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 .
