Triamterene

Contraindications

Hypersensitivity to triamterene

Anuria, severe liver disease, renal failure

Hyperkalemia

Concomitant use with K+-sparing diuretic, or K supplementation

Cautions

Acid-base imbalance, electrolyte abnormalities, hyperuricemia or gout, liver dz, renal impairment, renal stones

Breastfeeding

Interferes with fluorescent assay of quinidine

Not recommended for pregnancy-induced HTN

Use during pregnancy may increase risk of cardiovascular defects and oral cleft in child

Keep this medicine in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

• Dyrenium^®

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.

Serious side effects have been reported with triamterene. See “Drug Precautions” section.

Common side effects of triamterene include:

• vomiting
• headache
• dizziness

This is not a complete list of triamterene side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Before taking triamterene, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to triamterene or any other medications
• are taking amiloride (Midamor), spironolactone (Aldactone), or other medications containing triamterene
• have or have ever had diabetes, gout, kidney stones, or heart, kidney, or liver disease.
• are pregnant or plan to become pregnant. If you become pregnant while taking triamterene, call your doctor. Do not breastfeed if you are taking triamterene.
• are having surgery, including dental surgery, tell the doctor or dentist that you are taking triamterene.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Triamterene falls into category C. This medication may be given to a pregnant woman if her healthcare provider believes that its benefits to the pregnant woman outweigh any possible risks to her unborn baby.

It is not known if triamterene will harm your unborn baby.

Absorption

Bioavailability

Triamterene and fixed combinations with hydrochlorothiazide are rapidly absorbed following oral administration;c d peak plasma concentrations achieved within 1–4 hours.a b d Interindividual variation in degree of absorption reported.a

Oral bioavailabilities of triamterene and hydrochlorothiazide from Dyazide capsules are comparable to those of aqueous suspensions of the individual drugs, averaging 85 and 82%, respectively, for the fixed-dose formulation and 100 and 100%, respectively, for the suspensions.111 Dyazide capsules also are bioequivalent to single-entity 25-mg hydrochlorothiazide tablets and 37.5-mg triamterene capsules.110

Oral bioavailabilities of triamterene and hydrochlorothiazide from Maxzide tablets are comparable to those of aqueous suspensions of the individual drugs.d The hydrochlorothiazide component of Maxzide tablets is bioequivalent to single-entity hydrochlorothiazide tablet formulations.d

Onset

Onset of diuresis following oral administration of triamterene usually occurs within 2–4 hours; maximum therapeutic effect may not occur until after several days of therapy.b

Onset of diuresis after oral administration of Dyazide usually occurs within 1 hour and peaks at 2–3 hours.c

Duration

After oral administration of triamterene, diuresis diminishes in approximately 7–9 hours,a b although the total duration of action may be ≥24 hours.a

After oral administration of Dyazide, diuresis diminishes in approximately 7–9 hours.c

Food

Administration of Dyazide with a high-fat meal in healthy adults increased the average bioavailabilities of triamterene, 6-p-hydroxytriamterene, and hydrochlorothiazide by about 67, 50, and 17%, respectively; increased the peak concentrations of triamterene and its p-hydroxy metabolite; and delayed absorption of the active drugs by up to 2 hours.110

Administration with food does not affect absorption of triamterene or hydrochlorothiazide from Maxzide tablets.d

Distribution

Extent

Distributed into bile.a

Crosses the placenta and distributes into milk in animals.b

Plasma Protein Binding

Approximately 67%.b

Elimination

Metabolism

Primarily metabolized to 6-p-hydroxytriamterene and its sulfate conjugate.b 107

Elimination Route

Excreted in urine, primarily as 6-p-hydroxytriamterene.b

Half-life

100–150 minutes.a

Special Populations

Renal clearances of triamterene, hydroxytriamterene sulfate, and hydrochlorothiazide may be reduced in geriatric patients receiving combined triamterene and hydrochlorothiazide therapy, principally as a result of age-related reductions in renal function.107 a

Storage

Oral

Tight, light resistant containers at 15–30°C.a b

Dyazide capsules: Tight, light resistant containers at 20–25°C.c

Maxzide tablets: Tight, light resistant containers at 15–30°C.d

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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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.

Absorption

Rapid

Metabolism

Primarily metabolized to the sulfate conjugate of hydroxytriamterene

Excretion

Urine (21% to <50%; primarily as metabolites)

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; preexisting 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; coadministration with other potassium-sparing agents, such as spironolactone, amiloride, or other formulations containing triamterene

ACE Inhibitors: Potassium-Sparing Diuretics may enhance the hyperkalemic effect of ACE Inhibitors. Monitor therapy

Alfuzosin: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, blood pressure lowering medications should be withheld for 24 hours prior to amifostine administration. If blood pressure lowering therapy cannot be withheld, amifostine should not be administered. Consider therapy modification

Ammonium Chloride: Potassium-Sparing Diuretics may enhance the adverse/toxic effect of Ammonium Chloride. Specifically the risk of systemic acidosis. Consider therapy modification

