Triamterene and hydrochlorothiazide

What Triamterene and hydrochlorothiazide is used for

Quoted from the “Indications and Usage” section of the FDA-approved label.

This fixed combination drug is not indicated for the initial therapy of edema or hypertension except in individuals in whom the development of hypokalemia cannot be risked. Triamterene and hydrochlorothiazide tablets are indicated for the treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone. …

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Label quoted: the one for the most common form (tablet, oral), Triamterene and Hydrochlorothiazide, Apotex Corp.; it covers 2 products in the FDA NDC Directory. The side effects, interactions, dosage and pregnancy quotes below come from this same label.

The FDA has 58 labels for products of this medicine (different makers and forms); uses can differ between them. Check the label that comes with your own medicine.

This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.

Conditions named on the label

These condition names appear word for word in the label’s “Indications and Usage” text (matched with a reviewed table). Each page lists hospitals whose own websites name the condition.

Related medical specialties

Boxed warning

A boxed warning (“black box”) is the FDA’s strongest warning on a drug label, for serious or life-threatening risks.

The label quoted above has no boxed warning.

31 of 58 FDA labels for this medicine have a boxed warning.

Triamterene and hydrochlorothiazide side effects

Quoted from the “Adverse Reactions” section of the FDA-approved label. Tell your doctor about any side effect that worries you.

Side effects observed in association with the use of triamterene and hydrochlorothiazide tablets, other combination products containing triamterene/hydrochlorothiazide, and products containing triamterene or hydrochlorothiazide include the following: Gastrointestinal: jaundice (intrahepatic cholestatic jaundice), pancreatitis, nausea, appetite disturbance, taste alteration, vomiting, diarrhea, constipation, anorexia, gastric irritation, cramping.

Read more of this section

Central Nervous System: drowsiness and fatigue, insomnia, headache, dizziness, dry mouth, depression, anxiety, vertigo, restlessness, paresthesias. Cardiovascular: tachycardia, shortness of breath and chest pain, orthostatic hypotension (may be aggravated by alcohol, barbiturates or narcotics). Renal: acute renal failure, acute interstitial nephritis, renal stones composed of triamterene in association with other calculus materials, urine discoloration. Hematologic: leukopenia, agranulocytosis, thrombocytopenia, aplastic anemia, hemolytic anemia and megaloblastosis. Ophthalmic: xanthopsia, transient blurred vision. Hypersensitivity: anaphylaxis, photosensitivity, rash, urticaria, purpura, necrotizing angiitis (vasculitis, cutaneous vasculitis), fever, respiratory distress including pneumonitis. Other: muscle cramps and weakness, decreased sexual performance and sialadenitis. Whenever adverse reactions are moderate to severe, therapy should be reduced or withdrawn. Altered Laboratory Findings Serum Electrolytes: hyperkalemia, hypokalemia, hyponatremia, hypomagnesemia, hypochloremia (see WARNINGS and PRECAUTIONS). Creatinine, Blood Urea Nitrogen: Reversible elevations in BUN and serum creatinine have been observed in hypertensive patients treated with triamterene and hydrochlorothiazide. Glucose: hyperglycemia, glycosuria and diabetes mellitus (see PRECAUTIONS). Serum Uric Acid, PBI and Calcium: (see PRECAUTIONS). Other: Elevated liver enzymes have been reported in patients receiving triamterene and hydrochlorothiazide. Postmarketing Experience Non-melanoma Skin Cancer Hydrochlorothiazide is associated with an increased risk of non-melanoma skin cancer. In a study conducted in the Sentinel System, increased risk was predominantly for squamous cell carcinoma (SCC) and in white patients taking large cumulative doses. The increased risk for SCC in the overall population was approximately 1 additional case per 16,000 patients per year, and for white patients taking a cumulative dose of ≥ 50,000 mg the risk increase was approximately 1 additional SCC case for every 6,700 patients per year.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Triamterene and hydrochlorothiazide drug interactions

Quoted from the “Drug Interactions” section of the FDA-approved label. Tell your pharmacist about every medicine, vitamin and herbal product you take.

