Pharmacology of Triamterene/Hydrochlorothiazide

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Questions and Answers

What is the brand name of Triamterene/Hydrochlorothiazide?

HCTZ

Dyazide (correct)

Maxzide (correct)

Lasix

What is the drug class of Triamterene/Hydrochlorothiazide?

Potassium Sparing/Thiazide Diuretic Combination

What is the dosing for Triamterene/Hydrochlorothiazide?

Edema: 37.5 mg/25 mg, 1-2 tablets or capsules po daily; Hypertension: 37.5 mg/25 mg, 1 tablet or capsule po daily, may titrate to 75 mg/50 mg po daily

What is the MOA of Triamterene/Hydrochlorothiazide?

Triamterene acts from the distal tubular lumen on sodium exchange for potassium and hydrogen; Hydrochlorothiazide increases sodium and chloride excretion. Signup and view all the answers

Is there a dose adjustment required for renal function in Triamterene/Hydrochlorothiazide?

True Signup and view all the answers

Are there pharmacogenetics for Triamterene/Hydrochlorothiazide?

False Signup and view all the answers

What are the contraindications for Triamterene/Hydrochlorothiazide?

Hypersensitivity to hydrochlorothiazide, sulfonamides, or triamterene; concomitant use of potassium supplements; anuria, acute/chronic renal insufficiency, or hyperkalemia. Signup and view all the answers

What are the boxed warnings for Triamterene/Hydrochlorothiazide?

Hyperkalemia, increased skin cancer risk Signup and view all the answers

What are the drug interactions with Triamterene/Hydrochlorothiazide?

Aliskiren, ACE-Is, angiotensin-receptor blockers, potassium-sparing diuretics, eplerenone, potassium supplements, salt substitutes, calcium supplements, antidiabetic medications, NSAIDs. Signup and view all the answers

What are common adverse reactions to Triamterene/Hydrochlorothiazide?

Hypotension, dizziness, headache Signup and view all the answers

What are rare but serious adverse reactions to Triamterene/Hydrochlorothiazide?

Cardiac arrhythmias, hepatitis, hyperkalemia, gout, pancreatitis, Stevens-Johnson syndrome, decreased visual acuity Signup and view all the answers

What are the efficacy monitoring parameters for Triamterene/Hydrochlorothiazide?

Decreased BP, reductions in edema Signup and view all the answers

What are the toxicity monitoring parameters for Triamterene/Hydrochlorothiazide?

Altered serum and urine electrolytes, decreased renal function, increased serum uric acid or blood glucose. Signup and view all the answers

Study Notes

Brand Names

Triamterene/Hydrochlorothiazide is marketed as Dyazide and Maxzide.

Drug Classification

It belongs to the Potassium Sparing/Thiazide Diuretic Combination class.

Dosing Information

For Edema: Administer 37.5 mg/25 mg, 1-2 tablets/capsules once daily.
For Hypertension: Start with 37.5 mg/25 mg, 1 tablet/capsule once daily; titrate to a maximum of 75 mg/50 mg as needed.

Mechanism of Action

Triamterene works in the distal tubular lumen, impacting sodium exchange for potassium and hydrogen, leading to a mild diuresis independent of aldosterone.
Hydrochlorothiazide increases sodium and chloride excretion by hindering reabsorption in the nephron, resulting in urine that is mildly concentrated.

Renal Dose Adjustment

Renal dose adjustments are necessary for this medication.

Pharmacogenetics

There are no known pharmacogenetic considerations for this drug combination.

Contraindications

Contraindicated in patients with hypersensitivity to hydrochlorothiazide, sulfonamides, or triamterene.
Avoid use with potassium supplements, potassium-containing salt substitutes, other potassium-sparing diuretics, or in patients with anuria, renal insufficiency, or hyperkalemia.

Boxed Warnings

Notable risks include hyperkalemia and an increased risk of skin cancer.

Drug Interactions

Interactions may occur with Aliskiren, ACE inhibitors, angiotensin-receptor blockers, other potassium-sparing diuretics, Eplerenone, potassium supplements, salt substitutes, calcium supplements, antidiabetic medications, and NSAIDs.

Common Adverse Reactions

Side effects often include hypotension, dizziness, and headache.

Rare but Serious Adverse Reactions

Serious side effects can involve cardiac arrhythmias, hepatitis, hyperkalemia, gout, pancreatitis, Stevens-Johnson syndrome, and decreased visual acuity.

Efficacy Monitoring Parameters

Monitor for decreased blood pressure and reductions in edema as indicators of efficacy.

Toxicity Monitoring Parameters

Regularly check serum and urine electrolytes (calcium, magnesium, potassium, sodium) and renal function (creatinine levels and urine output).
Look for increased serum uric acid or blood glucose levels, and seek medical help for skin rash, jaundice, decreased urine output, or gout symptoms.

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Description

This quiz covers the pharmacology of the potassium-sparing and thiazide diuretic combination, Triamterene/Hydrochlorothiazide. It includes brand names, dosing information, mechanisms of action, renal dose adjustments, and contraindications. Test your understanding of this medication's therapeutic uses and pharmacokinetics.