Source: FDA, National Drug Code (US) Revision Year: 2023
Anuria. Severe or progressive kidney disease or dysfunction, with the possible exception of nephrosis. Severe hepatic disease. Hypersensitivity to the drug or any of its components.
Dyrenium (triamterene) should not be used in patients with pre-existing elevated serum potassium, as is sometimes seen in patients with impaired renal function or azotemia, or in patients who develop hyperkalemia while on the drug. Patients should not be placed on dietary potassium supplements, potassium salts or potassium-containing salt substitutes in conjunction with Dyrenium.
Dyrenium should not be given to patients receiving other potassium-sparing agents, such as spironolactone, amiloride hydrochloride, or other formulations containing triamterene. Two deaths have been reported in patients receiving concomitant spironolactone and Dyrenium or Dyazide. Although dosage recommendations were exceeded in one case and in the other serum electrolytes were not properly monitored, these two drugs should not be given concomitantly.
Abnormal elevation of serum potassium levels (greater than or equal to 5.5 mEq/liter) can occur with all potassium-sparing agents, including Dyrenium. 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 receiving Dyrenium, when dosages are changed or with any illness that may influence renal function.
There have been isolated reports of hypersensitivity reactions; therefore, patients should be observed regularly for the possible occurrence of blood dyscrasias, liver damage or other idiosyncratic reactions.
Periodic BUN and serum potassium determinations should be made to check kidney function, especially in patients with suspected or confirmed renal insufficiency. It is particularly important to make serum potassium determinations in elderly or diabetic patients receiving the drug; these patients should be observed carefully for possible serum potassium increases.
If hyperkalemia is present or suspected, an electrocardiogram should be obtained. If the ECG shows no widening of the QRS or arrhythmia in the presence of hyperkalemia, it is usually sufficient to discontinue Dyrenium (triamterene) and any potassium supplementation, and substitute a thiazide alone. Sodium polystyrene sulfonate may be administered to enhance the excretion of excess potassium. The presence of a widened QRS complex or arrhythmia in association with hyperkalemia requires prompt additional therapy. For tachyarrhythmia, infuse 44 mEq of sodium bicarbonate or 10 mL of 10% calcium gluconate or calcium chloride over several minutes. For asystole, bradycardia or A-V block transvenous pacing is also recommended.
The effect of calcium and sodium bicarbonate is transient and repeated administration may be required. When indicated by the clinical situation, excess K+ may be removed by dialysis or oral or rectal administration of Sodium polystyrene sulfonate. Infusion of glucose and insulin has also been used to treat hyperkalemia.
Adverse effects are listed in decreasing order of frequency; however, the most serious adverse effects are listed first, regardless of frequency. All adverse effects occur rarely (that is, 1 in 1000, or less).
Hypersensitivity: anaphylaxis, rash, photosensitivity.
Metabolic: hyperkalemia, hypokalemia.
Renal: azotemia, elevated BUN and creatinine, renal stones, acute interstitial nephritis (rare), acute renal failure (one case of irreversible renal failure has been reported).
Gastrointestinal: jaundice and/or liver enzyme abnormalities, nausea and vomiting, diarrhea.
Hematologic: thrombocytopenia, megaloblastic anemia.
Central Nervous System: weakness, fatigue, dizziness, headache, dry mouth.
Dyrenium (triamterene) tends to conserve potassium rather than to promote the excretion as do many diuretics and, occasionally, can cause increases in serum potassium which, in some instances, can result in hyperkalemia. In rare instances, hyperkalemia has been associated with cardiac irregularities.
Electrolyte imbalance often encountered in such diseases as congestive heart failure, renal disease or cirrhosis may be aggravated or caused independently by any effective diuretic agent including Dyrenium. The use of full doses of a diuretic when salt intake is restricted can result in a low-salt syndrome.
Triamterene can cause mild nitrogen retention, which is reversible upon withdrawal of the drug, and is seldom observed with intermittent (every-other-day) therapy.
