Triamterene (6 brand names, 2 dosage forms, 1 route)
Available dosage forms: TABLET, CAPSULE.
Routes of administration: ORAL.
Brand Names
- DYAZIDE
- DYRENIUM
- MAXZIDE
- MAXZIDE-25
- TRIAMTERENE
- TRIAMTERENE AND HYDROCHLOROTHIAZIDE
Boxed Warning
WARNINGS: Hyperkalemia:Abnormal elevation of serum potassium levels (greater than or equal to 5.5 mEq/liter) can occur with all potassium-conserving diuretic combinations, including triamterene and hydrochlorothiazide. Hyperkalemia is more likely to occur in patients with renal impairment, diabetes (even without evidence of renal impairment), or elderly or severely ill patients. 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.
Indications and Usage
INDICATIONS AND 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 is 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.). 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.
Dosage and Administration
DOSAGE AND ADMINISTRATION:The usual dose of triamterene and hydrochlorothiazide tablets 37.5mg/25mg 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 tablets 75mg/ 50 mg is one tablet daily, with appropriate monitoring of serum potassium (see WARNINGS). There is no experience with the use of more than one triamterene and hydrochlorothiazide tablet 75mg/50mg daily or more than two triamterene and hydrochlorothiazide tablets 37.5mg/25mg daily. Clinical experience with the administration of two triamterene and hydrochlorothiazide tablets 37.5mg/25mg 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 75mg/50mg directly. Patients receiving 25 mg hydrochlorothiazide who become hypokalemic may be transferred to triamterene and hydrochlorothiazide tablets 37.5mg/25mg directly. In patients requiring hydrochlorothiazide therapy and in whom hypokalemia cannot be risked therapy may be initiated with triamterene and hydrochlorothiazide tablets 37.5mg/25mg. If an optimal blood pressure response is not obtained with triamterene and hydrochlorothiazide tablets 37.5mg/25mg, the dose should be increased to two triamterene and hydrochlorothiazide tablets 37.5mg/25mg daily as a single dose, or one triamterene and hydrochlorothiazide tablet 75mg/25mg 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 triamterene and hydrochlorothiazide tablets 37.5mg
Contraindications
CONTRAINDICATIONS: 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.
Adverse Reactions
ADVERSE REACTIONS:Side effects observed in association with the use of triamterene and hydrochlorothiazide, 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. Altered Laboratory Findings: Serum Electrolytes: hyperkalemia, hypokalemia, hyponatremia, hypomagnesemia, hypochloremia (see WARNINGSand 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. Pos
Drug Interactions
Drug Interactions: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. 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.
Overdosage
OVERDOSAGE: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.