Amphetamines: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Analgesics (Opioid): May enhance the adverse/toxic effect of Diuretics. Analgesics (Opioid) may diminish the therapeutic effect of Diuretics. Monitor therapy

Angiotensin II Receptor Blockers: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Monitor therapy

Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Monitor therapy

Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Brigatinib: May diminish the antihypertensive effect of Antihypertensive Agents. Brigatinib may enhance the bradycardic effect of Antihypertensive Agents. Monitor therapy

Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Canagliflozin: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Canagliflozin may enhance the hypotensive effect of Potassium-Sparing Diuretics. 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. Monitor therapy

CycloSPORINE (Systemic): Potassium-Sparing Diuretics may enhance the hyperkalemic effect of CycloSPORINE (Systemic). Avoid combination

Diacerein: May enhance the therapeutic effect of Diuretics. Specifically, the risk for dehydration or hypokalemia may be increased. Monitor therapy

Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Dofetilide: Triamterene may increase the serum concentration of Dofetilide. Monitor therapy

Drospirenone: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Monitor therapy

DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. 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. Consider therapy modification

Heparin: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Management: Monitor serum potassium concentrations closely. The spironolactone Canadian product monograph lists its combination with heparin or low molecular weight heparins as contraindicated. Monitor therapy

Heparin (Low Molecular Weight): May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Management: Monitor serum potassium concentrations closely. The spironolactone Canadian product monograph lists its combination with heparin or low molecular weight heparins as contraindicated. Monitor therapy

Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Herbs (Hypotensive Properties): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. 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. Consider therapy modification

Levodopa: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa. Monitor therapy

Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Methylphenidate: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Naftopidil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicergoline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicorandil: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Monitor therapy

Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. 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. Monitor therapy

Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Consider therapy modification

Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Monitor therapy

Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Potassium Salts: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Consider therapy modification

Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

QuiNIDine: Potassium-Sparing Diuretics may diminish the therapeutic effect of QuiNIDine. Monitor therapy

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. Consider therapy modification

Spironolactone: Triamterene may enhance the hyperkalemic effect of Spironolactone. Avoid combination

Tacrolimus (Systemic): Potassium-Sparing Diuretics may enhance the hyperkalemic effect of Tacrolimus (Systemic). Avoid combination

Tolvaptan: May enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Monitor therapy

Yohimbine: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Tell your doctor about all your current medicines and any you start or stop using, especially:

• any other diuretic;

• chlorpropamide;

• lithium;

• heart or blood pressure medicine; or

• NSAIDs (nonsteroidal anti-inflammatory drugs) - aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others.

This list is not complete. Other drugs may interact with triamterene, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Applies to triamterene: compounding powder, oral capsule

Gastrointestinal

Uncommon (0.1% to 1%): Rash
Rare (less than 0.1%): Photosensitivity reactions, pseudoporphyria[Ref]

Cardiovascular

Uncommon (0.1% to 1%): Hypovolemia[Ref]

Genitourinary

Frequency not reported: Blue fluorescence of the urine under certain light conditions[Ref]

Hematologic

Rare (less than 0.1%): Thrombocytopenia, megaloblastic anemia, pancytopenia[Ref]

Hepatic

Rare (less than 0.1%): Jaundice and/or liver enzyme abnormalities[Ref]

Hypersensitivity

Rare (less than 0.1%): Anaphylaxis, photosensitivity[Ref]

Metabolic

Very common (10% or more): Hyperkalemia
Uncommon (0.1% to 1%): Hyperuricemia
Rare (less than 0.1%): Hypokalemia, metabolic acidosis[Ref]

Nervous system

Uncommon (0.1% to 1%): Headache
Rare (less than 0.1%): Dizziness[Ref]

Other

Rare (less than 0.1%): Weakness, fatigue, serum sickness[Ref]

Renal

Uncommon (0.1% to 1%): Elevation of serum creatinine, transient renal insufficiency
Rare (0.01% to 0.1%): Interstitial nephritis, urinary stones, azotemia, elevated BUN and creatinine, renal stones, acute interstitial nephritis
Very rare (less than 0.01%): Renal failure[Ref]

Some side effects of triamterene may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Initial dose: 100 mg orally 2 times a day after meals
Maximum dose: 300 mg/day

Comments:
-The dosage should be titrated to the needs of the individual patient.
-The maximum therapeutic effect may not be seen for several days.
-When this drug is used concomitantly with another diuretic or antihypertensive agent, the total daily dose of each agent should be lowered initially and then adjusted according to patient need.

Use: To reduce edema in cardiac failure, cirrhosis of the liver or nephrotic syndrome, and in that associated with corticosteroid treatment

Triamterene is a potassium-sparing diuretic (water pill) that prevents your body from absorbing too much salt and keeps your potassium levels from getting too low.

Triamterene is used to treat fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, or a kidney condition called nephrotic syndrome.

Triamterene is also used to treat edema caused by using steroid medicine or having too much aldosterone in your body. Aldosterone is a hormone produced by the adrenal glands to help regulate the salt and water balance in your body.

Triamterene may also be used for purposes not listed in this medication guide.