial dose 0.7 mg/kg once daily (up to 50 mg total); adjust dose based on response. Max 1.4 mg/kg or 100 mg total daily dose.
Dose Adjustments
Renal Impairment:
Mild:
No initial dosage adjustment needed.
Moderate:
No initial dosage adjustment needed.
Severe:
Consider lower initial dose (e.g., 25 mg once daily) if volume depleted or on dialysis, but generally no specific adjustment for renal impairment alone.
Dialysis:
Losartan and its active metabolite are not removed by hemodialysis. No specific dose adjustment for patients on dialysis, but monitor blood pressure and potassium closely.
Hepatic Impairment:
Mild:
Consider lower initial dose (e.g., 25 mg once daily).
Moderate:
Consider lower initial dose (e.g., 25 mg once daily).
Severe:
Not recommended in severe hepatic impairment due to significantly increased plasma concentrations.
Pharmacology
Mechanism of Action
Losartan is an angiotensin II receptor blocker (ARB). It selectively blocks the binding of angiotensin II to the AT1 receptor found in many tissues (e.g., vascular smooth muscle, adrenal gland, kidney, and heart). This blockade inhibits the vasoconstrictive and aldosterone-secreting effects of angiotensin II, leading to vasodilation, decreased peripheral vascular resistance, and reduced blood pressure. It does not inhibit ACE, thus avoiding the bradykinin-related side effects (e.g., cough) associated with ACE inhibitors.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 33%
Tmax:
Losartan: 1 hour; Active metabolite (E-3174): 3-4 hours
FoodEffect:
Does not significantly affect the Cmax or AUC of losartan or its active metabolite, but may slightly delay Tmax.
Distribution:
Vd:
Losartan: 34 L; Active metabolite: 12 L
ProteinBinding:
Losartan: Approximately 98.7%; Active metabolite: Approximately 99.8%
CnssPenetration:
Limited
Elimination:
HalfLife:
Losartan: 2 hours; Active metabolite (E-3174): 6-9 hours
Clearance:
Losartan: 600 mL/min (renal 50 mL/min); Active metabolite: 50 mL/min (renal 26 mL/min)
ExcretionRoute:
Biliary/fecal (approximately 58-60%) and renal (approximately 35-43%)
Unchanged:
Losartan: Approximately 4% (urine); Active metabolite: Approximately 6% (urine)
Pharmacodynamics
OnsetOfAction:
Within 6 hours
PeakEffect:
3-6 weeks for full antihypertensive effect (though initial effect seen within 1 week)
DurationOfAction:
24 hours
Safety & Warnings
BLACK BOX WARNING
When pregnancy is detected, discontinue Losartan as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Signs of high potassium levels, such as:
+ Abnormal heartbeat
+ Confusion
+ Weakness, lightheadedness, or dizziness
+ Feeling like passing out
+ Numbness or tingling
+ Shortness of breath
Signs of low blood sugar, including:
+ Dizziness
+ Headache
+ Feeling sleepy or weak
+ Shaking
+ Rapid heartbeat
+ Confusion
+ Hunger
+ Sweating
Severe dizziness or fainting
Chest pain
Swelling in the arms or legs
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help if they bother you or do not go away:
Signs of a common cold
Feeling dizzy, tired, or weak
Diarrhea
Back pain
Stuffy nose
Reporting Side Effects
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Signs of high potassium levels, such as:
+ Abnormal heartbeat
+ Confusion
+ Weakness, lightheadedness, or dizziness
+ Feeling like passing out
+ Numbness or tingling
+ Shortness of breath
Signs of low blood sugar, including:
+ Dizziness
+ Headache
+ Feeling sleepy or weak
+ Shaking
+ Rapid heartbeat
+ Confusion
+ Hunger
+ Sweating
Severe dizziness or fainting
Chest pain
Swelling in the arms or legs
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help if they bother you or do not go away:
Signs of a common cold
Feeling dizzy, tired, or weak
Diarrhea
Back pain
Stuffy nose
Reporting Side Effects
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or fainting (signs of low blood pressure)
- Swelling of the face, lips, tongue, or throat (signs of angioedema, a serious allergic reaction)
- Difficulty breathing or swallowing
- Signs of high potassium (e.g., unusual tiredness, muscle weakness, slow or irregular heartbeat)
- Signs of kidney problems (e.g., swelling in hands/feet, decreased urination)
- Persistent cough (less common than with ACE inhibitors, but possible)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Existing kidney problems, as this may affect the safety and efficacy of the medication.
