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
REFERENCES: 1. Daudon M, Jungers P. Drug-induced renal calculi: epidemiology, prevention
and management. Drugs. 2004;64:245-275. 2. Ettinger B, Oldroyd NO, Sorgel F. Triamterene nephrolithiasis. JAMA. 3. Matlaga BR, Shah OD, Assimos DG. Drug-induced urinary calculi. Rev Urol. 4. Sorgel F, Ettinger B, Benet LZ. The true composition of kidney stones passed
during triamtrene therapy. J Urol. 1985;134:871-873. 5. Carr MC, Prien EL Jr, Babayan RK. Triamterene nephrolithiasis: renewed
attention is warranted. J Urol. 1990;144:1339-1340. 6. 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. 1982;99:254-262. 658 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,
RELEASED WRITTEN EXAMINATION A periapical infection of a mandibular third molar One week after an amalgam restoration is placed in the mandibular first premolar, the patient returns complaining of a sharp pain of short duration when eating or drinking something cold. Teeth respond normally to electric pulp testing and heat and the radiographs are normal. The most likely diagnosis The mo
Triamterene Kidney Stones