Triamteren

Triamteren Uses, Dosage, Side Effects, Food Interaction and all others data.

Triamteren (2,4,7-triamino-6-phenylpteridine) is a potassium-sparing diuretic that is used in the management of hypertension. It works by promoting the excretion of sodium ions and water while decreasing the potassium excretion in the distal part of the nephron in the kidneys by working on the lumenal side. Since it acts on the distal nephron where only a small fraction of sodium ion reabsorption occurs, triamterene is reported to have limited diuretic efficacy. Due to its effects on increased serum potassium levels, triamterene is associated with a risk of producing hyperkalemia. Triamteren is a weak antagonist of folic acid, and a photosensitizing drug.

Triamteren was approved by the Food and Drug Administration in the U.S. in 1964. Currently, triamterene is used in the treatment of edema associated with various conditions as monotherapy and is approved for use with other diuretics to enhance diuretic and potassium-sparing effects. It is also found in a combination product with hydrochlorothiazide that is used for the management of hypertension or treatment of edema in patients who develop hypokalemia on hydrochlorothiazide alone.

Triamteren, a relatively weak, potassium-sparing diuretic and antihypertensive, is used in the management of hypertension and edema. It primarily works on the distal nephron in the kidneys; it acts from the late distal tubule to the collecting duct to inhibit Na+ reabsorption and decreasing K+ excretion. As triamterene tends to conserve potassium more strongly than promoting Na+ excretion, it can cause an increase in serum potassium, which may result in hyperkalemia potentially associated with cardiac irregularities. In healthy volunteers administered with oral triamterene, there was an increase in the renal clearnace of sodium and magnesium, and a decrease in the clearance of uric acid and creatinine due to its effect of reducing glomerular filtration renal plasma flow. Triamteren does not affect calcium excretion. In clinical trials, the use of triamterene in combination with hydrochlorothiazide resulted an enhanced blood pressure-lowering effects of hydrochlorothiazide.

Trade Name Triamteren
Availability Prescription only
Generic Triamterene
Triamterene Other Names Teridin, Triamteren, Triamterena, Triamtérène, Triamterene, Triamtereno, Triamterenum
Related Drugs furosemide, hydrochlorothiazide, spironolactone, Lasix, chlorthalidone, torsemide, bumetanide, Bumex, amiloride
Type
Formula C12H11N7
Weight Average: 253.2626
Monoisotopic: 253.107593387
Protein binding

67% bound to proteins.

Groups Approved
Therapeutic Class
Manufacturer
Available Country
Last Updated: September 19, 2023 at 7:00 am
Triamteren
Triamteren

Uses

Triamteren is a potassium-sparing diuretic used in the treatment of edema and in the management of hypertension.

Triamteren is indicated for the treatment of edema associated with congestive heart failure, cirrhosis of the liver, and the nephrotic syndrome; also in steroid-induced edema, idiopathic edema, and edema due to secondary hyperaldosteronism.

Triamteren in combination with hydrochlorothiazide is indicated for the managment of hypertension or treatment of edema in patients who develop hypokalemia following hydrochlorothiazide monotherapy, and in patients who require thiazide diuretic and in whom the development of hypokalemia cannot be risked. Triamteren allows the maintenance of potassium balance when given in combination with loop diuretics and thiazides.

Triamteren is also used to associated treatment for these conditions: Edema, High Blood Pressure (Hypertension), Idiopathic Edema

How Triamteren works

Triamteren inhibits the epithelial sodium channels (ENaC) located on the lumenal side in the late distal convoluted tubule and collecting tubule , which are transmembrane channels that normally promotes sodium uptake and potassium secretion. In the late distal tubule to the collecting duct, sodium ions are actively reabsorbed via ENaC on the lumnial membrane and are extruded out of the cell into the peritubular medium by a sodium-potassium exchange pump, the Na-K-ATPase, with water following passively. Triamteren exerts a diuretic effect on the distal renal tubule to inhibit the reabsorption of sodium ions in exchange for potassium and hydrogen ions and its natriuretic activity is limited by the amount of sodium reaching its site of action. Its action is antagonistic to that of adrenal mineralocorticoids, such as aldosterone, but it is not an inhibitor or antagonist of aldosterone. Triamteren maintains or increases the sodium excretionm, thereby increasing the excretion of water, and reduces the excess loss of potassium, hydrogen and chloride ions by inhibiting the distal tubular exchange mechanism. Due to its diuretic effect, triamterene rapidly and reversibly reduces the lumen-negative transepithelial potential difference by almost complete abolition of Na+ conductance without altering K+ conductance. This reduces the driving force for potassium movement into the tubular lumen and thus decreases potassium excretion. Triamteren is similar in action to amiloride but, unlike amiloride, increases the urinary excretion of magnesium.

Toxicity

Acute oral LD50 of triamterene in rats is 400 mg/kg and 285-380 mg/kg in mice. There has been a case of reversible acute renal failure following ingestion of 50 combination pills containing 50 mg triamterene and 25 mg hydrochlorothiazide. Symptoms of overdose, such as nausea, vomiting, gastrointestinal disturbances, weakness, and hypotension, are related to electrolyte imbalances, such as hyperkalemia. As there is no specific antidote, emesis and gastric lavage should be use to induce immediate evacuation of the stomach and careful evaluation of the electrolyte pattern and fluid balance should be made. Dialysis may be somewhat effective in case of an overdosage.

