Losartan is a medication commonly prescribed to manage cardiovascular conditions, such as high blood pressure and heart failure. Patients often wonder if it can cause heart palpitations, which can be unsettling.
Losartan’s Primary Role
Losartan belongs to a class of drugs known as angiotensin II receptor blockers (ARBs). These medications primarily function by relaxing blood vessels, which helps to lower blood pressure. The body produces a hormone called angiotensin II, which causes blood vessels to narrow and can lead to increased blood pressure. Losartan works by blocking the action of angiotensin II at its type 1 (AT1) receptors.
By inhibiting angiotensin II from binding to these receptors, losartan prevents the hormone’s constricting effect on blood vessels. This action leads to vasodilation, or the widening of blood vessels, allowing blood to flow more freely and reducing the workload on the heart. Losartan is prescribed for conditions such as high blood pressure, chronic kidney disease, and heart failure, and it can also help reduce the risk of stroke in patients with high blood pressure and an enlarged heart.
The Link Between Losartan and Palpitations
While losartan is generally well-tolerated, heart palpitations can occur as a side effect for a small percentage of individuals. Less than 1% of people taking losartan may experience palpitations, which can manifest as sensations of the heart fluttering, pounding, or skipping beats.
One mechanism involves losartan’s effect on electrolyte balance, particularly potassium levels. Losartan can increase potassium levels in the blood, a condition known as hyperkalemia. This occurs because the medication blocks the effects of angiotensin II, which normally stimulates the release of aldosterone, a hormone that promotes potassium excretion. When aldosterone’s action is reduced, the kidneys may retain more potassium. Elevated potassium levels can lead to symptoms like heart palpitations or irregular heartbeats.
Some individuals may also experience a reflexive increase in heart rate due to the vasodilation caused by losartan. When blood vessels widen and blood pressure drops, the body’s sympathetic nervous system might respond by increasing heart rate to maintain adequate blood flow, which could be perceived as palpitations. Losartan might also unmask or interact with pre-existing heart conditions that contribute to palpitations, making underlying arrhythmias more noticeable.
Recognizing and Responding to Palpitations
Heart palpitations can feel like a racing heart, a pounding sensation, or skipping beats. These sensations might be felt in the chest, throat, or neck and can occur at any time. While many instances of palpitations are harmless, it is important to be aware of warning signs.
Immediate medical attention is necessary if palpitations are accompanied by chest pain, pressure, or tightness; shortness of breath; dizziness or lightheadedness; unusual sweating; or fainting. These co-occurring symptoms could indicate a more serious underlying issue and warrant an emergency medical evaluation. If palpitations last for several minutes or longer, or are new or worsening, consulting a healthcare professional is advisable.
Patients should never stop or adjust their losartan dosage without first consulting their doctor. A healthcare provider can assess whether losartan is the cause, rule out other potential medical conditions, or determine if a medication adjustment is needed. Regular monitoring of electrolyte levels, particularly potassium, and kidney function is often recommended while taking losartan to detect and manage any potential imbalances that could contribute to heart rhythm changes.