Benicar is used to treat high blood pressure (hypertension). Learn about side effects, interactions and indications. Olmesartan (Benicar) is an oral medication used to treat high blood pressure. Learn about side effects, warnings, dosage, and more. Fast Facts ACEIs and ARBs are two of the many kinds of blood pressure pills. Both kinds of pills (ACEIs and ARBs) do a good job of lowering blood pressure. Celecoxib is used to relieve pain, tenderness, swelling and stiffness caused by osteoarthritis (arthritis caused by a breakdown of the lining of the joints), rheumatoid arthritis (arthritis caused by swelling of the lining of the joints), and ankylosing spondylitis (arthritis that mainly affects the spine). Learn about the potential side effects of Benicar (olmesartan). Includes common and rare side effects information for consumers and healthcare professionals. What should I discuss with my healthcare provider before taking olmesartan (Benicar)? You should not take olmesartan if you are allergic to it. Nabumetone is used to relieve pain, tenderness, swelling, and stiffness caused by osteoarthritis (arthritis caused by a breakdown of the lining of the joints) and rheumatoid arthritis (arthritis caused by swelling of the lining of the joints). How to use Benicar. 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. High Blood Pressure Medicines. Use this guide to help you talk to your doctor about your blood pressure medicines. Ask your doctor about the risks of taking your medicine. Benicar (olmesartan medoxomil) is an angiotensin II receptor antagonist used to reduce and control hypertension (high blood pressure). Generic Benicar is available outside of the U.S. Common side effects of Benicar include.