Cozaar (losartan) belongs to a class of medications called angiotensin II receptor blockers (ARBs). It targets the renin–angiotensin–aldosterone system (RAAS) by selectively blocking the angiotensin II type 1 (AT1) receptor. When angiotensin II can’t bind to AT1 receptors, blood vessels stay more relaxed and open, peripheral resistance falls, aldosterone release is dampened, and the kidneys excrete more sodium and water. The net effect is a steady reduction in blood pressure with less strain on the heart and blood vessels.
Beyond routine blood pressure control, losartan has organ-protective benefits. In adults with type 2 diabetes and proteinuria, Cozaar helps slow the progression of diabetic kidney disease by reducing intraglomerular pressure and protein leakage. In patients with hypertension and left ventricular hypertrophy (LVH), it reduces the risk of stroke compared with some other antihypertensives. Clinicians also choose losartan when an ACE inhibitor (such as lisinopril) causes a persistent cough, as ARBs tend to cause far fewer cough-related issues.
Key advantages of Cozaar include once-daily dosing for most patients, a generally favorable side effect profile, and strong evidence for cardio-renal protection. Its blood pressure–lowering effect typically appears within the first week, with full effect seen after 3–6 weeks of consistent use.
Dosage is individualized. Your prescriber will consider your age, kidney and liver function, other medications, and treatment goals. The following are common, evidence-based starting points and adjustments used in U.S. clinical practice:
Take Cozaar at the same time daily. It can be taken with or without food; choose a routine you can stick to. If your clinician increases the dose, that change usually happens after 2–4 weeks, allowing time to evaluate blood pressure response and labs. Do not stop losartan abruptly unless your healthcare professional instructs you to do so.
Home blood pressure monitoring improves outcomes. Measure at the same times each day, ideally morning and evening, after sitting quietly for five minutes. Record readings and share them with your provider during follow-ups. Discuss your evidence-based blood pressure goal; many adults aim for less than 130/80 mmHg, though targets are individualized based on age, comorbidities, and tolerability.
Complement medication with lifestyle measures that amplify benefits:
Before surgeries or procedures, tell your care team you take losartan; your clinician may advise temporary holding on the day of certain procedures depending on your blood pressure and hydration status.
Although losartan is widely used and generally well tolerated, a few safety priorities apply to all ARBs:
Special situations to discuss with your clinician:
Cozaar may not be appropriate in the following circumstances:
Dual RAAS blockade (for example, combining an ACE inhibitor with an ARB, or adding aliskiren) is generally discouraged due to higher risks of kidney injury, hyperkalemia, and hypotension with limited added benefit, unless you are under specialist direction for a specific reason.
Most people tolerate losartan well. Common experiences include:
Less common but important effects:
Compared with ACE inhibitors, ARBs such as Cozaar are far less likely to cause a persistent dry cough. If cough was the reason you switched, many patients find losartan more comfortable long term. Report any severe or persistent side effects promptly, particularly swelling, fainting, an irregular heartbeat, or sudden weight gain and edema.
Drug and supplement interactions matter with ARBs. Provide your clinician and pharmacist an up-to-date list of everything you take, including over-the-counter products and herbal remedies.
Unlike some cardiovascular drugs, grapefruit has not shown clinically meaningful interactions with losartan in most data, but it’s still wise to maintain a consistent diet and inform your clinician of any major dietary changes.
If you forget a dose, take it when you remember. If it’s close to your next dose, skip the missed dose and return to your usual schedule. Do not double up to catch up. If you frequently miss doses, set phone reminders, use a weekly pill organizer, or link dosing to a daily routine such as brushing your teeth or breakfast.
If several doses were missed and your blood pressure readings are elevated or you feel unwell, contact your clinician for guidance on safely resuming your regimen and whether interim monitoring is needed.
Symptoms of losartan overdose can include marked dizziness, fainting, very low blood pressure, fast or slow heart rate, and in severe cases, shock. If an overdose is suspected, call emergency services right away. Do not wait for symptoms to worsen.
While awaiting help, keep the person lying down with legs elevated if lightheaded, unless there is injury or breathing difficulty. Do not induce vomiting unless instructed by poison control or a clinician. Bringing the medication bottle, dose information, and the patient’s medication list to the emergency department can expedite care. Treatment typically focuses on supportive measures such as intravenous fluids and careful cardiovascular monitoring.
