Same patient, new stone composition: amprenavir urinary stone.

We report here the first case to add amprenavir to the growing list of antiretroviral drugs associated with urinary stones. The first reported case of a nelfinavir urinary stone was reported in 2002 in a 37-year-old HIV-infected woman. In September 2007, the same female patient was referred to our department with recent onset of right flank pain and recurrent urinary tract infections. Abdominal computed tomography revealed three obstructing stones in the distal right ureter, another stone in the right renal pelvis with hydronephrosis and a stone in the left kidney. After stone retrieval, analysis of the stone by liquid chromatography with mass spectrometry revealed a stone composition of 95% unmodified amprenavir and 5% ritonavir.