Olmesartan Risks, Warnings, and Complications

HARM TO AN UNBORN BABY: Olmesartan can be harmful to an unborn baby if a pregnant woman takes this medicine, especially in the second or third trimester (the last 6 months of the pregnancy). Olmesartan and other drugs that act on the renin angiotensin system reduce renal perfusion and fetal renal function, resulting in oligohydramnios (low levels of amniotic fluid), underdevelopment of the baby’s lungs, skeletal deformities, and an increased risk of fetal and neonatal morbidity and death. Potential neonatal adverse effects can include underdevelopment of the skull (hypoplasia), little or no urination, low blood pressure, renal impairment, renal failure, and even death. Stop taking Benicar (olmesartan) immediately and call your doctor if you become pregnant while on this medicine. In addition, remember that olmesartan and other drugs that act on the renin angiotensin system are not suitable for children under 1 year of age as these medicines can have adverse effects on immature kidneys.

BLOOD PRESSURE REDUCTION: Benicar (olmesartan) can cause symptomatic hypotension (low blood pressure) in people who have an activated renin-angiotensin-aldosterone system. This includes people who are dehydrated or salt-depleted, for example, from high doses of diuretics or water pills. Your healthcare provider may start treatment at a lower dose and keep you under close medical supervision if this is the case. If you develop low blood pressure, you may need an intravenous infusion of normal saline to stabilize your blood pressure. A temporary hypotensive response does not mean you cannot take olmesartan in the future. You can probably continue on this blood pressure medicine once your blood pressure has stabilized.

WORSENING KIDNEY FUNCTION: Due to their inhibitory effect on the renin-angiotensin-aldosterone system, Benicar (olmesartan) and other angiotensin receptor antagonists can cause impaired renal function, resulting in oliguria (little or no urine) and/or progressive azotemia (excessive nitrogen, creatinine, and other waste products in the blood). Rarely, it can lead to acute renal failure and even death. The risk of these complications is higher if you have certain medical conditions such as severe congestive heart failure or renal artery stenosis or take other medications that can also affect your kidneys. Your provider will monitor renal function periodically while you are on olmesartan. Keep all your laboratory and medical appointments during treatment. 

SEVERE DIARRHEA: People taking olmesartan are at risk of developing a sprue-like enteropathy (severe chronic diarrhea and significant weight loss). This can happen several months or even years after starting this medication. Call your doctor without delay if you develop severe diarrhea during treatment with olmesartan. Your doctor may change you over to other antihypertensive medications.

HIGH POTASSIUM LEVELS: Olmesartan and other drugs that act on the renin angiotensin system can cause hyperkalemia (high potassium levels). The risk is higher in people with diabetes mellitus, renal insufficiency, and those taking potassium-sparing diuretics. Your healthcare provider will monitor serum potassium levels while you are on olmesartan. Do not take potassium supplements or potassium-containing salt substitutes while you are on olmesartan without talking to your doctor first.