Article: Abacavir

Abacavir
Systematic (IUPAC) name
[(1R)-4-[2-amino- 6-(cyclopropylamino)purin- 9-yl]-1-cyclopent- 2-enyl]methanol
Identifiers
CAS number	?
ATC code	J05AF06
PubChem	441300
DrugBank	?
Chemical data
Formula	C14H18N6O
Mol. weight	286.333
Pharmacokinetic data
Bioavailability	Cmax=3.0 ± 0.89 mcg/mL (dose of 300 mg bid, po)
Metabolism	Liver
Half life	1.54 ± 0.63 hours
Excretion	Urine [1.2% abacavir, 30% 5'-carboxylic acid metabolite, 36% 5'-glucuronide metabolite, 15% unidentified minor metabolites]. Fecal [16%]
Therapeutic considerations
Pregnancy cat.	C (USA)  ? (Aus
Legal status	POM
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 Ziagen™ (GlaxoSmithKline} and the combination drugs Trizivir™(abacavir, zidovodine and lamivudine) and Kivexa®/Epzicom™(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.

Two (2) Abacavir 300mg tablets

Viral strains that are resistant to zidovudine (AZT) or lamivudine (3TC) are generally sensitive to abacavir, whereas strains that are resistant to AZT and 3TC are not as sensitive to abacavir.

History

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.

Indication

Abacavir tablets and oral solution, in combination with other antiretroviral agents, are indicated for the treatment of HIV-1 infection.

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.

Adverse Reactions

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.