Abacavir - Article abacavir sulfate; Ziagen
|Systematic (IUPAC) name|
|Bioavailability||Cmax=3.0 Â± 0.89 mcg/mL (dose of 300 mg bid, po)|
|Half life||1.54 Â± 0.63 hours|
|Excretion||Urine [1.2% abacavir, 30% 5'-carboxylic acid metabolite, 36% 5'-glucuronide metabolite, 15% unidentified minor metabolites]. Fecal [16%]|
|Pregnancy cat.|| |
|Legal status|| |
|Routes||Oral (solution or tablets)|
Abacavir (ABC) is the most powerful nucleoside analog reverse transcriptase inhibitor (NARTI) used to treat HIV and AIDS. It is available under the trade name Ziagenâ„¢ (GlaxoSmithKline} and the combination drugs Trizivirâ„¢(abacavir, zidovodine and lamivudine) and KivexaÂ®/Epzicomâ„¢(abacavir and lamivudine) . It has been well tolerated; its main side effect being hypersensitivity reactions, which can be dangerous or even (in some rare cases) fatal. Fortunately, genetic testing can indicate beforehand whether an individual will be hypersensitive; over 90% of patients can safely take abacavir.
Abacavir was approved by the Food and Drug Administration (FDA) on December 18, 1998 and is thus the fifteenth approved antiretroviral drug in the United States. Its patent will expire in the United States on 2009-12-26.
Mechanism of Action
ABC is an analog of guanosine. It is capable of crossing the blood-brain barrier.
Abacavir is given orally and has a high bio-availability (83%). It is metabolised primarily through alcohol dehydrogenase or gluconyl transferase.
Fatal hypersensitivity reactions have been associated with therapy with abacavir. Symptoms of hypersensitivity include fever, skin rash, fatigue, gastrointestinal symptoms such as nausea, vomiting, diarrhea or abdominal pain and respiratory symptoms such as pharyngitis, dyspnea, or cough.
Abacavir should always be used in combination with other antiretroviral agents. Abacavir should not be added as a single agent when antiretroviral regimens are changed due to loss of virologic response.