Losartan 100mg 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, Angiotensin II Receptor Blocker (ARB)
Pharmacologic Class
Angiotensin II Receptor Antagonist
Pregnancy Category
Not applicable (FDA has moved to a narrative system, but historically Category D in 2nd/3rd trimester, C in 1st)
FDA Approved
Apr 1995
DEA Schedule
Not Controlled
Overview
What is this medicine?
Losartan is a medication used to treat high blood pressure. It works by relaxing blood vessels, which allows blood to flow more easily and lowers blood pressure. It's also used to protect kidneys in people with diabetes and high blood pressure, and to reduce the risk of stroke in certain patients.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication with or without food, as directed. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
If you have difficulty 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 the medication. If one is not provided, ask your pharmacist for a suitable measuring device.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light and moisture. Keep the container tightly closed and avoid storing it in a bathroom. If a liquid suspension is prepared from the tablets, store it in the refrigerator, but do not freeze. Discard any unused portion of the liquid suspension after 28 days.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and resume 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 use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication with or without food, as directed. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
If you have difficulty 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 the medication. If one is not provided, ask your pharmacist for a suitable measuring device.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light and moisture. Keep the container tightly closed and avoid storing it in a bathroom. If a liquid suspension is prepared from the tablets, store it in the refrigerator, but do not freeze. Discard any unused portion of the liquid suspension after 28 days.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and resume 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
- Continue to monitor blood pressure regularly at home.
- Maintain a healthy diet (e.g., low sodium, DASH diet).
- Engage in regular physical activity.
- Limit alcohol intake.
- Avoid potassium-rich salt substitutes unless advised by a doctor.
- Do not stop taking the medication abruptly without consulting your doctor.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
Hypertension: 50 mg orally once daily. May be increased to 100 mg once daily.
Dose Range:
25 - 100 mg
Condition-Specific Dosing:
diabeticNephropathy:
50 mg orally once daily, may be increased to 100 mg once daily based on blood pressure response.
strokeRiskReduction:
50 mg orally once daily, may be increased to 100 mg once daily based on blood pressure response.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Hypertension (≥6 years old): Initial 0.7 mg/kg orally once daily (up to 50 mg total). Max 1.4 mg/kg (up to 100 mg total) once daily.
Adolescent:
Hypertension (≥6 years old): Initial 0.7 mg/kg orally once daily (up to 50 mg total). Max 1.4 mg/kg (up to 100 mg total) once daily.
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment necessary.
Moderate:
No dosage adjustment necessary.
Severe:
No dosage adjustment necessary.
Dialysis:
No dosage adjustment necessary for patients on dialysis; Losartan and its active metabolite are not removed by hemodialysis.
Hepatic Impairment:
Mild:
Initial dose of 25 mg orally once daily.
Moderate:
Initial dose of 25 mg orally once daily.
Severe:
Initial dose of 25 mg orally once daily.
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). This blockade inhibits the vasoconstrictive and aldosterone-secreting effects of angiotensin II, leading to vasodilation, decreased peripheral resistance, and reduced blood pressure.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 33%
Tmax:
Losartan: 1 hour; Active metabolite (E-3174): 3-4 hours
FoodEffect:
Does not significantly affect the plasma concentration profile of losartan or its active metabolite.
Distribution:
Vd:
Losartan: 34 L; Active metabolite: 12 L
ProteinBinding:
Losartan: ≥98%; Active metabolite: ≥99%
CnssPenetration:
Limited
Elimination:
HalfLife:
Losartan: 2 hours; Active metabolite (E-3174): 6-9 hours
Clearance:
Losartan: 600 mL/min (renal 74 mL/min); Active metabolite: 50 mL/min (renal 26 mL/min)
ExcretionRoute:
Biliary/Fecal (approximately 58-60%), Renal/Urinary (approximately 35-43%)
Unchanged:
Losartan: Approximately 4% (urine); Active metabolite: Approximately 6% (urine)
Pharmacodynamics
OnsetOfAction:
Within 6 hours (for blood pressure reduction)
PeakEffect:
3-6 weeks (for full antihypertensive effect)
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
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency 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
+ Weakness
+ 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 symptoms that concern you or do not go away, contact your doctor:
Signs of a common cold
Dizziness, tiredness, or weakness
Diarrhea
Back pain
Stuffy nose
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency 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
+ Weakness
+ 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 symptoms that concern you or do not go away, contact your doctor:
Signs of a common cold
Dizziness, tiredness, or weakness
Diarrhea
Back pain
Stuffy nose
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult 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)
- Difficulty breathing or swallowing
- Signs of high potassium (e.g., unusual tiredness, weakness, irregular heartbeat, nausea)
- Signs of kidney problems (e.g., decreased urination, swelling in ankles/feet)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is crucial that you inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the symptoms you experienced.
If you have kidney problems, as this may affect how your body processes the medication.
If you are currently taking a medication that contains aliskiren and you also have diabetes or kidney problems.
For Parents or Guardians:
If your child is under 6 years of age, do not administer this medication. It is not approved for use in children younger than 6 years old.
Additional Considerations:
This list is not exhaustive, and it is essential to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. They will help determine if it is safe to take this medication with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is crucial that you inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the symptoms you experienced.
If you have kidney problems, as this may affect how your body processes the medication.
If you are currently taking a medication that contains aliskiren and you also have diabetes or kidney problems.
For Parents or Guardians:
If your child is under 6 years of age, do not administer this medication. It is not approved for use in children younger than 6 years old.
