From the Guidelines
Losartan can cause several side effects, including dizziness, lightheadedness, fatigue, and upper respiratory infections, as well as more serious side effects like allergic reactions, kidney problems, and angioedema, as reported in various studies 1.
Common Side Effects
- Dizziness and lightheadedness
- Fatigue
- Upper respiratory infections like cough or cold symptoms
- Low blood pressure, especially when starting the medication or increasing the dose
Serious Side Effects
- Allergic reactions (rash, itching, swelling)
- Kidney problems
- Angioedema (severe swelling of face, lips, tongue, or throat)
- Muscle pain, weakness, or liver problems in some individuals These side effects occur because losartan blocks angiotensin II receptors, affecting blood vessel tone, kidney function, and electrolyte balance, as explained in the studies 1.
Monitoring and Precautions
Regular monitoring of blood pressure, kidney function, and potassium levels is important while taking losartan, especially during the initial treatment period, to minimize the risk of adverse reactions, as suggested by the guidelines 1. If experiencing severe side effects like difficulty breathing, chest pain, or signs of allergic reaction, patients should seek immediate medical attention. It is also important to note that the combination of an ACEI and ARBs may produce more reduction of LV size than either agent alone, but may also result in more side effects, as reported in the studies 1.
From the FDA Drug Label
What are the possible side effects of Losartan Potassium Tablets? Losartan Potassium Tablets may cause the following side effects that may be serious: • Injury or death of unborn babies. • Allergic reaction. Symptoms of an allergic reaction are swelling of the face, lips, throat or tongue. • Low blood pressure (hypotension). Low blood pressure may cause you to feel faint or dizzy. • For people who already have kidney problems, you may see a worsening in how well your kidneys work. • High blood levels of potassium The most common side effects of Losartan Potassium Tablets in people with high blood pressure are: • “colds” (upper respiratory infection) • dizziness • stuffy nose • back pain The most common side effects of Losartan Potassium Tablets in people with type 2 diabetes with diabetic kidney disease are: • diarrhea • tiredness • low blood sugar • chest pain • high blood potassium • low blood pressure
The side effects of Losartan (Angiotensin II receptor antagonist) include:
- Serious side effects:
- Injury or death of unborn babies
- Allergic reaction
- Low blood pressure (hypotension)
- Worsening of kidney problems
- High blood levels of potassium
- Common side effects in people with high blood pressure:
- Upper respiratory infection
- Dizziness
- Stuffy nose
- Back pain
- Common side effects in people with type 2 diabetes with diabetic kidney disease:
- Diarrhea
- Tiredness
- Low blood sugar
- Chest pain
- High blood potassium
- Low blood pressure 2
From the Research
Side Effects of Losartan
The side effects of Losartan, an angiotensin II receptor antagonist, have been studied in various clinical trials. Some of the common side effects reported include:
- Headache 3, 4, 5
- Dizziness 3, 4, 6
- Upper respiratory tract infection 4
- Asthenia/fatigue 4
- Nausea and vomiting 5
- Anemia 5
- Lower-extremity edema (more common in patients taking amlodipine) 6
Less Common Side Effects
Some less common side effects of Losartan have also been reported, including:
- Cough (occurs in approximately 3.1% of patients) 4
- Angioedema/anaphylactoid reactions (a well-documented detrimental side effect) 5
- Tremors and dysarthria (reported in a case study) 5
Tolerability Profile
Losartan has been shown to have a favorable tolerability profile, with a similar incidence of cough to placebo in patients with a history of ACE inhibitor-related cough 3. The drug is also associated with a low incidence of clinically relevant adverse metabolic effects or laboratory abnormalities 3. Additionally, losartan has been found to be well tolerated in patients with concomitant illnesses, such as diabetes mellitus, renal impairment, or heart failure 4.