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ALERT: U.S. Boxed Warning
The FDA-approved labeling includes a boxed warning. See Warnings/Precautions section for a concise summary of this information. For verbatim wording of the boxed warning, consult the product labeling or www.fda.gov.
Pronunciation
(trye AM ter een)
Generic Available (U.S.)
No
Brand Names: U.S.
Pharmacologic Category
Pharmacologic Category Synonyms
Use: Labeled Indications
Alone or in combination with other diuretics in treatment of edema and hypertension; decreases potassium excretion caused by kaliuretic diuretics
Pregnancy Risk Factor
C
Pregnancy Considerations
No data available. Generally, use of diuretics during pregnancy is avoided due to risk of decreased placental perfusion.
Lactation
Excretion in breast milk unknown
Breast-Feeding Considerations
No data available.
Contraindications
Hypersensitivity to triamterene or any component of the formulation; patients receiving other potassium-sparing diuretics; anuria; severe hepatic disease; hyperkalemia or history of hyperkalemia; severe or progressive renal disease; pregnancy (expert analysis)
Warnings/Precautions
Boxed warnings:
• Hyperkalemia: See “Concerns related to adverse effects” below.
Concerns related to adverse effects:
• Fluid/electrolyte loss: Excess amounts can lead to profound diuresis with fluid and electrolyte loss; close medical supervision and dose evaluation are required. Watch for and correct electrolyte disturbances; adjust dose to avoid dehydration.
• Hyperkalemia: [U.S. Boxed Warning]: Hyperkalemia can occur; patients at risk include those with renal impairment, diabetes, the elderly, and the severely ill. Serum potassium levels must be monitored at frequent intervals especially when dosages are changed or with any illness that may cause renal dysfunction.
• Photosensitivity: Can cause photosensitivity.
Disease-related concerns:
• Diabetes: Use with caution in patients with prediabetes or diabetes mellitus; may see a change in glucose control.
• Hepatic impairment: Use with caution in patients with severe hepatic dysfunction; in cirrhosis, avoid electrolyte and acid/base imbalances that might lead to hepatic encephalopathy.
• Kidney stones: Use with caution in patients with kidney stones.
Concurrent drug therapy issues:
• Potassium supplements: Avoid potassium supplements, potassium-containing salt substitutes, a diet rich in potassium, or other drugs that can cause hyperkalemia.
Adverse Reactions
1% to 10%:
Cardiovascular: Hypotension, edema, CHF, bradycardia
Central nervous system: Dizziness, headache, fatigue
Gastrointestinal: Constipation, nausea
Respiratory: Dyspnea
<1% (Limited to important or life-threatening): Inability to achieve or maintain an erection, agranulocytosis, thrombocytopenia
Metabolism/Transport Effects
None known.
Drug Interactions
ACE Inhibitors: Potassium-Sparing Diuretics may enhance the hyperkalemic effect of ACE Inhibitors. Risk C: Monitor therapy
Alfuzosin: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Amifostine: Antihypertensives may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, antihypertensive medications should be withheld for 24 hours prior to amifostine administration. If antihypertensive therapy can not be withheld, amifostine should not be administered. Risk D: Consider therapy modification
Ammonium Chloride: Potassium-Sparing Diuretics may enhance the adverse/toxic effect of Ammonium Chloride. Specifically the risk of systemic acidosis. Risk D: Consider therapy modification
Angiotensin II Receptor Blockers: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Risk C: Monitor therapy
Antihypertensives: May enhance the hypotensive effect of other Antihypertensives. Risk C: Monitor therapy
Cardiac Glycosides: Potassium-Sparing Diuretics may diminish the therapeutic effect of Cardiac Glycosides. In particular, the inotropic effects of digoxin appear to be diminished. Potassium-Sparing Diuretics may increase the serum concentration of Cardiac Glycosides. This particular effect may be unique to Spironolactone. Risk C: Monitor therapy
CycloSPORINE: Potassium-Sparing Diuretics may enhance the hyperkalemic effect of CycloSPORINE. Risk X: Avoid combination
CycloSPORINE (Systemic): Potassium-Sparing Diuretics may enhance the hyperkalemic effect of CycloSPORINE (Systemic). Risk X: Avoid combination
Diazoxide: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Dofetilide: Triamterene may increase the serum concentration of Dofetilide. Risk C: Monitor therapy
Drospirenone: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Risk C: Monitor therapy
Eplerenone: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Management: This combination is contraindicated in patients receiving eplerenone for treatment of hypertension. Risk D: Consider therapy modification
Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy
Herbs (Hypotensive Properties): May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Hypotensive Agents: May enhance the adverse/toxic effect of other Hypotensive Agents. Risk C: Monitor therapy
