What the label lists and what reports show
Hydrochlorothiazide and olmesartan side effects
Hydrochlorothiazide and olmesartan's FDA label: “Most common adverse reactions (incidence ≥2%) are nausea, hyperuricemia, dizziness, and upper respiratory infection ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Cosette Pharmaceuticals, Inc.” FAERS holds 7,574 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is sprue-like enteropathy (2,397 reports).
- Generic listed
- Boxed warning
Check it at the source: the hydrochlorothiazide and olmesartan FDA label on DailyMed (effective March 10, 2026, Cosette Pharmaceuticals, Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence ≥2%) are nausea, hyperuricemia, dizziness, and upper respiratory infection ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Cosette Pharmaceuticals, Inc.
Table 1: Adverse Reactions in a Factorial Trial of Patients with Hypertension
| Reaction | Olmesartan/HCTZ (N=247) (%) | Olmesartan (N=125) (%) | HCTZ (N=88) (%) | Placebo (N=42) (%) |
|---|---|---|---|---|
| Nausea | 3 | 2 | 1 | 0 |
| Hyperuricemia | 4 | 0 | 2 | 2 |
| Dizziness | 9 | 1 | 8 | 2 |
| Upper Respiratory Infection | 7 | 6 | 7 | 0 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following adverse reactions with BENICAR HCT are described elsewhere: Hypotension in Volume- or Salt-Depleted Patients [see Warnings and Precautions (5.2) ] Impaired Renal Function [see Warnings and Precautions (5.3) ] Hypersensitivity Reactions [see Warnings and Precautions (5.4) ] Electrolyte and Metabolic Imbalances [see Warnings and Precautions (5.5) ] Acute Myopia and Secondary Angle-Closure Glaucoma [see Warnings and Precautions (5.6) ] Systemic Lupus Erythematosus [see Warnings and Precautions (5.7) ] Sprue-Like Enteropathy [see Warnings and Precautions (5.8) ] Most common adverse reactions (incidence ≥2%) are nausea, hyperuricemia, dizziness, and upper respiratory infection ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Cosette Pharmaceuticals, Inc. at 1-800-922-1038 or FDA at 1-800-332-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. Olmesartan medoxomil and hydrochlorothiazide The concomitant use of olmesartan medoxomil and hydrochlorothiazide was evaluated for safety in 1243 hypertensive patients. …
Source: FDA drug label, Cosette Pharmaceuticals, Inc., effective March 10, 2026 (SPL set a90915ca-f9d3-4fff-8370-d5dc4cdfc521), via openFDA; the full label on DailyMed
What do FAERS reports show?
7,574 reports list hydrochlorothiazide and olmesartan among the medicines taken, each a report of something that happened, not proof the medicine caused it; 190 are coded as a death and 3,501 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Reports rose sharply in 2018 (1,476, against a median of 86 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 24 reactions below, 6 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Hydrochlorothiazide and olmesartan: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions