Dyrenium


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triamterene

Dyrenium, Dytac (UK)

Pharmacologic class: Potassium-sparing diuretic

Therapeutic class: Diuretic

Pregnancy risk category B

FDA Box Warning

• Abnormal serum potassium elevation may occur, and is more likely in patients with renal impairment or diabetes and in elderly or severely ill patients. As uncorrected hyperkalemia may be fatal, monitor serum potassium levels frequently, especially when dosage is changed or patient has an illness that may influence renal function.

Action

Depresses sodium resorption and potassium excretion in renal distal tubule

Availability

Capsules: 50 mg, 100 mg

Indications and dosages

Edema

Adults: 100 mg P.O. b.i.d. Do not exceed 300 mg/day.

Dosage adjustment

• Concurrent antihypertensive drug therapy

• Elderly patients

Off-label uses

• Diabetes insipidus

Contraindications

• Hypersensitivity to drug

• Hyperkalemia

• Severe hepatic disease

• Anuria, severe renal dysfunction (except nephrosis)

• Concurrent use of other potassium-sparing diuretics or potassium supplements

Precautions

Use cautiously in:

• hepatic dysfunction, renal insufficiency, diabetes mellitus

• history of gout or renal calculi

• elderly or debilitated patients

• pregnant or breastfeeding patients

• children (safety not established).

Administration

• Give after meals.

• Know that drug may be used alone or as adjunct to thiazide or loop diuretics.

• Make sure patient stops taking potassium supplements before starting triamterene.

Adverse reactions

CNS: headache, fatigue, asthenia, dizziness

GI: nausea, vomiting, diarrhea, dry mouth

GU: azotemia, renal calculi

Hematologic: megaloblastic anemia, thrombocytopenia

Hepatic: jaundice

Metabolic: hyperglycemia, hyperkalemia, metabolic acidosis

Skin: rash, photosensitivity

Other: anaphylaxis

Interactions

Drug-drug. Amantadine: increased amantadine blood level, greater risk of toxicity

Angiotensin-converting enzyme inhibitors, cyclosporine, indomethacin, potassium-sparing diuretics, potassium supplements, other potassium-containing

preparations: increased risk of hyperkalemia

Antihypertensives, nondepolarizing muscle relaxants, other diuretics, preanesthetic and anesthetic agents: potentiated effects of these drugs

Chlorpropamide: increased risk of hyponatremia

Cimetidine: increased bioavailability and decreased renal clearance of triamterene

Indomethacin: increased risk of acute renal failure

Lithium: decreased lithium clearance, greater risk of lithium toxicity

Drug-diagnostic tests. Alkali reserves, hemoglobin, platelets: decreased values

Blood urea nitrogen (BUN), creatinine, glucose, hepatic enzymes, potassium: increased levels

Liver function tests: increased values

Quinidine blood level: interference with fluorescent measurement

Drug-food. Salt substitutes containing potassium: increased risk of hyperkalemia

Drug-herbs. Gossypol, licorice: increased risk of hypokalemia

Patient monitoring

• Monitor BUN, creatinine, and electrolyte levels. Stay alert for hyperkalemia.

• Assess CBC with white cell differential.

Patient teaching

• Advise patient to take after meals to reduce nausea.

• Instruct patient to take last daily dose in early evening to avoid nocturia.

• Teach patient to recognize and report signs and symptoms of electrolyte imbalances.

• Tell patient to avoid salt substitutes. Advise him not to use herbs without consulting prescriber.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.

triamterene

(trye-am-ter-een) ,

Dyrenium

(trade name)

Classification

Therapeutic: diuretics
Pregnancy Category: C ()

Indications

Counteracts potassium loss caused by other diuretics.Used with other agents to treat edema or hypertension.

Action

Inhibition of sodium resorption in the kidney, while saving potassium and hydrogen ions.

Therapeutic effects

Weak diuretic and antihypertensive response when compared with other diuretics.
Conservation of potassium.

Pharmacokinetics

Absorption: 30–70% absorbed.
Distribution: Widely distributed.
Metabolism and Excretion: 80% metabolized by the liver, some excretion of unchanged drug.
Half-life: 1.7–2.5 hr.

Time/action profile (diuretic effect)

ROUTEONSETPEAKDURATION
2–4 hr†1–several days‡7–9 hr†
†Single dose‡Multiple doses

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Hyperkalemia; Concurrent use of potassium supplements or other potassium-sparing agents.
Use Cautiously in: Hepatic dysfunction; Patients with diabetes mellitus (increased risk of hyperkalemia); Renal insufficiency; History of gout or kidney stones; Pregnancy, lactation, or children (safety not established).

