Reviewed on 1/26/2022

What Is Olmesartan and How Does It Work?

Olmesartan is a prescription medication used for the treatment of hypertension

  • Olmesartan is available under the following different brand names: Benicar

What Are Dosages of Olmesartan?

Adult and pediatric dosage


  • 5mg
  • 20mg
  • 40mg


Adult dosage

  • 20 mg/day orally initially; may be increased to 40 mg/day orally after 2 weeks; a diuretic may be added

Pediatric dosage

  • Children younger than 6 years of age: Safety and efficacy not established

Children 6-16 years of age: 

  • Weighing less than 20 kg: Safety and efficacy not established
  • Weighing 20-35 kg: 10 mg/day orally initially; after 2 weeks, maybe increased if the response is inadequate; dosage range: 10-20 mg/day
  • Weighing more than 35 kg: 20 mg/day orally initially; after 2 weeks, maybe increased if the response is inadequate; dosage range: 20-40 mg/day; not to exceed 40 mg/day

Dosage Considerations – Should be Given as Follows

  • See “Dosages”

What Are Side Effects Associated with Using Olmesartan?

Common side effects of olmesartan include:

Serious side effects of olmesartan include:

Rare side effects of olmesartan include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What other drugs interact with Olmesartan?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

  • Olmesartan has severe interaction with the following drug:
    • aliskiren
  • Olmesartan has serious interactions with at least 13 other drugs.
  • Olmesartan has moderate interactions with at least 126 other drugs
  • Olmesartan has minor interaction with the following drugs:

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What are warnings and precautions for Olmesartan?


  • Hypersensitivity
  • Do not coadminister with aliskiren in patients with diabetes mellitus or with renal impairment (i.e., GFR less than 60 mL/min/1.73 m²)

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Olmesartan?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Olmesartan?”


  • Use caution in congestive heart failure (CHF), surgery or anesthesia, volume depletion (consider lower dosage)
  • Angioedema reported; may occur at any time during treatment, especially after the first dose; risk increases in patients with idiopathic or hereditary angioedema or experiencing angioedema following ACE-inhibitor therapy; prolonged monitoring of air pathways may be necessary as reactions are associated with airway obstruction; not for administration to patients with prior history of angioedema following therapy with ARBs; discontinue therapy immediately if angioedema occurs; intramuscular administration of epinephrine may be necessary to manage angioedema
  • Coadministration with mTOR inhibitors (e.g., temsirolimus) may increase the risk for angioedema
  • Risk of hypotension, especially in patients with volume or salt depletion secondary to salt restriction or prolonged diuretic treatment; initiate treatment in such patients under close medical supervision and consider starting at a lower dose
  • Risk of hyperkalemia; monitor serum electrolytes periodically; use with caution, if at all, and monitor potassium closely in patients with risk factors, including diabetes mellitus, renal dysfunction, potassium supplements, and/or potassium-containing salts
  • Use with caution in patients with unstented unilateral/bilateral renal artery stenosis; avoid therapy when unstented bilateral renal artery stenosis is present due to elevated risk of deterioration in renal function unless possible benefits outweigh risks
  • Renal impairment reported; may occur in patients with low renal blood flow (e.g., heart failure, renal artery stenosis), whose glomerular filtration rate is dependent on efferent arteriolar vasoconstriction by angiotensin II, which may result in acute renal failure, oliguria, and progressive azotemia; discontinue therapy only in patients with progressive and/or significant deterioration in renal function
  • Use caution in patients with pre-existing renal insufficiency
  • Avoid use in patients with ascites resulting from cirrhosis or refractory ascites; monitor blood pressure and renal function closely if use cannot be avoided
  • Intestinal problems (i.e., sprue-like enteropathy) reported; symptoms may include severe, chronic diarrhea with substantial weight loss; discontinue treatment and consider other antihypertensive therapy
  • Dual blockade of the renin-angiotensin system with angiotensin-receptor blockers (ARBs), angiotensin-converting enzyme (ACE) inhibitors, or aliskiren is associated with increased risk of hypotension, hyperkalemia, and altered renal function (including acute renal failure) in comparison with monotherapy; closely monitor blood pressure
  • Children younger than 1 year of age must not receive olmesartan for hypertension; drugs that act directly on the renin-angiotensin-aldosterone system can have adverse effects on the development of immature kidneys

Pregnancy and Lactation

  • Can cause fetal harm when administered to a pregnant woman; use of drugs that act on the renin-angiotensin system during second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death
  • Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents
  • Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section and post-partum hemorrhage)
  • Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death
  • Pregnant women with hypertension should be carefully monitored and managed accordingly

There is no information regarding the presence of drugs in human milk, effects on the breastfed infant, or on milk production; the drug is secreted at low concentration in the milk of lactating rats; because of potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, considering the importance of the drug to mother.

From WebMD Logo

Heart Health Resources
Health Solutions From Our Sponsors

Health Solutions From Our Sponsors