Overview
DESCRIPTION: Triamterene and hydrochlorothiazide tablets, USP combine triamterene, a potassium-conserving diuretic, with the natriuretic agent, hydrochlorothiazide. Each Triamterene and hydrochlorothiazide tablet,USP contains: Triamterene, USP ............................................................................... 75 mg Hydrochlorothiazide, USP .............................................
Mechanism of Action
CLINICAL PHARMACOLOGY: Triamterene and hydrochlorothiazide tablets are diuretic, antihypertensive drug product, principally due to its hydrochlorothiazide component; the triamterene component of triamterene and hydrochlorothiazide tablets reduces the excessive potassium loss which may occur with hydrochlorothiazide use. Hydrochlorothiazide: Hydrochlorothiazide is a diuretic and antihypertensive agent. It blocks the renal tubular absorption of sodium and chloride ions. This natriuresis and diuresis is accompanied by a secondary loss of potassium and bicarbonate. Onset of hydrochlorothiazide’s diuretic effect occurs within 2 hours and the peak action takes place in 4 hours. Diuretic activity persists for approximately 6 to 12 hours.
Indications
- 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.
Common Doses
- 37.5 mg
- 25 mg
- 75 mg
- 50 mg
Dosage
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.
Black Box 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...
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. 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.
Side Effects
- 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.
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.