Triamterene Kidney Stones
FaDI I. Jabr, mD
A64-year-old woman with a history of recur-
rent kidney stones presented with severe
left flank pain radiating to the left lower
quadrant of 4 days’ duration. She brought
that she had passed in urine. Her medications included
hydrochlorothiazide, 25 mg/triamterene, 37.5 mg.
An abdominal radiograph (A
) and a CT scan of the
kidneys, ureters, and bladder (B
) showed bilateral renal
calcifications. On the right, the largest was 3 mm, and
on the left, multiple punctate calcifications were evident.
Urinalysis was positive for trace blood and trace leuko-
cytes. The analysis of the stone revealed triamterene
composition. The patient underwent successful place-
ment of ureteral stents to help passage of the stones fol-
nucleus of the stone or was deposited with calcium
In the 1970s, triamterene was the major cause of
oxalate or uric acid; this finding suggests that in the
drug-induced renal calculi.1 In a 1980 study, the estimat-
majority of cases, triamterene lithiasis develops in per-
ed annual incidence of triamterene lithiasis was 1 per
sons who have had renal stones.2 It becomes incorpo-
1500 users of triamterene/hydrochlorothiazide.2 Triam-
rated into existing stone nidi by binding to the protein
terene was found in 0.4% (181 of 50,000) of renal calculi
submitted for analysis.2 This percentage has probably
Treatment consists of discontinuation of the medi-
changed in recent years because indinavir and sulfadia-
cation and lithotripsy, because the calculi cannot be
zine are now the most common causes of drug-contain-
dissolved by pH manipulation.3 On plain radiographs,
ing renal stones.1,3 Triamterene is still responsible, how- triamterene stones are—as in this case—faintly radio-
ever, for many drug-induced calculi.
paque and are less dense than calcium oxalate stones.
Both unchanged triamterene and its metabolites,
They are more detectable on a CT scan of the kidneys,
hydroxytriamterene and sulfate ester of hydroxytriam-
terene, are present in triamterene stones.4 Up to one
This case illustrates the need to be cautious in the
third of triameterene stones consist entirely of triam-
use of triamterene, particularly in patients who are pre-
terene.2,5 In the remainder, triameterene formed the
disposed to nephrolithiasis or who have a prior history
of kidney stones, to avoid the formation of new calculi.
This caution applies even when triamterene is used in
Daudon M, Jungers P. Drug-induced renal calculi: epidemiology, prevention
and management. Drugs.
Ettinger B, Oldroyd NO, Sorgel F. Triamterene nephrolithiasis. JAMA.
Matlaga BR, Shah OD, Assimos DG. Drug-induced urinary calculi. Rev Urol.
Sorgel F, Ettinger B, Benet LZ. The true composition of kidney stones passed
during triamtrene therapy. J Urol.
Carr MC, Prien EL Jr, Babayan RK. Triamterene nephrolithiasis: renewed
attention is warranted. J Urol.
Werness PG, Bergert JH, Smith LH. Triamterene urolithiaisis: solubility, pH,
effect on crystal formation, and matrix binding of triamterene and its metabolites.
J Lab Clin Med.
Consultant september 2011
Interview with Marjorie Herdes and William Stockton: Practitioners of the Year. By Christine Herdes MARK YOUR CALENDARS Upcoming MNODN Monthly Meetings March 4th 3:30 – 5:30 pm, Finding Your Compass: Aligning Organizational Culture with Development Network recognizes an individual who has made significant It’s my understanding that the award was April 1st 3:30 – 5:30 pm,
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