Key takeaways
Abacavir (brand name Ziagen) and didanosine (brand name Videx) are both antiretroviral (ARV) medications used to treat HIV. They should each be used with other HIV medications for the treatment of HIV. They belong to the same drug class called nucleoside reverse transcriptase inhibitors (NRTIs), which help prevent the HIV virus from making copies of itself. However, there are several differences between the two. Abacavir is still available and can be taken as a tablet or oral solution, while didanosine has been discontinued in the U.S. due to serious side effects and limited use. Abacavir requires a genetic test before starting because it can cause a severe allergic reaction, whereas didanosine was known for causing other serious side effects, which contributed to its discontinuation. Abacavir is available as a generic, but didanosine is not available in any form. Abacavir can be used in children as young as 3 months old, while didanosine had more restrictions. Additionally, abacavir has fewer drug interactions compared to didanosine, which could not be taken with certain other HIV medications.