* If you are taking a medication that contains aliskiren, particularly if you have diabetes or kidney problems.
Special Considerations for Children:
If your child is under 6 years of age, do not administer this medication, as it is not recommended for children younger than 6 years old.
Additional Precautions:
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. This will help ensure that it is safe to take this medication in conjunction with your other treatments. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Existing kidney problems, as this may affect the safety and efficacy of the medication.
* If you are taking a medication that contains aliskiren, particularly if you have diabetes or kidney problems.
Special Considerations for Children:
If your child is under 6 years of age, do not administer this medication, as it is not recommended for children younger than 6 years old.
Additional Precautions:
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. This will help ensure that it is safe to take this medication in conjunction with your other treatments. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
When starting this medication, avoid driving and other activities that require alertness until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position, and be cautious when climbing stairs.
Follow your doctor's instructions for monitoring your blood pressure and undergo blood tests as recommended. Discuss any concerns or questions with your doctor.
If you are using a salt substitute containing potassium, a potassium-sparing diuretic, or a potassium supplement, consult your doctor. Additionally, if you are on a low-sodium or sodium-free diet, discuss this with your doctor.
When taking this medication for high blood pressure, consult your doctor before using over-the-counter (OTC) products that may increase blood pressure, such as cough and cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids.
Before consuming alcohol, talk to your doctor. In hot weather or during physical activity, be cautious and drink plenty of fluids to prevent dehydration.
If you experience excessive sweating, fluid loss, vomiting, or diarrhea, inform your doctor, as these symptoms may lead to low blood pressure.
If you are breastfeeding, discuss the potential risks to your baby with your doctor.
When starting this medication, avoid driving and other activities that require alertness until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position, and be cautious when climbing stairs.
Follow your doctor's instructions for monitoring your blood pressure and undergo blood tests as recommended. Discuss any concerns or questions with your doctor.
If you are using a salt substitute containing potassium, a potassium-sparing diuretic, or a potassium supplement, consult your doctor. Additionally, if you are on a low-sodium or sodium-free diet, discuss this with your doctor.
When taking this medication for high blood pressure, consult your doctor before using over-the-counter (OTC) products that may increase blood pressure, such as cough and cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids.
Before consuming alcohol, talk to your doctor. In hot weather or during physical activity, be cautious and drink plenty of fluids to prevent dehydration.
If you experience excessive sweating, fluid loss, vomiting, or diarrhea, inform your doctor, as these symptoms may lead to low blood pressure.
If you are breastfeeding, discuss the potential risks to your baby with your doctor.
Overdose Information
Overdose Symptoms:
- Hypotension (low blood pressure)
- Tachycardia (rapid heart rate)
- Bradycardia (slow heart rate, less common)
What to Do:
Call 911 or your local emergency number immediately. For non-emergencies, call Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic. If ingestion is recent, gastric lavage may be considered. Intravenous fluids may be administered to correct hypotension.
Drug Interactions
Contraindicated Interactions
- Aliskiren (in patients with diabetes or renal impairment [GFR <60 mL/min/1.73 m2])
Major Interactions
- Potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride)
- Potassium supplements
- Salt substitutes containing potassium
- Lithium (increased serum lithium concentrations and toxicity)
- NSAIDs (including selective COX-2 inhibitors) - may attenuate antihypertensive effect and increase risk of renal impairment, especially in elderly, volume-depleted, or those with pre-existing renal dysfunction.
Moderate Interactions
- Other antihypertensive agents (additive hypotensive effect)
- CYP2C9 inhibitors (e.g., fluconazole) - may decrease active metabolite formation and increase losartan exposure.
- CYP2C9 inducers (e.g., rifampin) - may decrease losartan exposure and increase active metabolite formation.
- Trimethoprim (increased risk of hyperkalemia)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation
Serum Creatinine (SCr) and Blood Urea Nitrogen (BUN)
Rationale: To assess baseline renal function, as ARBs can affect renal hemodynamics.
Timing: Prior to initiation
Serum Potassium (K+)
Rationale: To assess baseline potassium levels, as ARBs can cause hyperkalemia.
Timing: Prior to initiation
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly, especially after dose adjustments (e.g., 1-2 weeks after adjustment) and then periodically (e.g., every 3-6 months) once stable.
