Triamterene
CLINICAL USE
Diuretic (potassium-sparing)
DOSE IN NORMAL RENAL FUNCTION
150–250 mg daily in divided doses; reduce to alternate days after 1 week
PHARMACOKINETICS
Molecular weight : 253 %Protein binding : 60 %Excreted unchanged in urine : 5–10 Volume of distribution (L/kg) : 2.2–3.7 half-life – normal/ESRD (hrs) : 2/10 DOSE IN RENAL IMPAIRMENT
GFR (mL/MIN)
20 to 50 : Dose as in normal renal function 10 to 20 : Avoid. See ‘Other Information’ <10 : Avoid. See ‘Other Information’ DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES
CAPD : Unknown dialysability. Avoid HD : Unknown dialysability. Avoid HDF/high flux : Unknown dialysability. Avoid CAV/VVHD : Unknown dialysability. Avoid IMPORTANT DRUG INTERACTIONS
Potentially hazardous interactions with other drugs ACE inhibitors and angiotensin-II antagonists: enhanced hypotensive effect (risk of severe hyperkalaemia) Analgesics: increased risk of nephrotoxicity with NSAIDs; increased risk of hyperkalaemia, especially with indometacin; antagonism of hypotensive effect Antibacterials: avoid concomitant use with lymecycline Antidepressants: enhanced hypotensive effect with MAOIs; increased risk of postural hypotension with tricyclics Antipsychotics: enhanced hypotensive effect with phenothiazines Antihypertensives: enhanced hypotensive effect; increased risk of first dose hypotensive effect of post-synaptic alpha- blockers, e.g. prazosin Ciclosporin: increased risk of hyperkalaemia Lithium: reduced excretion of lithium (risk of lithium toxicity) Potassium salts: increased risk of hyperkalaemia Tacrolimus: increased risk of hyperkalaemia ADMINISTRATION
Reconstition
– Route
Oral Rate of Administration
– Comments
– OTHER INFORMATION
Hyperkalaemia is common when GFR<30 mL/min. May cause acute renal failure Potassium-sparing diuretics are weak diuretics and are ineffective in moderate to severe renal failure .
See how to identify renal failure stages according to GFR calculation
See how to diagnose irreversible renal disease
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