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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Thiazide Diuretic [EPC]
Olmesartan medoxomil is a potent, long-acting angiotensin II receptor blocker (ARB) primarily used to manage hypertension. It works by inhibiting the vasoconstrictive effects of angiotensin II to lower blood pressure and reduce cardiovascular risk.
Name
Olmesartan Medoxomil
Raw Name
OLMESARTAN MEDOXOMIL
Category
Thiazide Diuretic [EPC]
Drug Count
15
Variant Count
274
Last Verified
February 17, 2026
RxCUI
403853, 403854, 403855, 847042, 847055, 847060, 730861, 730866, 730869, 730872, 744624, 744628, 744632, 744636, 349373, 349401, 349405, 999967, 999986, 999991, 999996, 1000001, 352199, 352200, 352201, 999971, 999990, 999995, 1000000, 1000005
UNII
0J48LPH2TH, 6M97XTV3HD, 864V2Q084H
About Olmesartan Medoxomil
Olmesartan medoxomil is a potent, long-acting angiotensin II receptor blocker (ARB) primarily used to manage hypertension. It works by inhibiting the vasoconstrictive effects of angiotensin II to lower blood pressure and reduce cardiovascular risk.
Detailed information about Olmesartan Medoxomil
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Olmesartan Medoxomil.
Olmesartan medoxomil is a highly selective, non-peptide angiotensin II receptor antagonist (more commonly known as an ARB) that is utilized primarily in the management of hypertension (high blood pressure). According to the FDA-approved labeling originally granted in 2002 under the brand name Benicar, this agent is a prodrug that is rapidly converted to its active metabolite, olmesartan, during absorption from the gastrointestinal tract. It belongs to a pharmacological class of drugs that target the renin-angiotensin-aldosterone system (RAAS), which is the primary hormonal mechanism the body uses to regulate blood pressure and fluid balance. By specifically blocking the binding of angiotensin II to the AT1 receptor found in many tissues—most notably vascular smooth muscle and the adrenal gland—olmesartan inhibits the vasoconstricting and aldosterone-secreting effects of this hormone.
In the context of modern cardiology, olmesartan medoxomil is regarded for its potency and long duration of action, often providing 24-hour blood pressure control with a single daily dose. Lowering blood pressure is critical because chronic hypertension significantly increases the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions (heart attacks). Clinical trials, such as those reviewed by the American Heart Association (AHA) and the American College of Cardiology (ACC), have consistently demonstrated that olmesartan is effective as both a monotherapy and as part of combination regimens with other antihypertensive agents, such as thiazide diuretics or calcium channel blockers.
To understand how olmesartan medoxomil works, one must first understand the role of angiotensin II. Angiotensin II is a powerful vasoconstrictor (a substance that narrows blood vessels) and is the primary vasoactive hormone of the RAAS. It acts by binding to specific receptors: the AT1 receptor and the AT2 receptor. While the AT2 receptor's role is less clearly defined in blood pressure regulation, the AT1 receptor is responsible for the harmful effects of hypertension, including systemic vasoconstriction, the release of aldosterone (which causes the body to retain salt and water), and the stimulation of the sympathetic nervous system.
Olmesartan medoxomil acts as a competitive antagonist at the AT1 receptor site. Unlike ACE inhibitors, which prevent the formation of angiotensin II, ARBs like olmesartan block the hormone's action regardless of its source or route of synthesis. This is a crucial distinction because angiotensin II can be produced through non-ACE pathways (such as the chymase pathway). By blocking the AT1 receptor, olmesartan prevents the narrowing of the arteries, allowing them to dilate (relax). This relaxation reduces the resistance against which the heart must pump, thereby lowering systemic blood pressure. Furthermore, by inhibiting aldosterone release, olmesartan helps the kidneys excrete excess sodium and water, further reducing the volume of fluid in the circulatory system.
