Abacavir (Ziagen, Epzicom and Trizivir)

Abacavir (Ziagen) is a FDA approved anti-HIV drug  in the  class of drugs  called nucleoside analogs  (NRTIs). Abacavir is used more frequently in  a combination two drug pill called Epzicom, or a three drug pill called Trizivir, although some people just take abacavir. Recent studies have shown that individuals with HLA B*5701 are those who are likely to develop an abacavir hypersensitivity reaction. Ask your doctor about getting  the test done before starting abacvir or Epzicom, a combination  of abacavir and lamivudine, to  prevent undue anxiety and worrying - as well as a hypersensitivity reaction. 

Taking the drug: 

The recommended dose of Ziagen  is one 300 mg pill  taken twice a day. Ziagen can be taken  with or without food.

For people that have already taken NRTI anti-HIV drugs, Ziagen may not always work so well due  to drug resistance. The changes in HIV that cause drug resistance are called mutations,  and different mutations cause resistance to different drugs. In clinical trials, if a person's HIV already had three  or more mutations that made it resistant  to other NRTI drugs, Ziagen did  not have anti-HIV effect. 

A set of rare but serious side effects of nucleoside analog anti-HIV drugs  is called lactic acidosis and severe hepatomegaly with steatosis (an enlarged fatty liver). Women, especially those  who are oveweight, are particularly at risk. This set of side effects is probably  the result  of mitochondrial toxicity.  Mitochondria  are cell's power organs that supply the energy  needed for normal cell growth. Anti-HIV nucleoside analogs impair the function of mitochondria. This can lead to increased acid levels  in the blood,  and an enlarged fatty liver. The symptoms are severe nausea, shortness  of breath  and vomiting that does  not get better.  If you are taking anti-HIV drugs and experience these symptoms, tell  your provider immediately.