| Item |
Information |
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Drug Groups
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approved |
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Description
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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. |
| Pharmacology |
Triamterene, a relatively weak, potassium-sparing diuretic and antihypertensive, is used in the management of hypokalemia. Triamterene is similar in action to amiloride but, unlike amiloride, increases the urinary excretion of magnesium. |
| 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. |
| Affected Organisms |
| • |
Humans and other mammals |
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| Biotransformation |
Triamterene is primarily metabolized to the sulfate conjugate of hydroxytriamterene. Both the plasma and urine levels of this metabolite greatly exceed triamterene levels. |
| Absorption |
Rapidly absorbed, with somewhat less than 50% of the oral dose reaching the urine. |
| Half Life |
255 minutes (188 minutes for OH-TA-ester metabolite) after IV administration. |
| Protein Binding |
55-67% (93% for the OH-TA-ester metabolite) |
| Clearance |
* 4.5 l/min [total plasma clearance]
* 0.22 l/kg [renal plasma clearance] |
| References |
| • |
WellSpring Pharmaceutical Corporation. Dyrenium (triamterene) capsules prescribing information. Neptune, NJ; 2001 June. |
| • |
Gilfrich HJ, Kremer G, Mohrke W, Mutschler E, Volger KD: Pharmacokinetics of triamterene after i.v. administration to man: determination of bioavailability. Eur J Clin Pharmacol. 1983;25(2):237-41.
[Pubmed]
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