[Dual therapy as an alternative treatment in HIV pretreated patients: experience in a tertiary hospital]. 
Dual therapy regimen might be an effective alternative to prevent the occurrence of side effects and comorbidities associated with prolonged treatment with antiretroviral (ARV) and a way of simplification of antiretroviral therapy (ART) to improve adherence in certain patients.  It also represents a potential treatment option for patients who have failed previous TAR.  The aim of the study is to describe the effectiveness, adherence and costs of dual therapy regimen used in pretreated HIV patients in tertiary hospital.  Thirty-eight patients were studied (eight were excluded).  Reasons for simplification to dual therapy were previous treatment toxicity (40%), simplification (36.67%) and virological rescue (20%).  The dual therapy regimens most used were: IP/r + INSTIs (26.67%), IP/r + NRTIs (23.33%), IP/r + NNR-TIs (23.33%), IP/r+ CCR5 (16.66%) e INSTIs + NNRTIs (10%).  ARV more used were darunavir/ritonavir (DRV/r) + raltegravir (23.33 %); DRV/r + lamivudine (20%) y DRV/r + etravirine (16.67 %).  Adherence was 86.79% before switching to dual therapy and 96.27% after switching.  The cost savings of switching to dual therapy of these patients was € 3,635.16.  Dual therapy with IP/r might be an effective alternative to selected treatment experienced patients compared with conventional therapy.