Product Information
Registration Status: ActiveAPO-TRIAZIDE TABLET is approved to be sold in Singapore with effective from 1991-11-09. It is marketed by PHARMAFORTE SINGAPORE PTE LTD, with the registration number of SIN06552P.
This product contains Hydrochlorothiazide 25mg, and Triamterene 50mg in the form of TABLET. It is approved for ORAL use.
This product is manufactured by APOTEX INC in CANADA.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Description
A thiazide diuretic often considered the prototypical member of this class. It reduces the reabsorption of electrolytes from the renal tubules. This results in increased excretion of water and electrolytes, including sodium, potassium, chloride, and magnesium. It has been used in the treatment of several disorders including edema, hypertension, diabetes insipidus, and hypoparathyroidism. [PubChem]
Indication
For the treatment of high blood pressure and management of edema.
Mechanism of Action
Hydrochlorothiazide, a thiazide diuretic, inhibits water reabsorption in the nephron by inhibiting the sodium-chloride symporter (SLC12A3) in the distal convoluted tubule, which is responsible for 5% of total sodium reabsorption. Normally, the sodium-chloride symporter transports sodium and chloride from the lumen into the epithelial cell lining the distal convoluted tubule. The energy for this is provided by a sodium gradient established by sodium-potassium ATPases on the basolateral membrane. Once sodium has entered the cell, it is transported out into the basolateral interstitium via the sodium-potassium ATPase, causing an increase in the osmolarity of the interstitium, thereby establishing an osmotic gradient for water reabsorption. By blocking the sodium-chloride symporter, hydrochlorothiazide effectively reduces the osmotic gradient and water reabsorption throughout the nephron.
Pharmacokinetics
- Absorption
- 50-60%
- Distribution
- Metabolism
- Hydrochlorothiazide is not metabolized.
- Elimination
Toxicity
The most common signs and symptoms observed are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. If digitalis has also been administered, hypokalemia may accentuate cardiac arrhythmias. The oral LD50 of hydrochlorothiazide is greater than 10 g/kg in the mouse and rat.
Active Ingredient/Synonyms
HCTZ | Hydrochlorothiazide |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.
Description
A pteridine that is used as a mild diuretic. [PubChem]
Indication
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.
Mechanism of Action
Triamterene inhibits the epithelial sodium channels on principal cells in the late distal convoluted tubule and collecting tubule, which are responsible for 1-2% of total sodium reabsorption. As sodium reabsorption is inhibited, this increases the osmolarity in the nephron lumen and decreases the osmolarity of the interstitium. Since sodium concentration is the main driving force for water reabsorption, triamterene can achieve a modest amount of diuresis by decreasing the osmotic gradient necessary for water reabsorption from lumen to interstitium. Triamterene also has a potassium-sparing effect. Normally, the process of potassium excretion is driven by the electrochemical gradient produced by sodium reabsorption. As sodium is reabsorbed, it leaves a negative potential in the lumen, while producing a positive potential in the principal cell. This potential promotes potassium excretion through apical potassium channels. By inhibiting sodium reabsorption, triamterene also inhibits potassium excretion.
Pharmacokinetics
- Absorption
- Rapidly absorbed, with somewhat less than 50% of the oral dose reaching the urine.
- Distribution
- Metabolism
- Triamterene is primarily metabolized to the sulfate conjugate of hydroxytriamterene. Both the plasma and urine levels of this metabolite greatly exceed triamterene levels.
- Elimination
Clearance
* 4.5 l/min [total plasma clearance] * 0.22 l/kg [renal plasma clearance]
Toxicity
In the event of overdosage it can be theorized that electrolyte imbalance would be the major concern, with particular attention to possible hyperkalemia. Other symptoms that might be seen would be nausea and vomiting, other G.I. disturbances, and weakness. It is conceivable that some hypotension could occur. The oral LD50 in mice is 380 mg/kg.
Active Ingredient/Synonyms
6-phenylpteridine-2,4,7-triamine | Teridin | Triamteren | Triamtérène | Triamterene | Triamtereno | Triamterenum | Triamterene |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.