Additional Considerations:
This list is not exhaustive, and it is essential to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. They will help determine if it is safe to take this medication with your other medications and health conditions. 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 drug, 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 product, consult your doctor. Additionally, if you are on a low-salt or salt-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 or 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 breast-feeding, discuss the potential risks to your baby with your doctor.
When starting this drug, 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 product, consult your doctor. Additionally, if you are on a low-salt or salt-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 or 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 breast-feeding, discuss the potential risks to your baby with your doctor.
Overdose Information
Overdose Symptoms:
- Hypotension (low blood pressure)
- Tachycardia (rapid heartbeat)
- Bradycardia (slow heartbeat, less common)
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic. Hemodialysis is not effective.
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
- NSAIDs (including COX-2 inhibitors)
Moderate Interactions
- Other antihypertensives (additive effect)
- CYP2C9 inhibitors (e.g., fluconazole, amiodarone) - may decrease active metabolite formation
- CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) - may decrease active metabolite formation
- CYP2C9 inducers (e.g., rifampin) - may increase active metabolite formation
- Alcohol (may enhance hypotensive effect)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy.
Serum Creatinine (SCr) and Blood Urea Nitrogen (BUN)
Rationale: To assess baseline renal function, especially important in patients with pre-existing renal impairment or those at risk.
Timing: Prior to initiation of therapy.
Serum Potassium (K+)
Rationale: To assess baseline potassium levels, as ARBs can cause hyperkalemia.
Timing: Prior to initiation of therapy.
Liver Function Tests (LFTs)
Rationale: To assess baseline hepatic function, especially important as losartan is metabolized in the liver and dose adjustment is needed for hepatic impairment.
Timing: Prior to initiation of therapy (if hepatic impairment suspected or known).
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly (e.g., weekly after initiation/dose change, then monthly or every 3-6 months once stable)
Target: <130/80 mmHg (general target for hypertension, may vary based on comorbidities)
Action Threshold: Persistently elevated BP despite maximum dose, or symptomatic hypotension.
Serum Creatinine (SCr) and Blood Urea Nitrogen (BUN)
Frequency: Within 1-2 weeks after initiation or dose increase, then periodically (e.g., every 6-12 months) or more frequently in patients with renal impairment or on concomitant nephrotoxic drugs.
Target: Within patient's baseline range or acceptable limits.
Action Threshold: Significant increase (e.g., >30% above baseline or >0.5 mg/dL increase) or signs of acute kidney injury.
Serum Potassium (K+)
Frequency: Within 1-2 weeks after initiation or dose increase, then periodically (e.g., every 6-12 months) or more frequently in patients at risk for hyperkalemia (e.g., renal impairment, diabetes, concomitant potassium-sparing diuretics/supplements).
Target: 3.5-5.0 mEq/L
Action Threshold: >5.5 mEq/L or symptomatic hyperkalemia.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Fatigue
- Swelling (angioedema, though rare)
- Signs of hyperkalemia (e.g., muscle weakness, irregular heartbeat)
- Signs of renal dysfunction (e.g., decreased urine output, swelling)
Special Patient Groups
Pregnancy
Contraindicated in the second and third trimesters of pregnancy due to risk of fetal injury and death. Discontinue as soon as pregnancy is detected. First trimester exposure risk is less clear but generally avoided.
Trimester-Specific Risks:
First Trimester:
Limited human data, but animal data suggest potential risk. Generally avoided if possible, but risk is lower than later trimesters.
Second Trimester:
Significant risk of fetal renal dysfunction, oligohydramnios, fetal lung hypoplasia, skeletal deformations, and death.
Third Trimester:
Significant risk of fetal renal dysfunction, oligohydramnios, fetal lung hypoplasia, skeletal deformations, and death.
Lactation
Not recommended during breastfeeding. Losartan and its active metabolite are excreted into breast milk in rats, and it is unknown if they are 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:
Potential for serious adverse effects (e.g., hypotension, renal effects).
Pediatric Use
Approved for hypertension in children 6 years and older. Safety and efficacy not established in children younger than 6 years or for indications other than hypertension.
Geriatric Use
No overall differences in efficacy or safety have been observed between elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. No specific dose adjustment is typically needed based solely on age, but consider potential for decreased renal/hepatic function and polypharmacy.
Clinical Information
Clinical Pearls
- Losartan is a prodrug, converted to its more potent active metabolite E-3174.
- It is often preferred over ACE inhibitors for patients who develop cough with ACE inhibitors, as ARBs do not inhibit bradykinin breakdown.
- Monitor potassium levels, especially in patients with renal impairment, diabetes, or those on potassium-sparing diuretics/supplements.
- Advise patients to avoid sudden changes in position to minimize orthostatic hypotension.
- Full antihypertensive effect may take 3-6 weeks to achieve.
- Contraindicated with aliskiren in diabetic patients or those with moderate-to-severe renal impairment.
Alternative Therapies
- Other Angiotensin Receptor Blockers (ARBs): Valsartan, Candesartan, Irbesartan, Olmesartan, Telmisartan, Azilsartan
- ACE Inhibitors: Lisinopril, Enalapril, Ramipril, Captopril
- Calcium Channel Blockers (CCBs): Amlodipine, Nifedipine, Diltiazem, Verapamil
- Thiazide Diuretics: Hydrochlorothiazide, Chlorthalidone
- Beta-blockers: Metoprolol, Atenolol, Carvedilol
- Direct Renin Inhibitors: Aliskiren
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (100mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea 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, including the amount taken and the time it happened, to facilitate prompt and appropriate care.