triamterene

Absorption: 30–70% absorbed.

Distribution: Widely distributed.

Metabolism/Excretion: 80% metabolized by the liver, some excretion of unchanged drug.

Half-Life: 1.7–2.5 hr.

Time/Action Profile ⬆ ⬇

(diuretic effect)

ROUTE	ONSET	PEAK	DURATION
	2–4 hr‡	1–several days‡	7–9 hr‡

‡Single dose.

‡Multiple doses.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Hyperkalemia;
Concurrent use of potassium supplements or other potassium-sparing agents;
Lactation: Lactation.

Use Cautiously in:

Hepatic dysfunction;
Patients with diabetes mellitus (increased risk of hyperkalemia);
Renal insufficiency;
History of gout or kidney stones;
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: arrhythmias

Derm: photosensitivity

F and E: hyperkalemia, hyponatremia

GI: nausea, vomiting

GU: bluish urine, erectile dysfunction, nephrolithiasis

Hemat: blood dyscrasias

MS: muscle cramps

Neuro: dizziness

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS)

Interactions ⬆ ⬇

Drug-drug:

↑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 ⬆ ⬇

PO (Adults ): 100 mg twice daily; may titrate based on level of diuresis (max dose = 300 mg/day).

Availability ⬆ ⬇

(Generic available)

Capsules: 50 mg; 100 mg
In combination with: hydrochlorothiazide (Maxzide). See Appendix [not included in this PDA edition].

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.
Monitor ECGs periodically in patients receiving prolonged therapy.

Lab Test Considerations:

Evaluate serum potassium levels prior to and routinely during therapy. Withhold drug and notify 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.

Implementation ⬆ ⬇

PO: 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, NSAIDs, cough or cold preparations, or appetite suppressants concurrently with this medication; may 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.
- Advise females to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
- 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.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