Olmesartan medoxomil is FDA-approved for the treatment of hypertension in adults and children aged 6 to 16 years. It may be used alone or in combination with other antihypertensive agents. While its primary indication is hypertension, healthcare providers may occasionally use it off-label for other conditions related to the RAAS, such as diabetic nephropathy (kidney disease in diabetic patients) or heart failure, although other ARBs like losartan or valsartan may have more robust clinical trial data for those specific secondary indications. The goal of therapy is to reach blood pressure targets established by clinical guidelines (e.g., <130/80 mmHg) to prevent long-term organ damage.
Olmesartan medoxomil is available in several oral tablet strengths to allow for precise titration:
It is also frequently found in fixed-dose combination tablets with hydrochlorothiazide (a diuretic) or amlodipine (a calcium channel blocker) to simplify dosing for patients requiring multiple medications to control their blood pressure.
> Important: Only your healthcare provider can determine if Olmesartan Medoxomil is right for your specific condition. Regular monitoring of blood pressure and kidney function is essential during treatment.
For the treatment of hypertension in adults, the standard starting dose of olmesartan medoxomil is 20 mg taken orally once daily. If blood pressure remains inadequately controlled after two weeks of therapy, your healthcare provider may increase the dose to 40 mg once daily. Clinical data suggests that doses above 40 mg do not provide significantly greater blood pressure lowering effects, and twice-daily dosing does not offer an advantage over once-daily dosing. For patients who are volume-depleted (e.g., those on high-dose diuretics), a lower starting dose may be considered to avoid sudden hypotension (excessively low blood pressure).
Olmesartan medoxomil is approved for use in children aged 6 to 16 years. The dosing is typically based on the child's weight:
For children who cannot swallow tablets, a pharmacist may be able to prepare an oral suspension using olmesartan tablets. Use in children under the age of 1 year is strictly contraindicated due to the risk of affecting kidney development.
No initial dosage adjustment is typically required for patients with mild to moderate renal impairment (creatinine clearance >20 mL/min). However, in patients with severe renal impairment (CrCl <20 mL/min), or those on dialysis, clinical monitoring is required, and the lowest effective dose should be used. The drug is not removed by hemodialysis.
No initial dosage adjustment is necessary for patients with mild to moderate hepatic (liver) impairment. Olmesartan has not been extensively studied in patients with severe hepatic impairment, so it should be used with caution in this population.
In general, no initial dosage adjustment is required for elderly patients (65 years and older). However, because older adults are more likely to have decreased renal or hepatic function and may be taking other medications, healthcare providers usually monitor these patients more closely during the initiation and titration phases.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular schedule. Do not take two doses at once to make up for a missed one, as this increases the risk of side effects like dizziness or fainting.
Symptoms of an olmesartan overdose primarily include severe hypotension (low blood pressure) and tachycardia (rapid heart rate). Bradycardia (slow heart rate) could also occur if parasympathetic stimulation is triggered. If an overdose is suspected, seek emergency medical attention immediately. Treatment is generally supportive and may involve intravenous fluids to increase blood pressure.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, as stopping blood pressure medication abruptly can cause a dangerous spike in blood pressure.
While olmesartan medoxomil is generally well-tolerated, some patients may experience side effects. The most common side effect reported in clinical trials is dizziness, which occurs in about 3% of patients. This is often a result of the body adjusting to lower blood pressure levels. Other common symptoms include:
These side effects occur in a smaller percentage of the population but are still documented in clinical literature:
> Warning: Stop taking Olmesartan Medoxomil and call your doctor immediately if you experience any of these serious symptoms.
With prolonged use, the primary concern is the impact on renal (kidney) function. In patients whose renal function depends on the activity of the RAAS (such as those with renal artery stenosis), long-term use of ARBs can lead to acute renal failure. Periodic blood tests to monitor serum creatinine and potassium levels are necessary for long-term safety.
