Prescription medication · Thiazide Diuretic / ARB Combination

hydrochlorothiazide/losartan

Also sold as Hyzaar. Hyzaar is used to treat high blood pressure.

Data updated 2026-05-15

75,364
FDA reports
7
InteractionsFew interactions
$6.17
Brand price (NADAC)

What the data shows

hydrochlorothiazide/losartan (Hyzaar) is a prescription Thiazide Diuretic / ARB Combination, with 75,364 FDA adverse-event reports on file, with 7 documented drug interactions.

Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.

hydrochlorothiazide/losartan (Hyzaar) is a prescription Thiazide Diuretic / ARB Combination. Hyzaar is used to treat high blood pressure.

Hyzaar is a combination medicine that contains losartan and hydrochlorothiazide. It is used to lower high blood pressure.

Drug Pricing (NADAC)

Brand Price

$6.17/unit

Generic Available

No

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

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What it does

Hyzaar is used to treat high blood pressure.

Common side effects

Dizziness, Upper respiratory infection, Cough

Key warnings

If you are pregnant or plan to become pregnant, stop taking Hyzaar and tell your doctor right away.

The sections below are summarized in plain English from hydrochlorothiazide/losartan's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.

How It Works

Losartan blocks a substance in your body that tightens blood vessels. This helps blood vessels relax, which lowers blood pressure. Hydrochlorothiazide is a diuretic that helps your body get rid of extra salt and water, which also lowers blood pressure.

Side Effects (from patient reports)

Based on 75,364 FDA adverse event reports.

Most-reported reactions

Adverse reactions in FAERS for hydrochlorothiazide/losartan, by number of reports

reports

What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.

Source FDA Adverse Event Reporting System (FAERS)

Serious Warnings

If you are pregnant or plan to become pregnant, stop taking Hyzaar and tell your doctor right away. This medicine can harm or kill your unborn baby.

Known Drug Interactions

7.4 Dual Blockade of the Renin-Angiotensin System (RAS) Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Do not coadminister aliskiren with HYZAAR in patients with diabetes. Avoid use of aliskiren with HYZAAR in patients with renal impairment (GFR <60 mL/min).

Mechanism: These drugs work on the same pathway to lower blood pressure, and taking both can lead to dangerously high potassium or sudden kidney failure.

moderate lithium

( 7.1 ) Lithium: Risk of lithium toxicity. 7.2 Lithium Increases in serum lithium concentrations and lithium toxicity have been reported with concomitant use of angiotensin II receptor antagonists or thiazide diuretics. Monitor lithium levels in patients receiving HYZAAR and lithium.

Mechanism: These blood pressure medications can cause the amount of lithium in your body to rise to dangerous levels. This happens because the drugs change how your kidneys get rid of lithium.

The Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial enrolled 1448 patients with type 2 diabetes, elevated urinary-albumin-to-creatinine ratio, and decreased estimated glomerular filtration rate (GFR 30 to 89.9 mL/min), randomized them to lisinopril or placebo on a background of losartan therapy and followed them for a median of 2.2 years. Patients receiving the combination of losartan and lisinopril did not obtain any additional benefit compared to monotherapy for the combined endpoint of decline in GFR, end-stage renal disease, or death, but experienced an increased...

Mechanism: Combining these two similar types of blood pressure drugs does not offer extra protection for your heart or kidneys and increases the risk of side effects.

( 7.5 ) 7.1 Agents Increasing Serum Potassium Coadministration of losartan with other drugs that raise serum potassium levels may result in hyperkalemia. 7.3 Non-Steroidal Anti-Inflammatory Agents Including Selective Cyclooxygenase-2 Inhibitors Losartan Potassium In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including losartan) may result in deterioration of renal function, including possible acute renal...

Mechanism: Taking these medications together can cause your potassium levels to become dangerously high or lead to kidney problems.

Hydrochlorothiazide The administration of a non-steroidal anti-inflammatory agent including a selective COX-2 inhibitor can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Monitor renal function periodically in patients receiving hydrochlorothiazide, losartan, and NSAID therapy. 7.5 The Use of Hydrochlorothiazide with Other Drugs When administered concurrently, the following drugs may interact with thiazide diuretics [see Clinical Pharmacology (12.3) ]: Antidiabetic drugs (oral agents and insulin) — dosage adjustment of the...

Mechanism: Pain relievers like NSAIDs can stop blood pressure medicines and water pills from working as well as they should. Taking these together can also put extra stress on your kidneys.

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This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.

Common Questions

Can I take Hyzaar if I have diabetes?
You should not take Hyzaar with aliskiren if you have diabetes.
Can I drink alcohol while taking Hyzaar?
Talk to your doctor about drinking alcohol while taking Hyzaar, as it may lower your blood pressure too much.
What should I do if I feel dizzy after taking Hyzaar?
If you feel dizzy, sit or lie down until the dizziness passes. Tell your doctor if dizziness continues.
Can Hyzaar affect my kidneys?
Yes, Hyzaar can affect your kidneys, especially if you have kidney problems. Your doctor will monitor your kidney function.
Does Hyzaar interact with other medications?
Yes, Hyzaar can interact with other medications. Tell your doctor about all the medicines you take, including over-the-counter drugs and supplements.
How long does it take for Hyzaar to lower my blood pressure?
It may take several weeks for Hyzaar to lower your blood pressure. Continue taking the medicine as prescribed, even if you feel well.
Can I stop taking Hyzaar if my blood pressure is normal?
Do not stop taking Hyzaar without talking to your doctor first. Stopping suddenly can cause your blood pressure to rise.
Will Hyzaar cure my high blood pressure?
Hyzaar helps control high blood pressure, but it is not a cure. You may need to take it for the rest of your life.
Are there any foods I should avoid while taking Hyzaar?
Talk to your doctor about your diet. They may recommend limiting your sodium intake.
Can Hyzaar cause any changes in my potassium levels?
Yes, Hyzaar can cause changes in your potassium levels. Your doctor will monitor your potassium levels with blood tests.
What are the common side effects of hydrochlorothiazide/losartan?
The registry lists Dizziness, Upper respiratory infection, Cough, Back pain among the most-reported FAERS reaction terms for hydrochlorothiazide/losartan. The compiled record contains 75,364 FDA adverse-event reports. These counts are not an individual symptom assessment.
Does hydrochlorothiazide/losartan interact with other medications?
The registry has 7 documented interaction rows for hydrochlorothiazide/losartan. Notable source-record pairings include aliskiren, lithium, lisinopril. These rows are not a complete medication review.
What drug class is hydrochlorothiazide/losartan?
hydrochlorothiazide/losartan belongs to the Thiazide Diuretic / ARB Combination drug class. It requires a prescription (Rx). Hyzaar is used to treat high blood pressure.
What pregnancy or breastfeeding source fields are listed for hydrochlorothiazide/losartan?
The FDA label for hydrochlorothiazide/losartan contains product-specific pregnancy or breastfeeding language. PlainMeds does not apply that source text to an individual.

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What the FDA Data Shows for hydrochlorothiazide/losartan

The FDA label for hydrochlorothiazide/losartan (sold under brand names such as Hyzaar) classifies it as a prescription-only medication in the Thiazide Diuretic / ARB Combination class. Hyzaar is used to treat high blood pressure. Official labeling lists 4 commonly reported side effects, including Dizziness, Upper respiratory infection, Cough.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 75,364 voluntary reports. The database also lists 7 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS.

Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.

Last updated: November 26, 2025

PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.

Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.

All federal data sources used on this page