Learn about the potential side effects of Benicar (olmesartan). Includes common and rare side effects information for consumers and healthcare professionals. The Benicar is amazing in the relief I get from the muscle pain and fatigue. The first pill I took had almost complete relief within minutes after taking it. Unfortunately, after being on the 3 times a day 40mg for three weeks, I decided to stop the For High Blood Pressure: Benicar kept my HBP down to normal for years. Aside from fatigue and subsequent weight gain I felt no ill effects as long as I took it at bedtime. Summary. Fatigue is found among people who take Benicar hct, especially for people who are female, 60+ old , have been taking the drug for 2 - 5 years, also take medication Benicar, and have High blood cholesterol. After trying several other BP medications, I have been on Benicar for a year. I initially had dizziness. Over the past 4 months, I have developed horrible muscle fatigue, tingling and numbness in my arms and sometimes my legs & feet, blurred vision and terrible shortness of breath. I was diagnosed with crohns disease many years ago, then three years ago Sarcoid, ankylosing spondilitis, poly arthritis, chronic fatigue and Fibromyalgia. Summary. Fatigue is found among people who take Benicar, especially for people who are female, 60+ old , have been taking the drug for 1 month, also take medication Aspirin, and have High blood cholesterol. Benicar. Benicar-related intestinal problems can cause symptoms such as chronic diarrhea, abdominal pain, nausea, dehydration, and fatigue. Many patients experiencing these side effects require hospitalization. Benicar is the brand name for the generic medication, olmesartan medoxomil. It is an antihypertensive drug used to treat high blood pressure which may also help to reduce the chance for heart attack, stroke, and kidney disease. (BP was 160/100 and now averages 125/75) for 18 months with good results except for fatigue, some diziness and slow pulse (50) My Dr, switched me to Benicar 20mg last week and now my heart races at 120+ and my anxiety level is through the roof.