Triamterene may cause a decreasing alkali reserve, with the possibility of metabolic acidosis.
By the very nature of their illness, cirrhotics with splenomegaly sometimes have marked variations in their blood. Since triamterene is a weak folic acid antagonist, it may contribute to the appearance of megaloblastosis in cases where folic acid stores have been depleted. Therefore, periodic blood studies in these patients are recommended. They should also be observed for exacerbations of underlying liver disease.
Triamterene has elevated uric acid, especially in persons predisposed to gouty arthritis.
Triamterene has been reported in renal stones in association with other calculus components. Dyrenium should be used with caution in patients with histories of renal stones.
To help avoid stomach upset, it is recommended that the drug be taken after meals.
If a single daily dose is prescribed, it may be preferable to take it in the morning to minimize the effect of increased frequency of urination on nighttime sleep.
If a dose is missed, the patient should not take more than the prescribed dose at the next dosing interval.
Hyperkalemia will rarely occur in patients with adequate urinary output, but it is a possibility if large doses are used for considerable periods of time. If hyperkalemia is observed, Dyrenium (triamterene) should be withdrawn. The normal adult range of serum potassium is 3.5 to 5.0 mEq per liter, with 4.5 mEq often being used for a reference point. Potassium levels persistently above 6 mEq per liter require careful observation and treatment. Normal potassium levels tend to be higher in neonates (7.7 mEq per liter) than in adults.
Serum potassium levels do not necessarily indicate true body potassium concentration. A rise in plasma pH may cause a decrease in plasma potassium concentration and an increase in the intracellular potassium concentration. Because Dyrenium conserves potassium, it has been theorized that in patients who have received intensive therapy or been given the drug for prolonged periods, a rebound kaliuresis could occur upon abrupt withdrawal. In such patients, withdrawal of Dyrenium should be gradual.
Caution should be used when lithium and diuretics are used concomitantly because diuretic-induced sodium loss may reduce the renal clearance of lithium and increase serum lithium levels with risk of lithium toxicity. Patients receiving such combined therapy should have serum lithium levels monitored closely and the lithium dosage adjusted if necessary.
A possible interaction resulting in acute renal failure has been reported in a few subjects when indomethacin, a nonsteroidal anti-inflammatory agent, was given with triamterene. Caution is advised in administering nonsteroidal anti-inflammatory agents with triamterene.
The effects of the following drugs may be potentiated when given together with triamterene: antihypertensive medication, other diuretics, preanesthetic and anesthetic agents, skeletal muscle relaxants (non-depolarizing).
Potassium-sparing agents should be used with caution in conjunction with angiotensin-converting enzyme (ACE) inhibitors due to an increased risk of hyperkalemia.
The following agents, given together with triamterene, may promote serum potassium accumulation and possibly result in hyperkalemia because of the potassium-sparing nature of triamterene, especially in patients with renal insufficiency: blood from blood bank (may contain up to 30 mEq of potassium per liter of plasma or up to 65 mEq per liter of whole blood when stored for more than 10 days); low-salt milk (may contain up to 60 mEq of potassium per liter); potassium-containing medications (such as parenteral penicillin G potassium); salt substitutes (most contain substantial amounts of potassium).
Dyrenium (triamterene) may raise blood glucose levels; for adult-onset diabetes, dosage adjustments of hypoglycemic agents may be necessary during and/or after therapy; concurrent use with chlorpropamide may increase the risk of severe hyponatremia.
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.
Triamterene has been shown to cross the placental barrier and appear in cord blood. The use of triamterene in pregnant women requires that the anticipated benefits be weighed against possible hazards to the fetus. These possible hazards include adverse reactions which have occurred in the adult.
Triamterene has not been studied in nursing mothers. Triamterene appears in animal milk and is likely present in human milk. If use of the drug product is deemed essential, the patient should stop nursing.
Safety and effectiveness in pediatric patients have not been established.
Triamterene and quinidine have similar fluorescence spectra; thus, triamterene will interfere with the fluorescent measurement of quinidine.
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