displayName: DESCRIPTION SECTION
FDA Article Code: 34089-3
Triamterene and hydrochlorothiazide tablets combine triamterene, a potassium-conserving diuretic with the natriuretic agent hydrochlorothiazide. Each tablet for oral administration contains 37.5 mg triamterene and 25 mg hydrochlorothiazide or 75 mg triamterene and 50 mg hydrochlorothiazide. Inactive ingredients include croscarmellose sodium, D & C Yellow #10 Aluminum Lake, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polysorbate 80, and sodium bicarbonate. The 37.5 mg/25 mg tablet also contains FD & C Blue #1 Aluminum Lake.
Triamterene is 2,4,7-triamino-6-phenylpteridine. Triamterene is practically insoluble in water, benzene, chloroform, ether and dilute alkali hydroxides. It is soluble in formic acid and sparingly soluble in methoxyethanol. Triamterene is very slightly soluble in acetic acid, alcohol and dilute mineral acids. Its molecular weight is 253.27. Its structural formula is:
Hydrochlorothiazide is 6-chloro-3,4-dihydro-2H-1,2,4, benzothiadiazine-7-sulfonamide 1, 1-dioxide. Hydrochlorothiazide is slightly soluble in water and freely soluble in sodium hydroxide solution, n-butylamine and dimethylformamide. It is sparingly soluble in methanol and insoluble in ether, chloroform and dilute mineral acids. Its molecular weight is 297.73. Its structural formula is:
displayName: CLINICAL PHARMACOLOGY SECTION
FDA Article Code: 34090-1
Triamterene and hydrochlorothiazide is a diuretic, antihypertensive drug product, principally due to its hydrochlorothiazide component; the triamterene component reduces the excessive potassium loss which may occur with hydrochlorothiazide use.
INDICATIONS AND USAGE
displayName: INDICATIONS & USAGE SECTION
FDA Article Code: 34067-9
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 may be used alone or in combination with other antihypertensive drugs such as beta-blockers. Since triamterene and hydrochlorothiazide may enhance the actions of these drugs, dosage adjustments may be necessary.
- Triamterene and hydrochlorothiazide tablets are indicated for the treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone.
- Triamterene and hydrochlorothiazide is also indicated for those patients who require a thiazide diuretic and in whom the development of hypokalemia cannot be risked (e.g., patients on concomitant digitalis preparations, or with a history of cardiac arrhythmias, etc.).
displayName: ADVERSE REACTIONS SECTION
FDA Article Code: 34084-4
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.
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.
displayName: OVERDOSAGE SECTION
FDA Article Code: 34088-5
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. 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.
DOSAGE AND ADMINISTRATION
displayName: DOSAGE & ADMINISTRATION SECTION
FDA Article Code: 34068-7
The usual dose of triamterene and hydrochlorothiazide tablets 37.5 mg/25 mg is one or two tablets daily, given as a single dose, with appropriate monitoring of serum potassium (see
). The usual dose of triamterene and hydrochlorothiazide tablets, 75 mg/50 mg, is one tablet daily, with appropriate monitoring of serum potassium (see
). There is no experience with the use of more than one triamterene and hydrochlorothiazide tablet 75 mg/50 mg daily or more than two triamterene and hydrochlorothiazide tablets 37.5 mg/25 mg daily. Clinical experience with the administration of two triamterene and hydrochlorothiazide tablets 37.5 mg/25 mg 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 triamterene and hydrochlorothiazide tablets 75 mg/50 mg directly. Patients receiving 25 mg hydrochlorothiazide who become hypokalemic may be transferred to one triamterene and hydrochlorothiazide tablet 37.5 mg/25 mg directly.
In patients requiring hydrochlorothiazide therapy and in whom hypokalemia cannot be risked, therapy may be initiated with triamterene and hydrochlorothiazide tablets 37.5 mg/25 mg. If an optimal blood pressure response is not obtained with this product the dose should be increased to two tablets daily as a single dose, or to one triamterene and hydrochlorothiazide tablet 75 mg/50 mg daily. If blood pressure still is not controlled, another antihypertensive agent may be added (see
PRECAUTIONS: Drug Interactions
Clinical studies have shown patients taking less bioavailable formulations of triamterene and hydrochlorothiazide in daily doses of 25 to 50 mg of hydrochlorothiazide and 50 to 100 mg of triamterene may be safely changed to one triamterene and hydrochlorothiazide tablet 37.5 mg/25 mg daily. All patients changed from less bioavailable formulations of triamterene and hydrochlorothiazide to this tablet formulation should be monitored clinically and for serum potassium after the transfer.
displayName: HOW SUPPLIED SECTION
FDA Article Code: 34069-5
Triamterene and hydrochlorothiazide tablets, USP for oral administration are available as:
37.5 mg/25 mg: round, green, partial scored tablets, debossed GG 165 on one side and plain on the reverse side and supplied as:
75 mg/50 mg: round, yellow, scored tablets, debossed GG 172 on one side and plain on the reverse side and supplied as: