Switching From Tenofovir Disoproxil Fumarate to Abacavir or Tenofovir Alafenamide

Tenofovir disoproxil fumarate (TDF) is one of the most frequently used drugs to treat HIV. Long term use of TDF can induce renal toxicity. Tenofovir alafenamide (TAF) is a new pro-drug of Tenofovir which has not been associated with renal toxicity and may therefore be a good substitute for TDF in patients with TDF induced renal toxicity. Abacavir (ABC) is another drug that can be used for the treatment of HIV and is not associated with renal toxicity. In this study the investigators will compare the effect on renal function of a switch from TDF to TAF with a switch from TDF to ABC in patients with TDF induced renal insufficiency.