Indomethacin: May enhance the nephrotoxic effect of Triamterene. Management: Consider alternatives to concomitant treatment with triamterene and indomethacin. If the combination cannot be avoided, monitor for development of renal failure. Risk D: Consider therapy modification
MAO Inhibitors: May enhance the orthostatic hypotensive effect of Orthostatic Hypotension Producing Agents. Risk C: Monitor therapy
Methylphenidate: May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy
Nonsteroidal Anti-Inflammatory Agents: May diminish the antihypertensive effect of Potassium-Sparing Diuretics. Nonsteroidal Anti-Inflammatory Agents may enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Risk C: Monitor therapy
Pentoxifylline: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Phosphodiesterase 5 Inhibitors: May enhance the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy
Potassium Salts: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Risk D: Consider therapy modification
Prostacyclin Analogues: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
QuiNIDine: Potassium-Sparing Diuretics may diminish the therapeutic effect of QuiNIDine. Risk C: Monitor therapy
RiTUXimab: Antihypertensives may enhance the hypotensive effect of RiTUXimab. Risk D: Consider therapy modification
Sodium Phosphates: Diuretics may enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with diuretics, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, hydrate adequately and monitor fluid and renal status. Risk D: Consider therapy modification
Tacrolimus: Potassium-Sparing Diuretics may enhance the hyperkalemic effect of Tacrolimus. Risk X: Avoid combination
Tacrolimus (Systemic): Potassium-Sparing Diuretics may enhance the hyperkalemic effect of Tacrolimus (Systemic). Risk X: Avoid combination
Tolvaptan: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Risk C: Monitor therapy
Yohimbine: May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy
Mechanism of Action
Blocks epithelial sodium channels in the late distal convoluted tubule (DCT) and collecting duct which inhibits sodium reabsorption from the lumen. This effectively reduces intracellular sodium, decreasing the function of Na+/K+ ATPase, leading to potassium retention and decreased calcium, magnesium, and hydrogen excretion. As sodium uptake capacity in the DCT/collecting duct is limited, the natriuretic, diuretic, and antihypertensive effects are generally considered weak.
Pharmacodynamics/Kinetics
Onset of action: Diuresis: 2-4 hours
Duration: 7-9 hours
Absorption: Unreliable
Dosage
Oral:
Children (unlabeled use): Hypertension: Initial: 1-2 mg/kg/day in 2 divided doses; maximum: 3-4 mg/kg/day, up to 300 mg/day
Adults: Hypertension, edema: 100-300 mg/day in 1-2 divided doses; maximum dose: 300 mg/day; usual dosage range (JNC 7): 50-100 mg/day
Elderly: Hypertension: Consider lower initial doses and titrate to response (Aronow, 2011)
Dosing comments in renal impairment: Clcr <10 mL/minute: Avoid use.
Dosing adjustment in hepatic impairment: Dose reduction is recommended in patients with cirrhosis.
Administration: Oral
May be administered with food.
Monitoring Parameters
Blood pressure; serum electrolytes (especially potassium), renal function; weight, I & O
Test Interactions
Interferes with fluorometric assay of quinidine
Dietary Considerations
May be taken with food.
Geriatric Considerations
Monitor serum potassium.
Anesthesia and Critical Care Concerns/Other Considerations
Abrupt discontinuation of therapy may result in rebound kaliuresis; taper off gradually. Triamterene may cause hyperkalemia particularly in diabetes mellitus and those patients with renal dysfunction.
Cardiovascular Considerations
Triamterene is usually combined with other antihypertensive agents for the treatment of hypertension. Triamterene may cause hyperkalemia, the ECG manifestations of which include peaked T waves, QRS prolongation, and cardiac conduction abnormalities.
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
May cause drowsiness or dizziness
Mental Health: Effects on Psychiatric Treatment
Triamterene may increase the side effects of amantadine (dizziness, nausea, dry mouth) necessitating a decrease in dosage; monitor
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, oral:
Dyrenium®: 50 mg, 100 mg
Pricing: U.S. (www.drugstore.com)
Capsules (Dyrenium)
50 mg (30): $49.99
100 mg (30): $75.99
References
Aronow WS, Fleg JL, Pepine CJ, et al, “ACCF/AHA 2011 Expert Consensus Document on Hypertension in the Elderly: A Report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents,” Circulation, 2011, 123(21):2434-506.
Chobanian AV, Bakris GL, Black HR, et al, “The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: The JNC 7 Report,” JAMA, 2003, 289(19):2560-71.
Lindenfeld J, Albert NM, Boehmer JP, et al, “HFSA 2010 Comprehensive Heart Failure Practice Guideline,” J Card Fail, 2010, 16(6):e1-194.
National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents, “The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents,” Pediatrics, 2004, 114(2 Suppl):555-76.
International Brand Names
Lexi-Comp.com
Last full review/revision December 2011
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