Olmesartan is prescribed to treat primary (essential) hypertension in adults and in pediatric patients aged 6 years and older. Lowering elevated blood pressure reduces the risk of strokes, heart attacks, heart failure, and kidney complications over time. As an ARB, Olmesartan is often selected for patients who need once-daily control or who have previously experienced cough with an ACE inhibitor. Clinicians may use Olmesartan alone or as part of combination therapy with diuretics or calcium channel blockers when single-agent therapy is insufficient.
Beyond blood pressure numbers, the goal of Olmesartan therapy is long-term cardiovascular and renal protection. In patients with chronic kidney disease and albuminuria, guideline-based care often favors an ACE inhibitor or ARB to reduce proteinuria and slow progression, provided kidney function and potassium are closely monitored. Olmesartan’s smooth 24-hour coverage helps improve adherence and can be integrated into morning or evening routines with or without food.
Olmesartan selectively blocks angiotensin II type 1 (AT1) receptors, preventing angiotensin II—a potent vasoconstrictor—from tightening blood vessels and stimulating aldosterone release. The result is vasodilation, reduced sodium and water retention, and lower blood pressure. Initial effects are usually observed within 1–2 weeks, with full antihypertensive response often developing over 4–8 weeks. Because it doesn’t inhibit bradykinin breakdown, Olmesartan is less likely than ACE inhibitors to cause cough or angioedema, though angioedema can still rarely occur.
General adult dosing: The usual starting dose is 20 mg once daily, taken at the same time each day for consistency. Depending on blood pressure response after several weeks, the dose may be increased to 40 mg once daily, which is the typical maximum recommended dose. Some patients may begin at a lower dose based on clinical factors such as volume depletion, concomitant diuretic therapy, or advanced age. Olmesartan can be taken with or without food; pick a routine and stick with it.
Pediatric dosing (age 6–16): Dosing is weight-based and individualized by a clinician. For children who cannot swallow tablets, pharmacists can prepare an oral suspension using validated compounding procedures. For all pediatric patients, careful titration, blood pressure checks, and monitoring of kidney function and electrolytes are essential. Olmesartan is not generally used in children under 6 years for hypertension unless a specialist directs care.
Special populations: In patients with renal impairment, a lower starting dose and a reduced maximum dose may be appropriate, with close monitoring for rises in creatinine and potassium. For hepatic impairment, caution is warranted; clinicians may opt for lower doses and slower titration. In older adults, start low and titrate thoughtfully to limit orthostatic hypotension. If diuretics or other antihypertensives are added, reassess blood pressure and labs within 1–2 weeks to ensure safe response.
Pregnancy and breastfeeding: Olmesartan carries a boxed warning for fetal toxicity. Discontinue as soon as pregnancy is detected; ARBs can harm or terminate a developing fetus, particularly in the second and third trimesters. Discuss family planning and alternative therapies before starting. Olmesartan is generally not recommended during breastfeeding; your clinician can help weigh risks and choose safer options if needed.
Kidney function and potassium: ARBs can increase serum potassium (hyperkalemia) and, in susceptible individuals, lead to acute kidney injury—especially in dehydration, heart failure, bilateral renal artery stenosis, or with nephrotoxic drugs. Baseline and periodic monitoring of serum creatinine and electrolytes are critical. Volume depletion and low sodium states heighten the risk of symptomatic hypotension; correct these before starting. If you develop severe, chronic diarrhea and weight loss, contact your clinician promptly—rare sprue-like enteropathy has been reported with Olmesartan months to years after initiation.
Do not use Olmesartan during pregnancy. Avoid in patients with known hypersensitivity to Olmesartan or any component of the formulation. Concomitant use with aliskiren is contraindicated in people with diabetes due to increased risks of renal impairment, hyperkalemia, and hypotension; dual renin–angiotensin system (RAS) blockade with ACE inhibitors or ARBs is generally discouraged given limited additional benefit and higher adverse event rates. In patients with bilateral renal artery stenosis or severe renal impairment, use only with specialist guidance and close monitoring. History of angioedema requires caution; seek immediate care if swelling occurs.
Common adverse effects are typically mild and may include dizziness, headache, fatigue, or gastrointestinal upset. Because Olmesartan lowers blood pressure, some people—especially when dehydrated or taking diuretics—experience lightheadedness or orthostatic symptoms when standing quickly. Lab abnormalities can include increases in potassium and creatinine; most are modest but warrant attention, particularly in those with kidney disease or on interacting medications (e.g., potassium-sparing diuretics). Unlike ACE inhibitors, Olmesartan is unlikely to cause persistent cough.