Thiazides may add to or potentiate the action of other antihypertensive drugs. The thiazides may decrease arterial responsiveness to norepinephrine. This diminution is not sufficient to preclude effectiveness of the pressor agent for therapeutic use. Thiazides have also been shown to increase the responsiveness to tubocurarine. Lithium generally should not be given with diuretics because they reduce its renal clearance and add a high risk of lithium toxicity.

Read more of this section

Refer to the package insert on lithium before use of such concomitant therapy. Acute renal failure has been reported in a few patients receiving indomethacin and formulations containing triamterene and hydrochlorothiazide. Caution is therefore advised when administering non-steroidal anti-inflammatory agents with triamterene and hydrochlorothiazide. Potassium-sparing agents should be used very cautiously, if at all, in conjunction with angiotensin-converting enzyme (ACE) inhibitors due to a greatly increased risk of hyperkalemia. Serum potassium should be monitored frequently.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Triamterene and hydrochlorothiazide dosage

Quoted from the “Dosage and Administration” section of the FDA-approved label. Your own dose is the one your doctor prescribes: do not change it on your own.

Note: 37.5 mg/25 mg = 37.5 mg triamterene and 25 mg hydrochlorothiazide 75 mg/50 mg = 75 mg triamterene and 50 mg hydrochlorothiazide The usual dose of Triamterene and Hydrochlorothiazide 37.5 mg/25 mg is one or two tablets daily, given as a single dose, with appropriate monitoring of serum potassium (see WARNINGS). The usual dose of Triamterene and Hydrochlorothiazide 75 mg/50 mg is one tablet daily, with appropriate monitoring of serum potassium (see WARNINGS).

Read more of this section

There is no experience with the use of more than one 75 mg/50 mg tablet daily or more than two 37.5 mg/25 mg tablets daily. Clinical experience with the administration of two 37.5 mg/25 mg tablets daily in divided doses (rather than as a single dose) suggests an increased risk of electrolyte imbalance and renal dysfunction. Patients receiving 50 mg of hydrochlorothiazide who become hypokalemic may be transferred to 75 mg/50 mg product directly. Patients receiving 25 mg hydrochlorothiazide who become hypokalemic may be transferred to a 37.5 mg triamterene/25 mg hydrochlorothiazide directly. In patients requiring hydrochlorothiazide therapy and in whom hypokalemia cannot be risked, therapy may be initiated with 37.5 mg/25 mg of triamterene and hydrochlorothiazide. If an optimal blood pressure response is not obtained with 37.5 mg/25 mg of triamterene and hydrochlorothiazide, the dose should be increased to two 37.5 mg/25 mg tablets daily as a single dose, or one 75 mg/50 mg tablet daily. If blood pressure still is not controlled, another antihypertensive agent may be added (see PRECAUTIONS, Drug Interactions). Clinical studies have shown that patients taking less bioavailable formulations of triamterene and hydrochlorothiazide in daily doses of 25 mg to 50 mg hydrochlorothiazide and 50 mg to 100 mg triamterene may be safely changed to one 37.5 mg/25 mg of triamterene and hydrochlorothiazide daily. All patients changed from less bioavailable formulations to triamterene and hydrochlorothiazide should be monitored clinically and for serum potassium after the transfer.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Triamterene and hydrochlorothiazide in pregnancy

Quoted from the pregnancy part of the FDA-approved label. Ask your doctor before you take any medicine while pregnant or planning a pregnancy.

Teratogenic Effects Triamterene and hydrochlorothiazide Animal reproduction studies to determine the potential for fetal harm by triamterene and hydrochlorothiazide have not been conducted. Nevertheless, a One Generation Study in the rat approximated triamterene and hydrochlorothiazide's composition by using a 1:1 ratio of triamterene to hydrochlorothiazide (30:30 mg/kg/day).

