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. Benicar is indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. Learn about Benicar (Olmesartan Medoxomil) may treat, uses, dosage, side effects, drug interactions, warnings, patient labeling, reviews, and related medications. Find patient medical information for Olmesartan Oral on WebMD including its uses, side effects and safety, interactions, pictures, warnings and user ratings.