Serious but uncommon reactions include severe hypotension, syncope, angioedema (tongue/lip/throat swelling), acute kidney injury, and rare sprue-like enteropathy presenting with chronic, severe diarrhea and weight loss—this can occur months to years after starting and may resolve upon discontinuation. Seek medical care urgently for facial or throat swelling, fainting, signs of high potassium (muscle weakness, abnormal heart rhythm), or persistent gastrointestinal symptoms. Report any unexpected or severe side effects to your clinician and pharmacist; adjustments or alternative therapies may be needed.
Potassium-elevating agents: Combining Olmesartan with potassium supplements, potassium-sparing diuretics (spironolactone, eplerenone, amiloride), or salt substitutes containing potassium increases the risk of hyperkalemia. If such combinations are medically necessary, monitor potassium closely. NSAIDs (e.g., ibuprofen, naproxen) may blunt the antihypertensive effect and, when combined with RAS inhibitors and diuretics, raise the risk of acute kidney injury—use the lowest effective NSAID dose for the shortest duration or consider alternatives.
Other considerations: Lithium levels can rise with ARBs, potentially causing toxicity; if coadministration can’t be avoided, monitor lithium levels. Avoid dual RAS blockade (ACE inhibitor + ARB or ARB + aliskiren) unless a specialist advises and monitors. Olmesartan has minimal cytochrome P450 metabolism, so it has fewer classic CYP interactions than some agents; however, additive blood pressure lowering occurs with other antihypertensives, alcohol, or drugs that impair autonomic responses. Always share a complete list of medications and supplements with your clinician and pharmacist.
If you miss a dose of Olmesartan, take it as soon as you remember the same day. If it’s almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not double up to “catch up.” To help prevent missed doses, pair your medication with a consistent daily routine or use reminders.
Olmesartan overdose may present with pronounced hypotension, dizziness, fainting, or rapid or slow heart rate. If an overdose is suspected, seek emergency medical attention and lie the person down with legs elevated until help arrives. Management is supportive: intravenous fluids, monitoring of blood pressure, heart rhythm, kidney function, and electrolytes. Because Olmesartan is highly protein-bound, hemodialysis is unlikely to remove it effectively. Bring all medication bottles so clinicians can verify ingested amounts.
Store Olmesartan tablets at room temperature (generally 20–25°C/68–77°F), protected from moisture and excessive heat. Keep in the original container with the lid tightly closed, and out of reach of children and pets. Do not use past the expiration date. If you receive a compounded suspension for pediatric use, follow the pharmacist’s storage and beyond-use date instructions carefully.
In the United States, Olmesartan is a prescription-only antihypertensive. You cannot legally buy Olmesartan without prescription. Any platform advertising the sale of prescription medications without a valid prescription is not compliant with U.S. law and may jeopardize your safety. A lawful, patient-centric pathway is to undergo a licensed clinical evaluation—either in person or via telehealth. HealthSouth MountainView provides structured care pathways where licensed clinicians review your history, assess your blood pressure, and, if appropriate, issue a valid prescription to be filled by a licensed pharmacy. This preserves safety, ensures correct dosing and monitoring, and keeps you within federal and state regulations.
Olmesartan is an angiotensin II receptor blocker (ARB) that relaxes blood vessels by blocking the angiotensin II hormone at its receptor. This reduces vascular resistance, lowers blood pressure, and eases the heart’s workload.
It is primarily prescribed for hypertension (high blood pressure) in adults and in certain children ages 6–16. It may be used alone or with other medications to reach target blood pressure.
Blood pressure starts to improve within 1 week, with full effect typically seen in 2–4 weeks of consistent daily use. Your clinician may adjust the dose after assessing response at 2–4 weeks.
Most adults start at 20 mg once daily; many require 20–40 mg once daily for optimal control. Take it at the same time each day, with or without food, and swallow tablets whole.
Choose the time you can be most consistent—morning or evening is fine. If your blood pressure rises overnight or early morning, your clinician may prefer bedtime dosing.
Dizziness, lightheadedness (especially after the first doses or dose increases), fatigue, and mild gastrointestinal upset can occur. Most effects are transient as your body adjusts.
Seek care for fainting, severe or persistent vomiting/diarrhea, signs of high potassium (muscle weakness, palpitations), significant decrease in urination, facial/lip swelling, or severe abdominal pain with chronic diarrhea and weight loss.
Rarely, olmesartan can cause severe chronic diarrhea, weight loss, and intestinal inflammation months or years after starting therapy. Symptoms usually resolve after stopping the drug; tell your clinician if you develop chronic diarrhea.
Do not use during pregnancy (boxed warning: can harm or kill an unborn baby). Avoid with aliskiren in patients with diabetes, and generally avoid dual renin-angiotensin blockade. Use caution or avoid in bilateral renal artery stenosis and in severe volume depletion.
