triamterene / benzthiazide

Action and Spectrum

Actions and Spectrum: 

triamterene 

triamterene is a potassium-sparing diuretic. It prevents sodium ions’ reabsorption in the distal renal tubules of the kidneys. By doing so, it promotes the excretion of sodium while retaining potassium ions. This ultimately leads to increased sodium and water excretion, which helps reduce fluid retention and lower blood pressure. 

benzthiazide 

benzthiazide is a thiazide diuretic. It acts on the early segment of the distal convoluted tubules in the kidneys by inhibiting the reabsorption of sodium and chloride ions. This increases the excretion of sodium, chloride, and water from the body, ultimately reducing blood volume and lowering blood pressure. 

Drug Interaction

Adverse Reaction

Frequency not defined  

Dry mouth 

Tingling fingers 

Confusion 

Blurred vision 

Dizziness 

Hyponatremia 

Hyper-kalemia 

Weakness 

Black Box Warning

Black Box Warning:  

None

Contraindication / Caution

Contraindication/Caution:  

Hypersensitivity: Individuals with a known hypersensitivity or allergy to triamterene, benzthiazide, or any of the inactive ingredients in the medication should not take it. 

Anuria: triamterene/benzthiazide is contraindicated in patients with anuria, which is the absence of urine production. The medication may further decrease urine output, leading to serious complications. 

Severe renal impairment: Individuals with severe kidney dysfunction or renal failure should not use triamterene/benzthiazide, as it can exacerbate electrolyte imbalances and other kidney-related issues. 

Hyperkalemia: triamterene/benzthiazide can increase serum potassium levels. It is contraindicated in patients with hyperkalemia (high levels of potassium in the blood) or conditions predisposing them to hyperkalemia, such as chronic kidney disease. 

Concurrent use of potassium-sparing diuretics: triamterene/benzthiazide with other potassium-sparing diuretics, such as spironolactone or amiloride, can lead to excessive potassium retention and hyperkalemia. This combination is generally contraindicated. 

Severe liver disease: Individuals with severe liver impairment should avoid triamterene/benzthiazide, as liver dysfunction can potentially affect the way medication is metabolized and eliminated from the body. 

Pregnancy / Lactation

Pregnancy warnings:     

Pregnancy category: N/A 

Lactation: Excreted into human milk is unknown 

Pregnancy Categories:         

Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester. 

Category B: There were a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.   

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.   

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology:  

triamterene belongs to a class of drugs known as potassium-sparing diuretics. benzthiazide is a thiazide diuretics. 

Pharmacodynamics:  

triamterene 

triamterene demonstrates its diuretic action by blocking sodium channels (ENaC) within the distal convoluted tubules and collecting ducts of the nephron located in the kidney. This inhibition reduces sodium reabsorption and, subsequently, decreases water reabsorption. Unlike other diuretics, triamterene does not significantly affect potassium excretion, it is classifying as a potassium-sparing diuretic. 

benzthiazide 

Thiazide diuretics like benzthiazide primarily act on the early distal convoluted tubules of the nephron in the kidney. They inhibit the sodium-chloride symporter, also known as the NCC (sodium-chloride cotransporter), leading to increased sodium and water excretion. This results in diuresis, a reduction in blood volume, and a decrease in blood pressure. 

Pharmacokinetics: 

Absorption 

triamterene is rapidly absorbed from the gastrointestinal tract after oral administration.  

benzthiazide is also well absorbed from the gastrointestinal tract after oral ingestion, and its absorption is influenced by food to some extent. 

Distribution 

triamterene is distributed throughout the body, with a moderate volume of distribution. It does not extensively bind to plasma proteins, allowing it to distribute into tissues. 

benzthiazide also has a moderate volume of distribution and is distributed throughout the body tissues. It does not have strong protein-binding properties. 

Metabolism 

triamterene undergoes minimal hepatic metabolism. Its primary mode of elimination is through the urine without undergoing any significant alteration. 

benzthiazide is metabolized in the liver to some extent, with the formation of active metabolites. 

Excretion and Elimination 

The kidneys primarily excrete triamterene. It undergoes both glomerular filtration and tubular secretion. A significant portion of the medication is eliminated in its original form through urinary excretion. 

benzthiazide is primarily excreted in the urine, with a portion excreted unchanged. The active metabolites of benzthiazide are also excreted in the urine. 

Adminstartion

Administration:  

The dosing of triamterene/benzthiazide may differ based on your specific medical condition and the extent of your symptoms. You can take triamterene/benzthiazide with or without food, but it’s essential to take it consistently at the same time each day to help you remember and maintain steady drug levels in your body. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: triamterene/benzthiazide 

Why do we use triamterene/benzthiazide?  

triamterene/benzthiazide aids in reducing blood pressure by enhancing the elimination of sodium and water from the system, thereby reducing blood volume and pressure against the blood vessel walls. 

This combination of medication reduces edema, edema is the accumulation of excess fluid within the body’s tissues. Boosting urine production and eliminating extra sodium and water reduces symptoms like swelling and bloating.