Dosing and uses of Dyrenium (triamterene)
Adult dosage forms and strengths
capsule
- 50mg
- 100mg
Edema
100-300 mg/day PO qDay or divided q12hr
Hypertension
100-300 mg/day PO qDay or divided q12hr
Renal Impairment
CrCl <10 mL: Do not use
Hepatic Impairment
Reduce dose in patients with cirrhosis
Other Information
Monitor serum potassium
See also combo with HCTZ
Pediatric dosage forms and strengths
capsule
- 50mg
- 100mg
Hypertension (Off-label)
Safety & efficacy not established
1-2 mg/kg/day PO divided q12hr
Maximum dose: 3-4 mg/kg/day PO divided q12hr up to 300 mg/day
Geriatric dosage forms and strengths
Consider lower initial doses
Edema
50-300 mg/day PO qDay or divided q12hr
Hypertension
50-300 mg/day PO qDay or divided q12hr
Dyrenium (triamterene) adverse (side) effects
1-10%
CHF
Edema
Hypotension
Dizziness
Fatigue
HA
Photosensitivity
Rash
Diarrhea
Nausea
Vomiting
Hyperuricemia
Nephrotoxicity
Frequency not defined
GI upset
Thrombocytopenia
Nephrolithiasis
Folic acid antagonism
Warnings
Contraindications
Hypersensitivity to triamterene
Anuria, severe liver disease, renal failure
Hyperkalemia
Concomitant use with K+-sparing diuretic, or K supplementation
Cautions
Acid-base imbalance, electrolyte abnormalities, hyperuricemia or gout, liver dz, renal impairment, renal stones
Breastfeeding
Interferes with fluorescent assay of quinidine
Not recommended for pregnancy-induced HTn
Use during pregnancy may increase risk of cardiovascular defects and oral cleft in child
Pregnancy and lactation
Pregnancy category: C
Lactation: Discontinue drug or nursing
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Dyrenium (triamterene)
Mechanism of action
Direct effect on renal distal tubule to inhibit Na+ reabsorption
Inhibits Na/K-ATPase, decreases Ca++ , Mg++ and hydrogen excretion
Pharmacokinetics
Half-Life: 1.5-2.5 hr
Duration: 7-9 hr
Onset: Initial effect: 2-4 hr; Max effect: diuresis: several days, HTN: 2-3 months
Peak Plasma Time: 1.5-3 hr
Bioavailability: 30-70%
Protein Bound: 55-67%
Metabolism: Liver
Metabolites: hydroxytriamterene sulfate (active)
Excretion: urine 21%
Dialyzable: Yes (hemodialysis)