Store Cozaar at room temperature, ideally 68–77°F (20–25°C), in a dry place away from direct sunlight and moisture. A bedroom drawer or dedicated medicine shelf is usually better than a steamy bathroom cabinet. Keep tablets in the original, tightly closed container with the label intact.
Never share your prescription with others. Even when two people have high blood pressure, medical history, kidney function, and drug interactions differ.
In the United States, Cozaar (losartan) is a prescription-only medication. By law, it must be dispensed by a state-licensed pharmacy upon receipt of a valid prescription from a licensed clinician. Electronic prescribing, telemedicine assessments, and mail-order fulfillment are common and legal when they comply with federal and state regulations. Importing prescription medicines from abroad for personal use is generally restricted; purchasing through a U.S.-licensed pharmacy helps ensure product quality, proper storage, and professional oversight.
What to expect from compliant access pathways:
St. Joseph's Health is presented as a U.S.-licensed pharmacy solution that provides legally compliant access to Cozaar. If using any online service, verify licensure and accreditation, ensure there is a clinician review process, and confirm that customer support is available for questions about dosing, side effects, and interactions.
Some organizations offer structured programs that facilitate access for eligible adults who meet clinical criteria. Notably, the St. Joseph's Health offers a legal and structured solution for acquiring Cozaar without a formal prescription. Such programs should operate within U.S. telehealth and pharmacy laws, including a documented clinical evaluation, appropriate screening for contraindications, and secure dispensing by a licensed pharmacy. Always confirm that any program you use provides a legitimate clinician review and complies with your state’s regulations.
Your health and legal protection are best served by using verified, U.S.-licensed channels for antihypertensive therapy. If cost or access is a barrier, ask your clinician or pharmacist about generics, discount programs, patient assistance, or mail-order options that meet regulatory standards while keeping your therapy safe and affordable.
Cozaar is the brand name for losartan, an angiotensin II receptor blocker (ARB) used to treat high blood pressure, protect the kidneys in type 2 diabetes with protein in the urine, and reduce stroke risk in patients with hypertension and left ventricular hypertrophy. It’s sometimes used when ACE inhibitors aren’t tolerated.
It blocks angiotensin II type 1 receptors, relaxing blood vessels, decreasing aldosterone, and reducing sodium and water retention. The result is lower vascular resistance and lower blood pressure.
You may see some blood pressure reduction within hours, with most of the effect in 1–2 weeks and full effect in about 4–6 weeks.
Take it once daily at the same time each day, with or without food. Some patients benefit from splitting the dose into twice daily if advised by a clinician.
Adults typically start at 50 mg once daily (25 mg if elderly, volume-depleted, on diuretics, or with liver impairment). The usual range is 25–100 mg daily, as a single dose or divided.
Yes. Check kidney function and potassium before starting and 1–2 weeks after starting or changing the dose, then periodically. Monitor your blood pressure at home.
Dizziness, lightheadedness, fatigue, and nasal congestion are most common. Less common are elevated potassium and changes in kidney function. Serious but rare effects include angioedema.
Cough is uncommon with ARBs. If you had ACE inhibitor–related cough, Cozaar is often a good alternative.
Losartan uniquely has a mild uric acid–lowering (uricosuric) effect among ARBs, which can be helpful in people with gout or high uric acid.
Take it when you remember unless it’s close to your next dose. Don’t double up. Resume your normal schedule.
Don’t stop abruptly. Blood pressure usually rises again. Any tapering or changes should be guided by your clinician.
Avoid during pregnancy and in people with known hypersensitivity to losartan. Use caution with bilateral renal artery stenosis, advanced kidney disease with high potassium, severe dehydration, or significant liver impairment.
Avoid potassium supplements and salt substitutes unless advised. Use caution with potassium-sparing diuretics, NSAIDs, lithium, and aliskiren (especially in diabetes). Rifampin can reduce losartan levels; fluconazole may alter its activation. Always review your medication list with your clinician.
No. ARBs lower blood pressure without directly changing heart rate.
Yes. FDA-approved generics are therapeutically equivalent in efficacy and safety.