Fetal Toxicity: Olmesartan medoxomil carries a Boxed Warning regarding its use during pregnancy. When pregnancy is detected, olmesartan should be discontinued as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and even death to the developing fetus, particularly during the second and third trimesters. Potential risks include oligohydramnios (reduced amniotic fluid), which can lead to fetal lung hypoplasia and skeletal deformations, as well as neonatal hypotension and renal failure.
Report any unusual symptoms to your healthcare provider. Your doctor can help determine if a side effect is related to the medication or another underlying condition.
Olmesartan medoxomil is a potent medication that requires careful medical supervision. It is not suitable for everyone, and certain precautions must be taken to ensure patient safety. Patients should be aware that the blood pressure-lowering effects may take several weeks to reach their peak. It is also vital to stay hydrated, as excessive sweating, vomiting, or diarrhea can lead to a significant drop in blood pressure (hypotension).
Healthcare providers will typically order the following tests while you are taking olmesartan:
Olmesartan medoxomil generally does not affect the ability to drive or operate machinery. However, because it can cause dizziness or fatigue (especially when starting the drug or increasing the dose), you should see how you react to the medication before performing tasks that require alertness.
Alcohol can enhance the blood pressure-lowering effect of olmesartan, which may increase the risk of dizziness, fainting, or lightheadedness. It is generally advised to limit alcohol consumption while taking antihypertensive medications.
Do not stop taking olmesartan medoxomil without consulting your doctor. Abruptly stopping the medication can cause "rebound hypertension," where blood pressure rises quickly to levels higher than before treatment, increasing the risk of cardiovascular events.
> Important: Discuss all your medical conditions, especially kidney disease, liver disease, or heart problems, with your healthcare provider before starting Olmesartan Medoxomil.
Olmesartan is not known to interfere significantly with common laboratory tests, though it will naturally affect blood pressure readings and may cause slight elevations in serum creatinine or potassium, which are pharmacological effects rather than analytical interference.
For each major interaction, the primary mechanism is often pharmacodynamic (overlapping effects on the kidneys or electrolytes) rather than pharmacokinetic (CYP enzyme competition). Management usually involves dose adjustment, frequent lab monitoring, or choosing alternative therapies.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter pain relievers like ibuprofen or naproxen.
Olmesartan medoxomil must NEVER be used in the following circumstances:
Conditions requiring careful risk-benefit analysis and intensive monitoring include:
While olmesartan is chemically distinct from ACE inhibitors, patients who have had severe reactions to other ARBs (like valsartan or candesartan) should use olmesartan with extreme caution, as cross-sensitivity within the ARB class is possible.
> Important: Your healthcare provider will evaluate your complete medical history, including any history of kidney disease or previous drug allergies, before prescribing Olmesartan Medoxomil.
FDA Pregnancy Category D (Evidence of Risk). Olmesartan medoxomil is contraindicated in pregnancy. Use of drugs that act on the RAAS during the second and third trimesters reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. If pregnancy is detected, discontinue olmesartan immediately. If a patient becomes pregnant while on this medication, they should be informed of the potential hazard to the fetus.
It is not known whether olmesartan is excreted in human breast milk, although it is secreted in the milk of lactating rats. Because of the potential for adverse effects on the nursing infant (particularly on kidney development), a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. Most clinicians recommend alternative antihypertensive agents with better safety data during breastfeeding, such as methyldopa or certain beta-blockers.
Olmesartan is approved for children 6 years and older for the treatment of hypertension. It has been shown to be effective and generally well-tolerated in this age group. However, it must not be used in children younger than 1 year of age because it may interfere with normal kidney development. Long-term effects on growth and development in children have not been extensively studied, but no specific concerns have been raised in clinical practice.
Clinical studies did not identify overall differences in effectiveness or safety between patients over 65 and younger patients. However, elderly patients are more likely to have decreased renal function and are often taking multiple medications (polypharmacy), which increases the risk of drug interactions and side effects like dizziness. Caution is advised when increasing the dose in elderly patients to avoid falls related to orthostatic hypotension.
