Background and aim: Antiretroviral drugs can cause drug interactions.
Material and methods: Three clinical cases are described regarding HIV-infected patients in which a clinically relevant adverse effect occurred due to a pharmacokinetic interaction.
Results: Case 1: A 43-year old woman being treated with tenofovir DF, emtricitabine and lopinavir/ritonavir who presents ischemia in both upper extremities following an ergotamine syndrome. Case 2: A 54-year old man being treated with zidovudine, lamivudine and lopinavir/ritonavir who presents Cushing syndrome following to use of inhaled fluticasone. Case 3: A 45-year old man being treated with tenofovir DF, emtricitabine and atazanavir/ritonavir who presents a virological failure as consequence of concomitant use of omeprazole.
Conclusions: Potential drug interactions must be considered when other concomitant drugs are used with antiretroviral therapy especially when one of these is a P 450 cytochrome enzymatic inductor or inhibitor.