Read more of this section

There was no evidence of teratogenicity at those doses that were, on a body- weight basis, 15 and 30 times, respectively, the MRHD, and, on the basis of body-surface area, 3.1 and 6.2 times, respectively, the MRHD. The safe use of triamterene and hydrochlorothiazide in pregnancy has not been established since there are no adequate and well controlled studies with triamterene and hydrochlorothiazide in pregnant women. Triamterene and hydrochlorothiazide should be used during pregnancy only if the potential benefit justifies the risk to the fetus. Triamterene Reproduction studies have been performed in rats at doses as high as 20 times the Maximum Recommended Human Dose (MRHD) on the basis of body-weight, and 6 times the MRHD on the basis of body-surface area without evidence of harm to the fetus due to triamterene. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Hydrochlorothiazide Hydrochlorothiazide was orally administered to pregnant mice and rats during respective periods of major organogenesis at doses up to 3000 and 1000 mg/kg/day, respectively. At these doses, which are multiples of the MRHD equal to 3000 for mice and 1000 for rats, based on body-weight, and equal to 282 for mice and 206 for rats, based on body-surface area, there was no evidence of harm to the fetus. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Nonteratogenic Effects Thiazides and triamterene have been shown to cross the placental barrier and appear in cord blood. The use of thiazides and triamterene in pregnant women requires that the anticipated benefits be weighed against possible hazards to the fetus. These hazards include fetal or neonatal jaundice, pancreatitis, thrombocytopenia, and possibly other adverse reactions that have occurred in the adult.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Triamterene and hydrochlorothiazide and breastfeeding

Quoted from the nursing mothers / lactation part of the FDA-approved label.

Thiazides and triamterene in combination have not been studied in nursing mothers. Triamterene appears in animal milk and this may occur in humans. Thiazides are excreted in human breast milk. If use of the combination drug product is deemed essential, the patient should stop nursing.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

When Triamterene and hydrochlorothiazide should not be used

Quoted from the “Contraindications” section of the FDA-approved label.

Hyperkalemia Triamterene and hydrochlorothiazide should not be used in the presence of elevated serum potassium levels (greater than or equal to 5.5 mEq/liter). If hyperkalemia develops, this drug should be discontinued, and a thiazide alone should be substituted.

Read more of this section

Antikaliuretic Therapy or Potassium Supplementation Triamterene and hydrochlorothiazide should not be given to patients receiving other potassium-conserving agents such as spironolactone, amiloride hydrochloride or other formulations containing triamterene. Concomitant potassium supplementation in the form of medication, potassium-containing salt substitute or potassium-enriched diets should also not be used. Impaired Renal Function Triamterene and hydrochlorothiazide is contraindicated in patients with anuria, acute and chronic renal insufficiency or significant renal impairment. Hypersensitivity Triamterene and hydrochlorothiazide should not be used in patients who are hypersensitive to triamterene or hydrochlorothiazide or other sulfonamide-derived drugs.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Triamterene and hydrochlorothiazide overdose

Quoted from the “Overdosage” section of the FDA-approved label. If someone may have taken too much, call Poison Help at 1-800-222-1222 (or 911 in an emergency).

No specific data are available regarding triamterene and hydrochlorothiazide overdosage in humans and no specific antidote is available. Fluid and electrolyte imbalances are the most important concern. Excessive doses of the triamterene component may elicit hyperkalemia, dehydration, nausea, vomiting and weakness and possibly hypotension.

Read more of this section

Overdosing with hydrochlorothiazide has been associated with hypokalemia, hypochloremia, hyponatremia, dehydration, lethargy (may progress to coma) and gastrointestinal irritation. Treatment is symptomatic and supportive. Therapy with triamterene and hydrochlorothiazide should be discontinued. Induce emesis or institute gastric lavage. Monitor serum electrolyte levels and fluid balance. Institute supportive measures as required to maintain hydration, electrolyte balance, respiratory, cardiovascular and renal function.

— FDA label: Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026. Read the full label on DailyMed →

Forms and how it is given

Same medicine, other forms and combinations

Prescription medicine pages on this site that share an active ingredient with this one, from the FDA NDC Directory. A combination is a different medicine: ask your pharmacist before you switch.

