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abacavir (Ziagen)

Type of Drug: Nucleoside Reverse Transcriptase Inhibitor

Nucleoside reverse transcriptase inhibitors were the first type of drug available to treat HIV. They are also known as NRTIs, nucleoside analogues, or "nukes."

When the HIV virus enters a healthy cell, it attempts to make copies of itself. It does this by using an enzyme called reverse transcriptase. NRTIs block that enzyme, so HIV cannot make new copies of itself.

Approved adult dosing

one 300 mg tablet, two times a day

  • Morning

    Ziagen 300


  • Evening

    Ziagen 300


two 300 mg tablets, once a day

  • Once daily

    Ziagen 300Ziagen 300


Note: Generic formulations are available; these generic pills may have different shapes and colors than the one shown above.

Notes on taking this medication

  • No food restrictions, can take with or without food
  • Before taking Ziagen, you should be tested to see if you are at risk of an allergic reaction. The test is a blood test for a genetic marker called HLA B5701. If you are positive for HLA B5701, or have a history of allergy to abacavir (Ziagen) you cannot take it again.

Possible side effects

  • Mild nausea; vomiting; diarrhea; loss of appetite
  • Rash

Caution! Ziagen can cause a serious allergic reaction that includes at least 2 of the following: fever, malaise, severe nausea, diarrhea, abdominal pain, sore throat, cough, shortness of breath, and rash. Symptoms usually begin within 6 weeks of starting medication. Before taking Ziagen, you should be tested for HLA B5701.

If you think you are having an allergic reaction, call your doctor at once. If allergic, you will have to stop Ziagen and never take it again. Starting it again can cause serious illness or death. Make sure you tell your pharmacist if you are allergic to Ziagen.

See accompanying chart: Tips for Common Side Effects

My doctor's instructions

Scroll over drug name to see other names for the drug.