**10.1. Tenofovir Disoproxil Fumarate (TDF)/Emtricitabine (FTC)**

The combination TDF/FTC (Truvada®, TVD), both NRTIs, widely used as part of first-line regimens for the treatment of HIV-1 infection, was approved in July 2012 by the FDA for PrEP in combination with safer sex practices to reduce the risk of sexually acquired HIV-1 in highrisk adults [181]. Currently, prescribing daily oral PrEP with TDF 300mg/FTC 200 is recom‐ mended as one prevention option for MSM, heterosexual patners, and IDU at substantial risk of HIV acquisition [181-183]. TDF/FTC has had few serious side effects, which facilitates adherence to its use, however, it can't be administered to subjects with renal failure and


**Table 5.** Clinical trials with TDF/FTC (Truvada®) for pre-exposure prophylaxis (PrEP)(GRADE Criteria). Note: Grade quality rating: high=further research is very unlikely to change our confidence in the estimate of effect; moderate=further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate;low= further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate; very low=any estimate of effect is very uncertain. \*All trials in this table were randomized, double-blind, prospective clinical trials.

Fanconi syndrome [177-179, 184]. Additionally, its use in PrEP is well tolerated, and the occurrence of headache, nausea, vomiting, abdominal pain, and weight loss may occur infrequently [177-179]. Nausea and vomiting affects about one in six patients at the beginning of the treatment, but these effects often reduce in the first month [177]. Although the use of TDF/FTC may be in a single daily dose, it is important to assess the risk of developing drug resistance. Thus, it is necessary for all patients to be seronegative for HIV-1 before beginning treatment, to perform laboratory tests every two or three months, in order to confirm their seronegative status for HIV-1 [185]. In individuals with signs and/or symptoms of acute HIV-1 infection, or who reported ppotential HIV-1 exposure in the previous month, HIV-1 infection should be excluded by repeated tests before starting PrEP [177, 179, 185]. Further, the starting of PrEP with TDF/FTC requires that individuals carry out medical examinations and screening for diagnosing possible STI in six-month intervals [185-190]. The main clinical studies of TDF/ FTC and TDF monotherapy, which allowed the approval of this therapy as choice for PrEP, are shown in Table 5.
