PI Perspective #26

December 1998     View PDF     En español

Abacavir Update

As we go to press, the Antiviral Drugs Advisory Committee to the Food and Drug Administration (FDA) recommended that abacavir (Ziagen) be approved to treat HIV disease for adults and children. Abacavir is expected to be available in pharmacies before the end of the year. Abacavir will be the sixth nucleoside analogue drug to be approved by the FDA, the others being AZT (zidovudine, Retrovir), ddI (didanosine, Videx), ddC (zalcitabine, Hivid), d4T (stavudine, Zerit) and 3TC (lamivudine, Epivir).

Studies suggest that abacavir has the most potent anti-HIV activity of all the drugs in its class, when used by people who have not previously been on any anti-HIV therapies. However, for people who have developed resistance to multiple previous therapies, the potency of abacavir tends to drop substantially.

The recommended dose of abacavir is 300mg (a single pill) twice a day for a total daily dose of 600mg. When it is used in combination with AZT and 3TC (Combivir), the total regimen requires only two pills twice a day (four pills total, per day).

The simplicity of the regimen is expected to be one of its most attractive features. The recommended dose for children is 8.0mg/kg taken twice a day. Abacavir can be taken without regards to food.

The most common side effects reported in the clinical studies are nausea, fatigue, headaches and diarrhea. A more serious side effect which affects about 3% of people taking abacavir is a hypersensitivity reaction to the drug. This reaction is usually systemic (throughout the body) and includes fevers, malaise, nausea, vomiting and sometimes rash. This reaction appears relatively soon after starting abacavir (about two weeks) and resolves one or two days after stopping the drug. It is important not to try and take abacavir again (re-challenge) if there was hypersensitivity to the drug as the subsequent reaction is potentially fatal.