In patients with renal impairment, serum creatinine and potassium levels should be monitored periodically. In patients with severe renal impairment (CrCl <20 mL/min), olmesartan should be used with caution. There is no need for dose adjustment in mild to moderate impairment, but the risk of hyperkalemia increases as kidney function declines.
No dose adjustment is required for mild-to-moderate hepatic impairment. However, since olmesartan is partially eliminated via the bile, severe hepatic impairment could theoretically increase drug levels. Use in severe hepatic impairment has not been studied.
> Important: Special populations require individualized medical assessment. Always inform your doctor if you are planning to become pregnant or are currently breastfeeding.
Olmesartan medoxomil is a prodrug that is hydrolyzed to olmesartan during absorption. Olmesartan is a selective angiotensin II receptor antagonist. It works by blocking the binding of angiotensin II to the AT1 receptor in vascular smooth muscle and the adrenal gland. Angiotensin II is the primary vasoactive hormone of the renin-angiotensin-aldosterone system (RAAS) and a powerful vasoconstrictor. By blocking the AT1 receptor, olmesartan inhibits the vasoconstrictor and aldosterone-secreting effects of angiotensin II. It does not inhibit ACE (kininase II), the enzyme that converts angiotensin I to angiotensin II and degrades bradykinin. Therefore, it does not result in the accumulation of bradykinin, which is the mechanism thought to cause the persistent dry cough often associated with ACE inhibitors.
Olmesartan produces a dose-dependent inhibition of the pressor effect of angiotensin II infusions. The onset of antihypertensive action is generally observed within 1 to 2 weeks, with the full effect occurring by 4 weeks. A single daily dose provides effective blood pressure lowering for 24 hours. There is no evidence of a "first-dose" phenomenon (a massive drop in blood pressure after the very first dose) in most patients, and stopping the drug does not lead to rapid rebound hypertension.
| Parameter | Value |
|---|---|
| Bioavailability | ~26% |
| Protein Binding | 99% (primarily albumin) |
| Half-life | ~13 hours |
| Tmax | 1 to 2 hours |
| Metabolism | Not metabolized by CYP450; Prodrug hydrolysis only |
| Excretion | Renal 35-50%, Fecal 50-65% |
Olmesartan medoxomil is a member of the Angiotensin II Receptor Blocker (ARB) class. Other medications in this class include losartan (Cozaar), valsartan (Diovan), and candesartan (Atacand). It is distinct from ACE inhibitors and direct renin inhibitors, though all three classes target the RAAS pathway.
Medications containing this ingredient
Common questions about Olmesartan Medoxomil
Olmesartan medoxomil is primarily used to treat hypertension, also known as high blood pressure, in adults and children aged 6 to 16 years. By lowering blood pressure, the medication helps prevent serious cardiovascular events such as strokes and heart attacks. It belongs to a class of drugs called angiotensin II receptor blockers (ARBs), which work by relaxing blood vessels so blood can flow more easily. While it is mainly used for blood pressure, healthcare providers may occasionally use it off-label for other conditions related to heart or kidney health. It is often prescribed when other blood pressure medications are not well-tolerated or are insufficient on their own.
The most common side effect of olmesartan medoxomil is dizziness, which affects about 3% of patients as their bodies adjust to lower blood pressure. Other frequently reported side effects include headaches, upper respiratory tract infections (like the common cold), and back pain. Some patients may also experience a general sense of fatigue or nausea. A very specific but rare side effect to watch for is sprue-like enteropathy, which causes severe, chronic diarrhea and weight loss. Most common side effects are mild and temporary, but any persistent or worsening symptoms should be discussed with a healthcare provider.