Other medicines with one of these active ingredients

• HydrochlorothiazideInzirqo · 171 products
• Losartan potassium and hydrochlorothiazideHyzaar · 111 products
• Valsartan and hydrochlorothiazideDiovan Hct · 104 products
• Lisinopril and hydrochlorothiazideZestoretic · 95 products
• Olmesartan medoxomil and hydrochlorothiazideBenicar Hct · 81 products
• Olmesartan medoxomil / amlodipine besylate / hydrochlorothiazideTribenzor · 43 products
• Bisoprolol fumarate and hydrochlorothiazide42 products
• Irbesartan and hydrochlorothiazideAvalide · 31 products
• Amlodipine besylate valsartan hydrochlorothiazideExforge Hct · 30 products
• Telmisartan and hydrochlorothiazideMicardis Hct · 27 products
• Benazepril hydrochloride and hydrochlorothiazideLotensin Hct · 21 products
• Candesartan cilexetil and hydrochlorothiazideAtacand Hct · 16 products
• Metoprolol tartrate and hydrochlorothiazide14 products
• Quinapril HCL and hydrochlorothiazide12 products
• Spironolactone and hydrochlorothiazide12 products
• TriamtereneDyrenium · 9 products
• Enalapril maleate and hydrochlorothiazideVaseretic · 5 products
• Captopril and hydrochlorothiazide4 products
• Fosinopril sodium and hydrochlorothiazide4 products
• Amiloride hydrochloride and hydrochlorothiazide1 product

Companies that list this medicine

Labelers in the FDA NDC Directory: the company named on the package (maker or distributor), with the number of prescription products.

• Bryant Ranch Prepack11 products
• A-S Medication Solutions8 products
• Northwind Health Company, LLC6 products
• NuCare Pharmaceuticals, Inc.5 products
• BluePoint Laboratories4 products
• Aphena Pharma Solutions - Tennessee, LLC4 products
• Preferred Pharmaceuticals Inc.3 products
• Proficient Rx LP3 products
• Zydus Lifesciences Limited3 products
• Remedyrepack Inc.3 products
• Zydus Pharmaceuticals USA Inc.3 products
• PD-Rx Pharmaceuticals, Inc.3 products
• Apotex Corp.2 products
• Advagen Pharma Ltd2 products
• Actavis Pharma, Inc.2 products
• Chartwell RX, LLC1 product
• Sandoz Inc1 product
• American Health Packaging1 product
• Viona Pharmaceuticals Inc1 product
• Macleods Pharmaceuticals Limited1 product
• St. Mary's Medical Park Pharmacy1 product
• Golden State Medical Supply, Inc.1 product

FDA approval history

• ANDA: Abbreviated New Drug Application: how a generic version is approved.

Generic approvals (9)

• ANDA071251Apotex Inc · December 8, 1987
• ANDA071851Watson Labs · November 30, 1988
• ANDA073449Watson Labs · September 23, 1993
• ANDA074821Sandoz · June 5, 1997
• ANDA201407Lannett Co Inc · December 9, 2011
• ANDA208360Zydus Pharms · June 29, 2018
• ANDA208358Cadila · February 11, 2019
• ANDA216211Rubicon Research · February 23, 2022
• ANDA214611Macleods Pharms · January 28, 2025

Shortage status

The FDA drug shortage list does not show these products.

FDA Drug Shortages database →

Recalls

No recall linked to these products (by their NDC code) appears in the FDA enforcement reports.

Official identifiers

Next steps

• Find a pharmacy near youAsk which price applies to you and whether your product is affected by a recall
• Latest FDA drug recallsAll medicines, newest first
• High blood pressureCondition named on the label: hospitals that treat it
• Bryant Ranch PrepackMaker or distributor
• A-S Medication SolutionsMaker or distributor
• Northwind Health Company, LLCMaker or distributor
• All prescription drugs A to ZSearch by generic, brand or Spanish name

Sources

1. FDA-approved label on DailyMed (National Library of Medicine) — Triamterene and Hydrochlorothiazide, Apotex Corp., effective February 17, 2026; via openFDA, FDA data exported October 30, 2026, retrieved October 31, 2026
2. NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
3. Drugs@FDA (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
4. Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
5. Drug shortages (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026

openFDA data is provided by the FDA as is; it may be incomplete. Always rely on the label that comes with your medicine. FDA Enforcement Report search →

Report an error → · Information for medicine makers