What is Abacavir Sulfate?
Abacavir is a Nucleoside Reverse Transcriptase Inhibitor (NRTI) drug used in combination with other antiretroviral drugs for the treatment of HIV. Abacavir works as a nucleoside substrate and acts as a chain terminator, so it is able to disrupt viral replication.
Dosing & Administration
Abacavir is indicated for the treatment of an HIV infection in adults and children three months old and up that weigh at least 14 Kg; it works as part of a combination drug regimen. It is also used off-label as part of a drug regimen for occupational HIV post-exposure prophylaxis. The oral tablets may be crushed, and it is available in an oral solution. The drug may be taken without regard to meals. Additional dosage and administration instructions are detailed in the product’s package insert.
Abacavir requires a dosage reduction and close monitoring in patients with mild liver dysfunction. No dosage adjustments are required in patients with renal impairment, but this HIV/AIDS medication should not be used in end-stage renal disease. More specific information about dosage reduction is given in the package insert.
Abacavir is contraindicated in patients with a hypersensitivity to the drug or any of its other components.
Abacavir Side Effects
It may cause severe hypersensitivity reactions. The package insert contains a complete list of potential adverse effects.
Abacavir may cause serious and potentially even fatal hypersensitivity reactions, including anaphylaxis. Patients should be tested for HLA-B*5701 prior to initiating treatment with this drug, but hypersensitivity to abacavir may occur in patients who are not positive for HLA-B*5701.
The drug may increase the risk for a myocardial infarction, so it may not be appropriate for patients with any underlying cardiac risk.
It may cause lactic acidosis or hepatotoxicity, including fatal cases, and should be used with caution or not at all in patients with liver impairment or risk factors for liver disease. Patients should be screened and monitored as described in the product’s package insert.
All HIV-positive patients should be screened for a comorbid Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infection. Co-infected patients should be started on an antiretroviral regimen targeting co-infected viruses, regardless of CD4 counts or viral loads. Current HIV treatment guidelines outline drug regimens and prescribing considerations.
Abacavir is associated with a large number of drug-drug interactions. A complete list of these interactions is provided in the package insert.
Pregnancy & Lactation
Highly-active retroviral combination treatment should be used in all pregnant women, regardless of viral load and CD4 count. Data from the Antiretroviral Pregnancy Registry do not show that abacavir causes major birth defects above the baseline. However, there are theoretical risks to the fetus and neonate, and pregnant women may be at increased risk of lactic acidosis and liver toxicity. Current guidelines should be consulted when treating women in pregnancy.
Abacavir is excreted in breast milk. The CDC recommends that all HIV-positive women, treated or untreated, avoid breastfeeding to prevent the vertical transmission of the virus.
There is no known antidote for an overdose of abacavir, so standard supportive treatment should be used. It is unknown if this medication can be hemodialyzed.
Alternative Brand Names
Abacavir is also available under the brand name Ziagen.