In a carciongenicity study in male and female mice administered with triamterene at the highst dosage level, there was an increased incidence of hepatocellular neoplasia, primarily adenomas. However, this was not a dose-dependent phenomenon and there was no statistically significant difference from control incidence at any dose level. In bacterial assays, there was no demonstrated mutagenic potential of triamterene. In in vitro assay using Chinese hamster ovary (CHO) cells with or without metabolic activation, there were no chromosomal aberrations. Studies evaluating the effects of triamterene on reproductive system or fertility have not been conducted. It is advised that the use of triamterene is avoided during pregnancy. As triamterene has been detected in human breast milk, triamterene should be used when nursing is ceased.

Food Interaction

  • Avoid potassium-containing products. The risk of hyperkalemia can be increased with the intake of potassium supplementation or potassium-rich foods.

Triamteren Alcohol interaction

[Moderate]

Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation.

Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

Caution and close monitoring for development of hypotension is advised during coadministration of these agents.

Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs.

Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

Volume of Distribution

In a pharmacolinetic study involving healthy volunteers receiving triamterene intravenously, the volumes of distribution of the central compartment of triamterene and its hydroxylated ester metabolite were 1.49 L/kg and 0.11 L/kg, respectively. Triamteren was found to cross the placental barrier and appear in the cord blood of animals.

Elimination Route

Triamteren is shown to be rapidly absorbed in the gastrointestinal tract Its onset of action achiveved within 2 to 4 hours after oral ingestion and its duration of action is 12-16 hours. It is reported that the diuretic effect of triamterene may not be observed for several days after administration. In a pharmacokinetic study, the oral bioavailability of triamterene was determined to be 52%. Following administration of a single oral dose to fasted healthy male volunteers, the mean AUC of triamterene was about 148.7 ng*hr/mL and the mean peak plasma concentrations (Cmax) were 46.4 ng/mL reached at 1.1 hour after administration. In a limited study, administration of triamterene in combination with hydrochlorothiazide resulted in an increased bioavailability of triamterene by about 67% and a delay of up to 2 hours in the absorption of the drug. It is advised that triamterene is administered after meals; in a limited study, combination use of triamterene and hydrochlorothiazide with the consumption of a high-fat meal resulted in an increase in the mean bioavailability and peak serum concentrations of triamterene and its active sulfate metabolite, as well as a delay of up to 2 hours in the absorption of the active constituents.

Half Life

The half-life of the drug in plasma ranges from 1.5 to 2 hours. In a pharmacokinetic study involving healthy volunteers, the terminal half-lives for triamterene and 4′-hydroxytriamterene sulfate were 255 ± 42 and 188 ± 70 minutes, respectively, after intravenous infusion of the parent drug.

Clearance

The total plasma clearance was 4.5 l/min and renal plasma clearance was 0.22 l/kg following intravenous administration of triamterene in healthy volunteers.

Elimination Route

Triamteren and its metabolites are excreted by the kidney by filtration and tubular secretion. Upon oral ingestion, somewhat less than 50% of the oral dose reaches the urine. About 20% of an oral dose appears unchanged in the urine, 70% as the sulphate ester of hydroxytriamterene and 10% as free hydroxytriamterene and triamterene glucuronide.

Innovators Monograph

You find simplified version here Triamteren

http://classyfire.wishartlab.com/tax_nodes/C0000000
http://classyfire.wishartlab.com/tax_nodes/C0000002
http://classyfire.wishartlab.com/tax_nodes/C0000109
http://classyfire.wishartlab.com/tax_nodes/C0000109
http://classyfire.wishartlab.com/tax_nodes/C0001262
http://classyfire.wishartlab.com/tax_nodes/C0001694
http://classyfire.wishartlab.com/tax_nodes/C0003886
http://classyfire.wishartlab.com/tax_nodes/C0002279
http://classyfire.wishartlab.com/tax_nodes/C0004144
http://classyfire.wishartlab.com/tax_nodes/C0004139
http://classyfire.wishartlab.com/tax_nodes/C0002450
http://classyfire.wishartlab.com/tax_nodes/C0004557
http://classyfire.wishartlab.com/tax_nodes/C0004150
http://www.hmdb.ca/metabolites/HMDB0001940
http://www.genome.jp/dbget-bin/www_bget?drug:D00386
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5546
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=46507623
https://www.chemspider.com/Chemical-Structure.5345.html
http://www.bindingdb.org/bind/chemsearch/marvin/MolStructure.jsp?monomerid=6644
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=10763
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=9671
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL585
https://zinc.docking.org/substances/ZINC000000120286
http://bidd.nus.edu.sg/group/cjttd/ZFTTDDRUG.asp?ID=DAP000575
http://www.pharmgkb.org/drug/PA451752
http://www.guidetopharmacology.org/GRAC/LigandDisplayForward?ligandId=4329
https://www.ebi.ac.uk/pdbe-srv/pdbechem/chemicalCompound/show/DX2
http://www.rxlist.com/cgi/generic/triamterine.htm
https://www.drugs.com/triamterene.html
https://en.wikipedia.org/wiki/Triamterene
*** Taking medicines without doctor's advice can cause long-term problems.
Share