Ditide

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

Benzthiazide is used to treat hypertension and edema. Like other thiazides, benzthiazide promotes water loss from the body (diuretics). They inhibit Na+/Cl- reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of potassium and an increase in serum uric acid. Thiazides are often used to treat hypertension, but their hypotensive effects are not necessarily due to their diuretic activity. Thiazides have been shown to prevent hypertension-related morbidity and mortality although the mechanism is not fully understood. Thiazides cause vasodilation by activating calcium-activated potassium channels (large conductance) in vascular smooth muscles and inhibiting various carbonic anhydrases in vascular tissue.

Triamterene (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. Triamterene is a weak antagonist of folic acid, and a photosensitizing drug.

Triamterene 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.

Triamterene, 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. Triamterene 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 Ditide
Generic Benzthiazide + Triamterene
Weight 50mg
Type Tablet
Therapeutic Class
Manufacturer Glaxosmithkline
Available Country India
Last Updated: September 19, 2023 at 7:00 am
Ditide
Ditide

Uses

For the treatment of high blood pressure and management of edema.

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

Triamterene 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.

Triamterene 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. Triamterene allows the maintenance of potassium balance when given in combination with loop diuretics and thiazides.

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

How Ditide works

As a diuretic, benzthiazide inhibits active chloride reabsorption at the early distal tubule via the Na-Cl cotransporter, resulting in an increase in the excretion of sodium, chloride, and water. Thiazides like benzthiazide also inhibit sodium ion transport across the renal tubular epithelium through binding to the thiazide sensitive sodium-chloride transporter. This results in an increase in potassium excretion via the sodium-potassium exchange mechanism. The antihypertensive mechanism of benzthiazide is less well understood although it may be mediated through its action on carbonic anhydrases in the smooth muscle or through its action on the large-conductance calcium-activated potassium (KCa) channel, also found in the smooth muscle.

Triamterene 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. Triamterene 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. Triamterene 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. Triamterene is similar in action to amiloride but, unlike amiloride, increases the urinary excretion of magnesium.

Toxicity

Symptoms of overdose include nausea, vomiting, fatigue, urinary problems and drowsiness.

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.

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. Triamterene was found to cross the placental barrier and appear in the cord blood of animals.

Elimination Route

Absorbed in the digestive tract.

Triamterene 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

Triamterene 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.

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