Target: <130/80 mmHg (general target, may vary based on comorbidities)
Action Threshold: If BP remains uncontrolled, consider dose increase or add-on therapy. If hypotensive, consider dose reduction.
Serum Creatinine (SCr) and Blood Urea Nitrogen (BUN)
Frequency: 1-2 weeks after initiation or dose increase, then periodically (e.g., every 6-12 months) or as clinically indicated, especially in patients with pre-existing renal impairment or those on concomitant nephrotoxic drugs.
Target: Stable or within acceptable limits for patient's baseline.
Action Threshold: Significant increase (>30% from baseline or rapid rise) may indicate acute kidney injury; consider dose reduction or discontinuation.
Serum Potassium (K+)
Frequency: 1-2 weeks after initiation or dose increase, then periodically (e.g., every 6-12 months) or as clinically indicated, especially in patients with renal impairment, diabetes, or those on potassium-sparing diuretics/supplements.
Target: 3.5-5.0 mEq/L
Action Threshold: If K+ >5.5 mEq/L, consider dose reduction, discontinuation, or management of hyperkalemia.
Symptom Monitoring
- Dizziness or lightheadedness (especially upon standing, indicative of hypotension)
- Fatigue
- Signs of hyperkalemia (e.g., muscle weakness, irregular heartbeat, paresthesias)
- Signs of angioedema (e.g., swelling of face, lips, tongue, throat, difficulty breathing or swallowing)
- Signs of renal dysfunction (e.g., decreased urine output, swelling in ankles/feet)
Special Patient Groups
Pregnancy
Losartan is contraindicated in the second and third trimesters of pregnancy due to the risk of fetal injury and death. Exposure during the first trimester should also be avoided if possible, as there is emerging evidence of risk.
Trimester-Specific Risks:
First Trimester:
Emerging evidence suggests potential risk of major congenital malformations (e.g., cardiovascular, central nervous system) with first-trimester exposure to ARBs, though data are limited and conflicting. Discontinue as soon as pregnancy is detected.
Second Trimester:
Significant risk of fetal injury and death, including fetal renal dysfunction, oligohydramnios, fetal lung hypoplasia, skeletal deformations, and neonatal death.
Third Trimester:
Significant risk of fetal injury and death, including fetal renal dysfunction, oligohydramnios, fetal lung hypoplasia, skeletal deformations, and neonatal death.
Lactation
Not recommended during breastfeeding. Losartan and its active metabolite are excreted into the milk of lactating rats. It is unknown if losartan is excreted in human milk. Due to the potential for serious adverse effects in the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
Risk level L3 (Moderately Safe) - caution advised. Potential for hypotension, hyperkalemia, and renal effects in the infant.
Pediatric Use
Approved for hypertension in children 6 years and older. Safety and efficacy in children younger than 6 years have not been established. Dosing is weight-based. Monitor blood pressure, renal function, and potassium.
Geriatric Use
No specific dosage adjustment is generally required based on age alone. However, elderly patients may be more sensitive to the hypotensive effects and may have age-related decreases in renal function, requiring closer monitoring of blood pressure, renal function, and electrolytes.
Clinical Information
Clinical Pearls
- Losartan is often preferred over ACE inhibitors for patients who develop a cough with ACE inhibitors, as it does not inhibit bradykinin breakdown.
- Full antihypertensive effect may take 3-6 weeks to achieve, so dose adjustments should not be made too frequently.
- Educate patients about the risk of hyperkalemia, especially if they are also taking potassium supplements, potassium-sparing diuretics, or salt substitutes.
- Always check for pregnancy status in women of childbearing potential before initiating Losartan and advise on effective contraception.
- Monitor renal function and potassium closely, especially in patients with pre-existing renal impairment, heart failure, or those on concomitant NSAIDs.
Alternative Therapies
- ACE inhibitors (e.g., lisinopril, enalapril)
- Calcium Channel Blockers (e.g., amlodipine, nifedipine)
- Thiazide diuretics (e.g., hydrochlorothiazide, chlorthalidone)
- Beta-blockers (e.g., metoprolol, carvedilol)
- Direct Renin Inhibitors (e.g., aliskiren - limited use)
Cost & Coverage
Average Cost:
$10 - $30 per 30 tablets (25mg generic)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (preferred generic) or Tier 2 (non-preferred generic/brand)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.