IP monotherapy as a strategy of simplification, after an induction period with standard triple therapy may be useful to minimize the risk of mitochondrial toxicity by NRTIs. Additionally, this strategy may be useful to improve treatment adherence, reduce costs and preserve future treatment options. In this sense, monotherapy with lopinavir / ritonavir (LPV / r) can be an effective option for the treatment of HIV-1 as a simplification strategy in routine clinical practice.3 OK04 study showed that in patients with sustained viral suppression simplified to monotherapy with LPV / r, rates of viral load <50 copies / mL were similar to that patients continuing on standard triple therapy.4, 5 However, the virological efficacy of this strategy in the CSF compartments has been questioned by some authors. Like most protease inhibitors, lopinavir has a poor penetration in CSF. Thus, despite the concentration of lopinavir in CSF usually exceed the inhibitory concentration (IC50) of wild strains of HIV, it is possible that some patients may present lopinavir concentrations insufficient to achieve sustained suppression of viral replication in that compartment. In this sense, according to results from a recent study, up to 10% of patients treated with lopinavir / ritonavir monotherapy may present detectable levels of viral load in CSF while maintaining a CV <50 copies / mL in plasma.9