Drug Facts
Composition & Profile
Identifiers & Packaging
HOW SUPPLIED Triamterene and hydrochlorothiazide capsules, USP containing 25 mg hydrochlorothiazide and 37.5 mg triamterene. They are supplied as follows: Unit-of-use bottles of 100 - NDC 33342-467-11 Bottles of 1,000 - NDC 33342-467-44 Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) (see USP Controlled Room Temperature). Protect from light. Dispense in a tight, light-resistant container. Manufactured for: Macleods Pharma USA, INC. Princeton, NJ 08540 Manufactured by: Macleods Pharmaceuticals Ltd. Baddi, Himachal Pradesh-174101, INDIA All trademarks are the property of their respective owners. Revised: February 2025; PACKAGE LABEL.PRINCIPAL DISPLAY PANEL Bottle of 100 Tablets NDC 33342-467-11 37.5mg/ 25 mg Rx only Bottle of 1000 Tablets NDC 33342-467-44 37.5mg/ 25 mg Rx only 123 543
- HOW SUPPLIED Triamterene and hydrochlorothiazide capsules, USP containing 25 mg hydrochlorothiazide and 37.5 mg triamterene. They are supplied as follows: Unit-of-use bottles of 100 - NDC 33342-467-11 Bottles of 1,000 - NDC 33342-467-44 Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) (see USP Controlled Room Temperature). Protect from light. Dispense in a tight, light-resistant container. Manufactured for: Macleods Pharma USA, INC. Princeton, NJ 08540 Manufactured by: Macleods Pharmaceuticals Ltd. Baddi, Himachal Pradesh-174101, INDIA All trademarks are the property of their respective owners. Revised: February 2025
- PACKAGE LABEL.PRINCIPAL DISPLAY PANEL Bottle of 100 Tablets NDC 33342-467-11 37.5mg/ 25 mg Rx only Bottle of 1000 Tablets NDC 33342-467-44 37.5mg/ 25 mg Rx only 123 543
Overview
Each Triamterene and hydrochlorothiazide capsule, USP for oral use, with opaque red cap and opaque white body, contains hydrochlorothiazide 25 mg and triamterene 37.5 mg, and is imprinted with "T 49" on the body with black ink. Hydrochlorothiazide is a diuretic/antihypertensive agent and triamterene is an antikaliuretic agent. Hydrochlorothiazide, USP is slightly soluble in water. It is soluble in dilute ammonia, dilute aqueous sodium hydroxide, and dimethylformamide. It is sparingly soluble in methanol. Hydrochlorothiazide, USP is 6-chloro-3,4-dihydro-2H-1, 2, 4-benzothiadiazine-7-sulfonamide 1,1-dioxide, and its structural formula is: At 50°C, triamterene, USP is practically insoluble in water (less than 0.1%). It is soluble in formic acid, sparingly soluble in methoxyethanol, and very slightly soluble in alcohol. Triamterene, USP is 2, 4, 7-triamino-6-phenylpteridine and its structural formula is: Inactive ingredients consist of microcrystalline cellulose, lactose monohydrate, sodium starch glycolate, cetylpyridinium chloride, povidone, polysorbate 80, glycine, magnesium stearate. The capsule shells have the following inactive ingredients: gelatin, D&C Red No. 33, FD&C Yellow No. 6 and titanium dioxide. The black ink has the following inactive ingredients: shellac, propylene glycol, black iron oxide E172 and potassium hydroxide. FDA approved dissolution test specifications differ from USP 178 159
Indications & Usage
INDICATIONS & USAGE 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 capsules are indicated for the treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone. Triamterene and hydrochlorothiazide capsules are also indicated for those patients who require a thiazide diuretic and in whom the development of hypokalemia cannot be risked. Triamterene and hydrochlorothiazide capsules may be used alone or as an adjunct to other antihypertensive drugs, such as beta-blockers. Since triamterene and hydrochlorothiazide capsules may enhance the action of these agents, dosage adjustments may be necessary. Usage in Pregnancy: The routine use of diuretics in an otherwise healthy woman is inappropriate and exposes mother and fetus to unnecessary hazard. Diuretics do not prevent development of toxemia of pregnancy, and there is no satisfactory evidence that they are useful in the treatment of developed toxemia. Edema during pregnancy may arise from pathological causes or from the physiologic and mechanical consequences of pregnancy. Diuretics are indicated in pregnancy when edema is due to pathologic causes, just as they are in the absence of pregnancy. Dependent edema in pregnancy resulting from restriction of venous return by the expanded uterus is properly treated through elevation of the lower extremities and use of support hose; use of diuretics to lower intravascular volume in this case is illogical and unnecessary. There is hypervolemia during normal pregnancy which is harmful to neither the fetus nor the mother (in the absence of cardiovascular disease), but which is associated with edema, including generalized edema in the majority of pregnant women. If this edema produces discomfort, increased recumbency will often provide relief. In rare instances this edema may cause extreme discomfort which is not relieved by rest. In these cases, a short course of diuretics may provide relief and may be appropriate.
Dosage & Administration
DOSAGE & ADMINISTRATION The usual dose of Triamterene and hydrochlorothiazide capsules, USP is 1 or 2 capsules given once daily, with appropriate monitoring of serum potassium and of the clinical effect (see WARNINGS, Hyperkalemia).
