GENERIC NAME: abacavir

BRAND NAME: Ziagen

DRUG CLASS AND MECHANISM: Abacavir is an oral medication that is used for the treatment of infections with the human immunodeficiency virus (HIV). It is in a class of drugs called reverse transcriptase inhibitors which also includes zalcitabine (Hivid), zidovudine (Retrovir), didanosine (Videx), lamivudine (Epivir) and stavudine (Zerit). During infection with HIV, the HIV virus multiplies within the body's cells. The newly-formed viruses then are released from the cells and spread throughout the body where they infect other cells. In this manner, the infection continually spreads to new, uninfected cells that the body is continually producing, and HIV infection is perpetuated. When producing new viruses, the HIV virus must manufacture new DNA for each virus. Reverse transcriptase is the enzyme that the virus uses to form this new DNA. Specifically, abacavir is converted within the body to its active form (carbovir triphosphate). This active form is similar to a compound (deoxyguanosine triphosphate), a chemical that is required by the HIV virus to make new DNA. The reverse transcriptase uses carbovir triphosphate instead of deoxyguanosine triphosphate for making DNA, and it is the carbovir triphosphate that interferes with the reverse transcriptase. Abacavir does not kill existing HIV virus and it is not a cure for HIV. The FDA approved abacavir in December, 1998.

GENERIC AVAILABLE: No

PRESCRIPTION: Yes

PREPARATIONS: Tablets: 300 mg; oral solution 20 mg/ml

STORAGE: Store capsules and solution at room temperature, 15-30°C (59-86°F). The oral solution may be refrigerated but should not be frozen.

PRESCRIBED FOR: Abacavir is used in combination with other anti-HIV drugs for the treatment of HIV infection.

DOSING: The recommended dose for adults is 300 mg twice daily or 600 mg once daily. Children (3 months and older) should receive 8 mg/kg twice daily, and the maximum recommended dose is 300 mg twice daily.

Abacavir may be administered with or without food since food does not affect its absorption.

DRUG INTERACTIONS: Alcohol competes with abacavir for elimination from the body. Therefore, alcohol consumption may increase the concentration of abacavir in the body and this could lead to increased frequency or severity of side effects from abacavir. Abacavir does not affect the elimination of alcohol.

PREGNANCY: Use of abacavir during pregnancy has not been adequately evaluated.

NURSING MOTHERS: It is not known whether abacavir is excreted in breast milk. HIV infected mothers should not breast feed because of the potential risk of transmitting HIV to an infant that is not infected.

SIDE EFFECTS: The most common side effects are nausea, vomiting, diarrhea, loss of appetite and difficulty sleeping. The most serious side effects are severe allergic reactions, pancreatitis, liver failure and metabolic disturbance (lactic acidosis). Symptoms of an allergic reaction include skin rash, fever, weakness, swelling and difficulty breathing.

Reference: FDA Prescribing Information