Justice AC, Zingmond DS, Gordon KS, Fultz SL, Goulet JL, King JT, Bravata DM, Valdez H, Kraft M, Mattocks KM. Drug toxicity, HIV progression, or comorbidity of aging: does tipranavir use increase the risk of intracranial hemorrhage? Clin Infect Dis. 2008 Nov 01; 47(9):1226-30.