Adverse Reactions/Side Effects

Central nervous system

  • dizziness

Cardiovascular

  • arrhythmias

Gastrointestinal

  • nausea
  • vomiting

Genitourinary

  • erectile dysfunction
  • bluish urine
  • nephrolithiasis

Dermatologic

  • photosensitivity

Fluid and Electrolyte

  • hyperkalemia (most frequent)
  • hyponatremia

Hematologic

  • blood dyscrasias

Musculoskeletal

  • muscle cramps

Miscellaneous

  • allergic reactions

Interactions

Drug-Drug interaction

↑ hypotension with acute ingestion of alcohol, other antihypertensive agents, or nitrates.Use with ACE inhibitors,indomethacin,angiotensin II receptor antagonists potassium supplements, or cyclosporine ↑ risk of hyperkalemia.↓lithium excretion.Effectiveness may be ↓ by NSAIDs.↓ the effects of folic acid (leucovorin should be used).May ↑ risk of toxicity from amantadine.

Route/Dosage

Oral (Adults) 25–100 mg/day (not to exceed 300 mg/day).
Oral (Children) 2–4 mg/kg/day (120 mg/m2/day) in divided doses given daily or every other day (not to exceed 6 mg/kg/day or 300 mg/day).

Availability

Capsules: 50 mg, 100 mg
Tablets: 50 mg, 100 mg
In combination with: hydrochlorothiazide (Apo-Triazide, Dyazide, Maxzide, {Novo-Triamzide}). See combination drugs.

Nursing implications

Nursing assessment

  • Monitor intake and output ratios and daily weight during therapy.
  • If medication is given as an adjunct to antihypertensive therapy, BP should be evaluated before administering.
  • Monitor response of signs and symptoms of hypokalemia (weakness, fatigue, ECG changes, arrhythmias, polyuria, polydipsia). Assess patient frequently for development of hyperkalemia (fatigue, muscle weakness, paresthesia, confusion, dyspnea, cardiac arrhythmias). Patients who have diabetes mellitus or kidney disease and elderly patients are at increased risk of developing these symptoms.
  • Periodic ECGs may be considered in patients receiving prolonged therapy.
  • Lab Test Considerations: Evaluate serum potassium levels prior to and routinely during therapy. Withhold drug and notify physician or other health care professional if patient becomes hyperkalemic.
    • Monitor BUN, serum creatinine, and electrolytes prior to and periodically during therapy. May cause ↑ serum magnesium, uric acid, BUN, creatinine, potassium, and urinary calcium excretion levels. May also cause ↓ sodium levels.
    • Discontinue potassium-sparing diuretics 3 days prior to a glucose tolerance test because of risk of severe hyperkalemia.
    • Monitor platelet count and total and differential leukocyte count prior to and periodically during therapy in patients taking triamterene.

Potential Nursing Diagnoses

Excess fluid volume (Indications)

Implementation

  • Oral: Administer in am to avoid interrupting sleep pattern for urination.
    • Triamterene capsules may be opened and contents mixed with food or fluids for patients with difficulty swallowing.

Patient/Family Teaching

  • Emphasize the importance of continuing to take this medication, even if feeling well. Instruct patient to take medication at the same time each day. Take missed doses as soon as remembered unless almost time for next dose. Do not double doses.
    • Caution patient to avoid salt substitutes and foods that contain high levels of potassium or sodium unless prescribed by health care professional.
    • May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
    • Advise patient to consult with health care professional before taking any OTC or herbal decongestants, cough or cold preparations, or appetite suppressants concurrently with this medication because of potential for increased BP.
    • Advise patients taking triamterene to use sunscreen and protective clothing to prevent photosensitivity reactions.
    • Instruct patient to notify health care professional of medication regimen prior to treatment or surgery.
    • Inform patient that triamterene may cause bluish-colored urine.
    • Advise patient to notify health care professional if muscle weakness or cramps; fatigue; or severe nausea, vomiting, or diarrhea occurs.
    • Emphasize the need for follow-up exams to monitor progress.
  • Hypertension: Reinforce need to continue additional therapies for hypertension (weight loss, restricted sodium intake, stress reduction, moderation of alcohol intake, regular exercise, and cessation of smoking). Medication helps control but does not cure hypertension.
    • Teach patient and family the correct technique for checking BP weekly.

Evaluation/Desired Outcomes

  • Increase in diuresis and decrease in edema while maintaining appropriate serum potassium level.
  • Decrease in BP.
  • Prevention of hypokalemia in patients taking diuretics.

Dyrenium

a trademark for a potassium-sparing diuretic (triamterene).
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