Olmesartan is used to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Olmesartan belongs to a class of drugs called angiotensin receptor blockers (ARBs). It works by relaxing blood vessels so that blood can flow more easily.
Take this medication by mouth as directed by your doctor, usually once daily with or without food. The dosage is based on your medical condition and response to treatment. If you are using the liquid form of this medication, shake the bottle well before each dose. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. If you also take certain drugs to lower your cholesterol (bile acid-binding resins such as cholestyramine, colesevelam, colestipol), take olmesartan at least 4 hours before any of these medications. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick. Tell your doctor if your condition does not improve or if it worsens (for example, your blood pressure readings increase).
Dizziness or lightheadedness may occur as your body adjusts to the medication. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: fainting, symptoms of a high potassium blood level (such as muscle weakness, slow/irregular heartbeat), signs of kidney problems (such as change in the amount of urine), severe/persistent diarrhea. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Store tablets at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets. Store the suspension in the refrigerator at 36-46 degrees F (2-8 degrees C). Do not freeze. Discard any unused suspension after 4 weeks. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
See also How to Use and Precautions sections. Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: aliskiren, lithium, drugs that may increase the level of potassium in the blood (such as ACE inhibitors including benazepril/lisinopril, birth control pills containing drospirenone). Some products have ingredients that could raise your blood pressure or worsen your heart failure. Tell your pharmacist what products you are using, and ask how to use them safely (especially cough-and-cold products, diet aids, or NSAIDs such as ibuprofen/naproxen).
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe dizziness, fainting.