Losartan, also known by its brand name Cozaar, is a medication frequently prescribed to manage high blood pressure. It is an angiotensin receptor blocker, or ARB, that works by relaxing and widening blood vessels. This action makes it easier for the heart to pump blood throughout the body. Losartan is also used to treat heart failure and to protect the kidneys in individuals with diabetic kidney disease.
The Most Common Losartan Side Effect
Dizziness is the most frequently reported side effect associated with losartan. This sensation of lightheadedness or feeling faint occurs because the medication lowers blood pressure, potentially leading to hypotension. This side effect is particularly common when first starting losartan or after a dose increase, and can be more pronounced if a person is also taking a diuretic, which further reduces fluid volume and blood pressure. Clinical studies indicate that dizziness affects approximately 3% to 14.1% of hypertensive patients.
Other Frequently Reported Side Effects
Beyond dizziness, several other side effects are commonly experienced by individuals taking losartan. Fatigue is reported as the body adjusts to the medication and lower blood pressure. Some individuals may also experience symptoms resembling a common cold, such as an upper respiratory infection or nasal congestion. Back pain is another common side effect, though its specific reason is not fully understood.
Headaches can also occur, particularly when treatment begins. These headaches are usually mild and resolve as the body adapts to the medication. Additionally, some patients may experience gastrointestinal issues like nausea, vomiting, or diarrhea. These effects are transient and improve over time.
Navigating Side Effects and Medical Consultation
Individuals experiencing mild dizziness while taking losartan can manage it by standing up slowly from a sitting or lying position. If dizziness occurs, lying down and then sitting for a few moments before standing again can help prevent fainting. Staying well-hydrated is also recommended. It is important to avoid driving or operating machinery if feeling dizzy.
Contacting a healthcare provider is important if dizziness worsens, becomes persistent, or is severe. Prompt medical attention is necessary for signs of a serious allergic reaction, such as sudden swelling of the face, lips, tongue, or throat, or difficulty breathing. Symptoms of high potassium levels (hyperkalemia) also require immediate consultation; these can include muscle weakness, an irregular heartbeat, or numbness and tingling. Never stop taking losartan without first consulting a healthcare professional.