Losartan vs. Hydrochlorothiazide for Hypertension: Important Differences and Potential Risks.

Key takeaways

Losartan (Cozaar) and hydrochlorothiazide (Microzide) are both used to treat high blood pressure, but they work in different ways. Losartan is an angiotensin II receptor blocker (ARB) that helps relax blood vessels and reduce water and salt retention, while hydrochlorothiazide is a diuretic (water pill) that makes you urinate more to remove extra fluid and certain electrolytes from your body. Losartan is typically taken once daily and can also help protect against stroke and slow down kidney problems in people with diabetes. Hydrochlorothiazide can be taken once or twice daily. Common side effects of losartan include dizziness and upper respiratory infections, whereas hydrochlorothiazide can cause dizziness, increased urination, and sensitivity to sunlight. Both medications are available in lower-cost generic forms.

Losartan

(Cozaar)

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Hydrochlorothiazide

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Summary for Losartan

Prescription only

Losartan, also known by the brand name Cozaar, is a first-choice medication that's used to lower blood pressure. It's also shown to protect against stroke in certain people. In addition, this medication can slow down the worsening of kidney problems in certain people with diabetes. Losartan (Cozaar) belongs to the drug class called angiotensin II receptor blockers (ARBs). This medication is taken by mouth once daily and is available as a lower-cost generic. Side effects can include dizziness, fatigue, and upper respiratory infections.

Indications for Losartan

High blood pressure
Lower the risk of stroke in people with high blood pressure who have a thickened heart (left ventricular hypertrophy)
Slow down the worsening of kidney problems in people with Type 2 diabetes and high blood pressure

Pros and Cons for Losartan

Pros

A first-choice blood pressure medication, including for those with heart failure, diabetes, and kidney problems
Taken once per day
Can be taken by children as young as 6 years old
Works similarly to angiotensin-converting enzyme (ACE) inhibitors, but with fewer side effects, like cough and swelling

Cons

Might cause dizziness
Might not work as well for Black people as other blood pressure medications do
Not safe to use during pregnancy
Can interact with medications like lithium and nonsteroidal anti-inflammatory drugs (NSAIDs)

Common Side Effects for Losartan

Upper respiratory infection (e.g., common cold; 8%)
Dizziness (3%)
Stuffy nose (2%)
Back pain (2%)

Warnings for Losartan

Harm to unborn baby
Low blood pressure
Kidney damage
High potassium levels

Summary for Hydrochlorothiazide

Prescription only

Hydrochlorothiazide is a diuretic or water pill. It helps lower blood pressure. It also helps with swelling from fluid buildup (edema) caused by some health conditions, like heart failure and kidney problems. People of all ages can take hydrochlorothiazide tablets and capsules. But children typically take much smaller, weight-based doses. You typically take your dose by mouth once (sometimes twice) daily, but avoid nighttime dosing so you won't wake up to urinate. Some common side effects are dizziness and urinating more often.

Indications for Hydrochlorothiazide

High blood pressure
Swelling in the body from fluid buildup (edema)

Pros and Cons for Hydrochlorothiazide

Pros

Helps getting rid of extra fluid in your body
A first-choice treatment option if you have high blood pressure or heart failure
Dose can be adjusted based on how well it's working for you

Cons

Can make you urinate more often
Can cause electrolytes and fluid levels to be out of balance, which can be dangerous
Might not be a good option for people with a sulfa allergy