Avoid or closely monitor with potassium-sparing diuretics, potassium supplements, and salt substitutes (hyperkalemia risk). NSAIDs can blunt blood pressure control and worsen kidney function; lithium levels can increase and become toxic.
Check blood pressure, kidney function (creatinine, eGFR), and potassium 1–2 weeks after starting or changing dose and periodically thereafter. Additional checks are needed if you add NSAIDs, diuretics, or potassium-raising agents.
Limit alcohol, which can amplify dizziness and lower blood pressure too much. Avoid dehydration, excessive heat, and high-potassium salt substitutes.
Take it when you remember the same day. If it is close to your next dose, skip the missed dose—do not double up.
By controlling hypertension, it reduces the risk of stroke, heart attack, and heart failure. As an ARB, it can help protect kidney function, particularly in people with hypertension and diabetes, when part of guideline-directed therapy.
Cough is uncommon with ARBs and occurs far less often than with ACE inhibitors. If you had ACE inhibitor cough, olmesartan is a common alternative.
Use with caution in kidney disease and monitor closely; in severe renal impairment, the maximum recommended dose is often 20 mg daily. No routine dose change is needed for mild-to-moderate hepatic impairment, but start low and monitor.
Human data are limited; ARBs are generally not preferred for breastfeeding, especially with newborns. Discuss safer alternatives with your clinician.
Yes, for ages 6–16. Typical starting doses are 10 mg daily if under 35 kg (up to 20 mg) and 20 mg daily if 35 kg or more (up to 40 mg), as directed by a pediatric specialist.
Generic olmesartan is widely available; the original brand was Benicar. Combination products include olmesartan/hydrochlorothiazide (Benicar HCT), olmesartan/amlodipine (Azor), and olmesartan/amlodipine/HCTZ (Tribenzor).
Do not stop abruptly without guidance; blood pressure usually rebounds. Your clinician may taper or switch therapy if indicated and will track readings to prevent spikes.
Both are ARBs that lower blood pressure effectively; olmesartan often provides stronger 24-hour BP reduction at equivalent doses, while losartan may require twice-daily dosing in some patients. Losartan uniquely lowers uric acid, helpful in gout; both are inexpensive generics.
Both control hypertension well. Valsartan has additional FDA indications for heart failure and post–heart attack care; olmesartan does not but is potent for BP lowering. Choice depends on comorbidities, dosing needs, and tolerance.
Telmisartan has a longer half-life (~24 hours) and often excellent trough control; olmesartan’s half-life is ~13 hours and also provides reliable once-daily coverage. Telmisartan has robust outcomes data (e.g., ONTARGET); selection is individualized.
Both are effective ARBs; candesartan also treats heart failure with reduced ejection fraction. For pure hypertension, efficacy and side effects are similar; dosing and comorbidity profiles guide the choice.
Irbesartan carries an indication for diabetic nephropathy; olmesartan reduces BP and can help protect kidneys as part of class effects but lacks that specific label. Both are suitable in diabetes; monitor potassium and kidney function with either.
Head-to-head data suggest azilsartan can be very potent for BP reduction at approved doses. Olmesartan is also strong and widely used; cost and availability often favor olmesartan, while azilsartan may be pricier.
Both are ARBs with similar class side effects; olmesartan is more commonly used and studied in fixed-dose combinations. Eprosartan is less frequently prescribed; either can be effective if tolerated and dosed appropriately.
Side effects are broadly similar: dizziness, hyperkalemia, and kidney function changes. A unique consideration is olmesartan’s rare sprue-like enteropathy (chronic diarrhea/weight loss), not clearly seen with other ARBs.
Telmisartan, olmesartan, azilsartan, and candesartan typically provide strong 24-hour coverage. Individual response varies; ambulatory BP monitoring or home logs can help tailor the choice.
Both lower blood pressure and protect kidneys/heart; ACE inhibitors have more cough and angioedema. If you developed ACE-inhibitor cough or angioedema, an ARB like olmesartan is often preferred; monitor potassium and kidney function with either.
For similar BP lowering, common high-dose comparisons are: olmesartan 40 mg ≈ losartan 100 mg ≈ valsartan 160–320 mg ≈ irbesartan 300 mg ≈ candesartan 32 mg ≈ telmisartan 80 mg ≈ azilsartan 80 mg ≈ eprosartan 600–800 mg. These are general guides; clinical response drives dosing.
Some (telmisartan, valsartan, candesartan, losartan) have large outcomes trials or additional indications (heart failure, post-MI, stroke reduction). Olmesartan has strong BP-lowering data; outcome differences are usually modest and patient-specific factors dominate.
Yes. Olmesartan, losartan, valsartan, telmisartan, irbesartan, and candesartan are available as low-cost generics; azilsartan may be more expensive. Insurance formularies and fixed-dose combination availability often influence selection.
