Thrombotic microangiopathy and acute kidney injury associated with intravenous abuse of an oral extended-release formulation of oxymorphone hydrochloride: kidney biopsy findings and report of 3 cases.

There have been recent reports and warnings of a thrombotic thrombocytopenic purpura-like illness associated with intravenous abuse of a prescription narcotic intended for oral use. Oral extended-release oxymorphone hydrochloride (Opana ER) is an opioid agonist that has undergone a tamper-resistant reformulation. However, instances of melting and dissolving tablets with subsequent injection continue to occur. We report 3 cases of hemolytic anemia and acute kidney injury associated with intravenous abuse of this reformulated drug. All 3 patients underwent native kidney biopsy that showed thrombotic microangiopathy characterized by severe arterial and arteriolar mucoid intimal edema with resultant glomerular and tubular ischemia. All 3 patients required hemodialysis and 2 also underwent therapeutic plasma exchange. Early follow-up suggests that kidney outcome is poor, with only partial recovery of function despite aggressive treatment. The specific component or components of this reformulated drug associated with endothelial injury is unknown. Most importantly, a high degree of clinical suspicion is needed when treating patients with a thrombotic thrombocytopenic purpura-like illness of unknown cause.