It is generally recommended to limit or avoid alcohol while taking olmesartan medoxomil. Alcohol can have an additive effect with the medication, causing your blood pressure to drop lower than intended. This can lead to increased side effects such as severe dizziness, lightheadedness, and even fainting, especially when standing up from a sitting or lying position. Chronic alcohol use can also interfere with overall blood pressure management and may worsen other underlying health conditions. If you choose to drink, do so in moderation and only after discussing it with your doctor to ensure it is safe for your specific situation.
No, olmesartan medoxomil is not safe during pregnancy and carries a Boxed Warning from the FDA. Using this medication during the second and third trimesters can cause severe injury or even death to the developing fetus by interfering with its kidney development. If you are planning to become pregnant or discover that you are pregnant while taking olmesartan, you must contact your healthcare provider immediately to switch to a safer alternative. It is considered a Pregnancy Category D drug, meaning there is clear evidence of human fetal risk. Women of childbearing age should discuss effective birth control options with their doctor while on this medication.
While olmesartan medoxomil begins to work within hours of the first dose, its full blood pressure-lowering effects are typically not seen immediately. Most patients will notice a significant reduction in their blood pressure readings within 1 to 2 weeks of consistent daily use. However, it can take up to 4 weeks of treatment to reach the maximum effectiveness of a specific dose. Your doctor will likely wait at least two weeks before deciding whether to increase your dosage. It is important to continue taking the medication every day, even if you do not feel any different, as hypertension often has no outward symptoms.
You should never stop taking olmesartan medoxomil suddenly without first consulting your healthcare provider. Abruptly discontinuing blood pressure medication can cause your blood pressure to spike rapidly, a condition known as rebound hypertension. This sudden increase can put you at a higher risk for a heart attack or stroke. If you need to stop the medication due to side effects or for a medical procedure, your doctor will provide a plan to gradually taper your dose. Consistent use is key to long-term cardiovascular protection, so always keep a sufficient supply of your prescription.
If you miss a dose of olmesartan medoxomil, take it as soon as you remember that day. However, if it is already close to the time for your next scheduled dose, you should skip the missed dose and simply take your next one at the regular time. Never take two doses at once to make up for a missed one, as this significantly increases the risk of your blood pressure dropping too low, which can cause fainting. To help prevent missed doses, try taking your medication at the same time every day, such as with breakfast. If you find yourself frequently forgetting doses, consider using a pill organizer or a smartphone reminder app.
Weight gain is not a typical or common side effect of olmesartan medoxomil. In clinical trials, patients taking olmesartan did not show a significant trend toward gaining weight compared to those taking a placebo. In fact, one of the serious but rare side effects of the drug, sprue-like enteropathy, is actually associated with significant and unexplained weight loss. If you notice rapid weight gain while taking this medication, it is more likely to be caused by fluid retention, which could indicate a change in your heart or kidney function. You should report any sudden or unusual changes in your weight to your doctor immediately.
Olmesartan medoxomil can often be taken with other medications, and it is frequently combined with diuretics or calcium channel blockers for better blood pressure control. However, it can have serious interactions with certain drugs, such as lithium, NSAIDs (like ibuprofen), and potassium supplements. Taking it with other drugs that affect the renin-angiotensin system, like ACE inhibitors or aliskiren, is generally avoided due to the risk of kidney damage. Always provide your healthcare provider and pharmacist with a complete list of all prescription drugs, over-the-counter medicines, and herbal supplements you are using. This allows them to check for potential interactions that could make olmesartan less effective or more dangerous.
Yes, olmesartan medoxomil is available as a generic medication, which is typically much more affordable than the brand-name version, Benicar. Generic versions are required by the FDA to have the same active ingredient, strength, dosage form, and route of administration as the brand-name drug. They must also prove bioequivalence, meaning they work in the body the same way and provide the same clinical benefits. Most insurance plans cover the generic version of olmesartan. If you have been prescribed Benicar and wish to switch to the generic to save money, talk to your pharmacist or healthcare provider to ensure the transition is handled correctly.