Warnings & Precautions
WARNINGS Hyperkalemia: Abnormal elevation of serum potassium levels (greater than or equal to 5.5 mEq/liter) can occur with all potassium-sparing diuretic combinations, including triamterene and hydrochlorothiazide. Hyperkalemia is more likely to occur in patients with renal impairment and diabetes (even without evidence of renal impairment), and in the elderly or severely ill. Since uncorrected hyperkalemia may be fatal, serum potassium levels must be monitored at frequent intervals especially in patients first receiving triamterene and hydrochlorothiazide, when dosages are changed, or with any illness that may influence renal function. If hyperkalemia is suspected (warning signs include paresthesias, muscular weakness, fatigue, flaccid paralysis of the extremities, bradycardia, and shock), an electrocardiogram (ECG) should be obtained. However, it is important to monitor serum potassium levels because hyperkalemia may not be associated with ECG changes. If hyperkalemia is present, triamterene and hydrochlorothiazide capsules should be discontinued immediately and a thiazide alone should be substituted. If the serum potassium exceeds 6.5 mEq/L more vigorous therapy is required. The clinical situation dictates the procedures to be employed. These include the intravenous administration of calcium chloride solution, sodium bicarbonate solution, and/or the oral or parenteral administration of glucose with a rapid-acting insulin preparation. Cationic exchange resins such as sodium polystyrene sulfonate may be orally or rectally administered. Persistent hyperkalemia may require dialysis. The development of hyperkalemia associated with potassium-sparing diuretics is accentuated in the presence of renal impairment (see CONTRAINDICATIONS). Patients with mild renal functional impairment should not receive this drug without frequent and continuing monitoring of serum electrolytes. Cumulative drug effects may be observed in patients with impaired renal function. The renal clearances of hydrochlorothiazide and the pharmacologically active metabolite of triamterene, the sulfate ester of hydroxytriamterene, have been shown to be reduced and the plasma levels increased following administration of triamterene and hydrochlorothiazide capsules to elderly patients and patients with impaired renal function. Hyperkalemia has been reported in diabetic patients with the use of potassium-sparing agents even in the absence of apparent renal impairment. Accordingly, serum electrolytes must be frequently monitored if triamterene and hydrochlorothiazide capsules are used in diabetic patients. Metabolic or Respiratory Acidosis: Potassium-sparing therapy should also be avoided in severely ill patients in whom respiratory or metabolic acidosis may occur. Acidosis may be associated with rapid elevations in serum potassium levels. If triamterene and hydrochlorothiazide is employed, frequent evaluations of acid/base balance and serum electrolytes are necessary. Acute Myopia and Secondary Angle-Closure Glaucoma: Hydrochlorothiazide, a sulfonamide, can cause an idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma. Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue hydrochlorothiazide as rapidly as possible. Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled. Risk factors for developing acute angle-closure glaucoma may include a history of sulfonamide or penicillin allergy.
Contraindications
Antikaliuretic Therapy and Potassium Supplementation: Triamterene and hydrochlorothiazide should not be given to patients receiving other potassium-sparing agents such as spironolactone, amiloride, or other formulations containing triamterene. Concomitant potassium-containing salt substitutes should also not be used. Potassium supplementation should not be used with triamterene and hydrochlorothiazide capsules except in severe cases of hypokalemia. Such concomitant therapy can be associated with rapid increases in serum potassium levels. If potassium supplementation is used, careful monitoring of the serum potassium level is necessary. Impaired Renal Function: Triamterene and hydrochlorothiazide is contraindicated in patients with anuria, acute and chronic renal insufficiency, or significant renal impairment. Hypersensitivity: Hypersensitivity to either drug in the preparation or to other sulfonamide-derived drugs is a contraindication. Hyperkalemia: Triamterene and hydrochlorothiazide should not be used in patients with pre-existing elevated serum potassium.
Adverse Reactions
Adverse effects are listed in decreasing order of severity. Hypersensitivity: Anaphylaxis, rash, urticaria, subacute cutaneous lupus erythematosus-like reactions, photosensitivity. Cardiovascular: Arrhythmia, postural hypotension. Metabolic: Diabetes mellitus, hyperkalemia, hypokalemia, hyponatremia, acidosis, hypercalcemia, hyperglycemia, glycosuria, hyperuricemia, hypochloremia. Gastrointestinal: Jaundice and/or liver enzyme abnormalities, pancreatitis, nausea and vomiting, diarrhea, constipation, abdominal pain. Renal: Acute renal failure (one case of irreversible renal failure has been reported), interstitial nephritis, renal stones composed primarily of triamterene, elevated BUN, and serum creatinine, abnormal urinary sediment. Hematologic: Leukopenia, thrombocytopenia and purpura, megaloblastic anemia. Musculoskeletal: Muscle cramps. Central Nervous System: Weakness, fatigue, dizziness, headache, dry mouth. Miscellaneous: Impotence, sialadenitis . Thiazides alone have been shown to cause the following additional adverse reactions: Central Nervous System: Paresthesias, vertigo. Ophthalmic: Xanthopsia, transient blurred vision. Respiratory: Allergic pneumonitis, pulmonary edema, respiratory distress. Other: Necrotizing vasculitis, exacerbation of lupus. Hematologic: Aplastic anemia, agranulocytosis, hemolytic anemia. Neonate and infancy: Thrombocytopenia and pancreatitis–rarely, in newborns whose mothers have received thiazides during pregnancy. Skin: Erythema multiforme, including Stevens-Johnson syndrome; exfoliative dermatitis, including toxic epidermal necrolysis. 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.
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