Dyrenium

INDICATIONS AND USAGE Dyrenium (triamterene) is indicated in the treatment of edema associated with congestive heart failure, cirrhosis of the liver and the nephrotic syndrome; steroid-induced edema, idiopathic edema and edema due to secondary hyperaldosteronism. Dyrenium may be used alone or with other diuretics, either for its added diuretic effect or its potassium-sparing potential. It also promotes increased diuresis when patients prove resistant or only partially responsive to thiazides or other diuretics because of secondary hyperaldosteronism. 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 (however, see PRECAUTIONS below) 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 AND ADMINISTRATION Adult Dosage Dosage should be titrated to the needs of the individual patient. When used alone, the usual starting dose is 100 mg twice daily after meals. When combined with another diuretic or antihypertensive agent, the total daily dosage of each agent should usually be lowered initially and then adjusted to the patient’s needs. The total daily dosage should not exceed 300 mg. Please refer to PRECAUTIONS−General. When Dyrenium (triamterene) is added to other diuretic therapy or when patients are switched to Dyrenium from other diuretics, all potassium supplementation should be discontinued.

CONTRAINDICATIONS 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. WARNINGS 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.

ADVERSE REACTIONS 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. To report SUSPECTED ADVERSE REACTIONS, contact Advanz Pharma (US) Corp. at 1-877-370-1142 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions 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.

DESCRIPTION Each capsule for oral use, with opaque red cap and body, contains Triamterene USP, 50 or 100 mg, and is imprinted with the product name, DYRENIUM, strength (50 mg or 100 mg) and WPC 002 (for the 50-mg strength) and WPC 003 (for the 100-mg strength). Inactive ingredients consist of D&C Red No. 33, FD&C Yellow No. 6, Gelatin NF, Lactose NF, Magnesium Stearate NF, and Titanium Dioxide USP. Triamterene is 2,4,7-triamino-6-phenyl-pteridine: Its molecular weight is 253.27. At 50°C, triamterene is slightly soluble in water. It is soluble in dilute ammonia, dilute aqueous sodium hydroxide and dimethylformamide. It is sparingly soluble in methanol. Triamterene Chemical Structure

OVERDOSAGE In the event of overdosage, it can be theorized that electrolyte imbalance would be the major concern, with particular attention to possible hyperkalemia. Other symptoms that might be seen would be nausea and vomiting,other G.I. disturbances and weakness. It is conceivable that some hypotension could occur. As with an overdose of any drug, immediate evacuation of the stomach should be induced through emesis and gastric lavage. Careful evaluation of the electrolyte pattern and fluid balance should be made. There is no specific antidote. Reversible acute renal failure following ingestion of 50 tablets of a product containing a combination of 50 mg triamterene and 25 mg hydrochlorothiazide has been reported. The oral LD50 in mice is 380 mg/kg. The amount of drug in a single dose ordinarily associated with symptoms of overdose or likely to be life-threatening is not known. Although triamterene is 67% protein bound, there may be some benefit to dialysis in cases of overdosage.

HOW SUPPLIED Capsules: 50 mg in bottles of 100, and 100 mg in bottles of 100.