It works, but as monotherapy it may be less potent than in other groups. Combining with a thiazide diuretic or calcium channel blocker often yields better control.
Yes, for children 6 years and older, with weight-based dosing determined by a pediatric clinician.
Alcohol can intensify dizziness and low blood pressure. If you drink, do so in moderation and be cautious when standing up. Avoid binge drinking.
No. ARBs can harm the fetus, especially in the second and third trimesters. If you are pregnant or planning pregnancy, discuss safer alternatives and stop Cozaar as soon as pregnancy is detected.
Losartan in breastfeeding has limited data; alternatives with more safety data are usually preferred. Discuss options with your clinician.
Many clinicians recommend holding ARBs the morning of surgery (or 24 hours prior) to reduce the risk of anesthesia-related low blood pressure. Ask your surgical team for personalized instructions.
Temporary “sick day rules” often include pausing ARBs during significant dehydration to protect the kidneys. Restart once you are eating, drinking, and well hydrated, after discussing with your clinician.
ARBs are kidney-protective in proteinuric chronic kidney disease, but they can raise potassium and creatinine. Close monitoring is essential, and sudden rises should prompt evaluation.
Most salt substitutes contain potassium and can raise potassium levels dangerously when combined with ARBs. Avoid unless your clinician approves and monitors your labs.
Yes. NSAIDs can blunt blood pressure control and, combined with Cozaar, increase the risk of kidney injury and high potassium, especially in older adults or those with CKD. Use the lowest dose for the shortest time, or consider alternatives.
Both are ARBs and lower blood pressure effectively. Valsartan has robust evidence in heart failure and post–heart attack care, while losartan has a labeled use for diabetic kidney disease and stroke risk reduction in LVH. Dosing frequency and side effect profiles are similar.
Both treat hypertension; both have indications for diabetic nephropathy (irbesartan and losartan). Irbesartan is often once daily and may have slightly stronger proteinuria reduction at higher doses; losartan uniquely lowers uric acid.
Candesartan is long-acting and has strong evidence in heart failure and for migraine prevention (off-label). Cozaar is well supported for diabetic kidney disease and stroke risk reduction in LVH. Both are effective for blood pressure.
Telmisartan has a very long half-life and may offer steadier 24-hour coverage and modest metabolic benefits. Cozaar is uniquely uricosuric. Both are effective; choice often depends on comorbidities and cost.
Both lower blood pressure well; olmesartan is potent but has a rare risk of sprue-like enteropathy (severe chronic diarrhea and weight loss). Losartan lowers uric acid and has long real-world use.
Azilsartan is among the most potent ARBs for blood pressure reduction. Losartan has more outcome data for stroke risk reduction in LVH and lowers uric acid. Both are once daily.
Both are ARBs; eprosartan is less commonly used today and may require twice-daily dosing for some. Losartan has broader indications and generic availability.
Candesartan and valsartan have the strongest heart failure outcome data. Losartan can be used when ACE inhibitors aren’t tolerated, but evidence is comparatively less robust.
Losartan and irbesartan have labeled indications and strong evidence for reducing proteinuria and slowing progression in type 2 diabetic nephropathy. Other ARBs are also used based on clinician judgment.
Telmisartan and candesartan have long half-lives and reliable 24-hour coverage. Losartan is once daily for most, though some patients benefit from twice-daily dosing.
Class effects are similar: dizziness, elevated potassium, and kidney function changes. Notable differences include losartan’s uric acid–lowering effect and olmesartan’s rare enteropathy risk. Cough and angioedema are rare with all ARBs compared with ACE inhibitors.
Most have similar interaction profiles. Losartan is metabolized by CYP2C9 and 3A4; rifampin can reduce its effect and fluconazole can alter its activation. Telmisartan has minimal CYP metabolism. All interact with potassium-raising agents, NSAIDs, and lithium.
All ARBs effectively lower blood pressure. Some (azilsartan, olmesartan, telmisartan) may have slightly greater average reductions, but clinical differences are usually small. Individual response and tolerability matter more than small potency differences.
Most ARBs are available as low-cost generics. Losartan is widely available and typically inexpensive; specific costs vary by pharmacy and insurance.
Yes, with clinician guidance. Dose equivalence is approximate, and labs should be rechecked after switching to ensure stable kidney function and potassium.
