Losartan and Hydrochlorothiazide Interaction

Drug interaction information between Losartan and Hydrochlorothiazide.

Losartan and Hydrochlorothiazide have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Losartan and Hydrochlorothiazide. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.

Drug A

Losartan

Angiotensin II Receptor Blocker (ARB)

Drug B

Hydrochlorothiazide

Thiazide Diuretic / ACE Inhibitor Combination

How They Interact

Combining these two drugs can cause your potassium levels to rise and may lead to serious kidney problems without providing extra benefits.

FDA Label Information

The VA NEPHRON trial enrolled 1448 patients with type 2 diabetes, elevated urinary-albumin-to-creatinine ratio, and decreased estimated glomerular filtration rate (GFR 30 mL/min 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 state renal disease, or death, but experienced an increased incidence of hyperkalemia and acute kidney...

Frequently Asked Questions

What SPL severity band is on file for Losartan + Hydrochlorothiazide/Lisinopril?

Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.

Which drug in this pair has the larger labeled-interaction portfolio?

Hydrochlorothiazide has 13 labeled pairs on file vs Losartan's 10. In the minor band specifically: Losartan has 8 (also Fluconazole, Glecaprevir/Pibrentasvir, Hydrochlorothiazide, Hydrochlorothiazide/Losartan); Hydrochlorothiazide has 12 (also Lisinopril, Hydrochlorothiazide, Spironolactone, Propranolol).

What mechanism field is on file for Losartan and Hydrochlorothiazide/Lisinopril?

Combining these two drugs can cause your potassium levels to rise and may lead to serious kidney problems without providing extra benefits.

Hydrochlorothiazide's labeled portfolio outnumbers Losartan

SPL source-record counts only. This page's band is minor · classes on file: Losartan (Angiotensin II Receptor Blocker (ARB)); Hydrochlorothiazide (Thiazide Diuretic / ACE Inhibitor Combination).

Losartan

1 major · 1 moderate · 8 minor · 10 total

Hydrochlorothiazide

1 major · 0 moderate · 12 minor · 13 total

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.