Abacavir
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];
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Black Box Warning
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WARNING: RISK OF HYPERSENSITIVITY REACTIONS, LACTIC ACIDOSIS, AND SEVERE HEPATOMEGALY
See full prescribing information for complete Boxed Warning.
* Hypersensitivity Reactions: Serious and sometimes fatal hypersensitivity reactions have been associated with ZIAGEN® (abacavir sulfate).
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Overview
Abacavir is a Adrenergic receptor agonist that is FDA approved for the {{{indicationType}}} of a list of indications, separated by commas.. There is a Black Box Warning for this drug as shown here. Common adverse reactions include a list of adverse reactions, separated by commas..
Adult Indications and Dosage
FDA-Labeled Indications and Dosage (Adult)
Condition 1
- Dosing Information
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Condition 2
- Dosing Information
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Off-Label Use and Dosage (Adult)
Guideline-Supported Use
Condition 1
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
- Dosing Information/Recommendation
- (Dosage)
Condition 2
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
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Non–Guideline-Supported Use
Condition 1
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Condition 2
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Condition 3
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Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
Condition 1
- Dosing Information
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Condition 2
- Dosing Information
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Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
Condition 1
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
- Dosing Information/Recommendation
- (Dosage)
Condition 2
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
- Dosing Information/Recommendation
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Non–Guideline-Supported Use
Condition 1
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Condition 2
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Condition 3
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Contraindications
ZIAGEN is contraindicated in patients with:
- Previously demonstrated hypersensitivity to abacavir or any other component of the products.
- NEVER restart ZIAGEN or any other abacavir-containing product following a hypersensitivity reaction to abacavir, regardless of HLA-B*5701 status.
- Moderate or severe hepatic impairment [see Dosage and Administration].[1]
Warnings
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WARNING: RISK OF HYPERSENSITIVITY REACTIONS, LACTIC ACIDOSIS, AND SEVERE HEPATOMEGALY
See full prescribing information for complete Boxed Warning.
* Hypersensitivity Reactions: Serious and sometimes fatal hypersensitivity reactions have been associated with ZIAGEN® (abacavir sulfate).
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Conidition 1
(Description)
Adverse Reactions
Clinical Trials Experience
Central Nervous System
- (list/description of adverse reactions)
Cardiovascular
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Respiratory
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Gastrointestinal
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Hypersensitive Reactions
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Miscellaneous
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Condition 2
Central Nervous System
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Cardiovascular
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Respiratory
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Gastrointestinal
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Hypersensitive Reactions
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Miscellaneous
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Postmarketing Experience
(Description)
Drug Interactions
In human liver microsomes, abacavir did not inhibit cytochrome P450 isoforms (2C9, 2D6, 3A4). Based on these data, it is unlikely that clinically significant drug interactions will occur between abacavir and drugs metabolized through these pathways.
Lamivudine and/or Zidovudine
Due to the common metabolic pathways of abacavir and zidovudine via glucuronyl transferase, 15 HIV-1-infected subjects were enrolled in a crossover trial evaluating single doses of abacavir (600 mg), lamivudine (150 mg), and zidovudine (300 mg) alone or in combination. Analysis showed no clinically relevant changes in the pharmacokinetics of abacavir with the addition of lamivudine or zidovudine or the combination of lamivudine and zidovudine. Lamivudine exposure (AUC decreased 15%) and zidovudine exposure (AUC increased 10%) did not show clinically relevant changes with concurrent abacavir.
Ethanol
Due to the common metabolic pathways of abacavir and ethanol via alcohol dehydrogenase, the pharmacokinetic interaction between abacavir and ethanol was studied in 24 HIV-1-infected male subjects. Each subject received the following treatments on separate occasions: a single 600-mg dose of abacavir, 0.7 g/kg ethanol (equivalent to 5 alcoholic drinks), and abacavir 600 mg plus 0.7 g/kg ethanol. Coadministration of ethanol and abacavir resulted in a 41% increase in abacavir AUC∞ and a 26% increase in abacavir t1/2. In males, abacavir had no effect on the pharmacokinetic properties of ethanol, so no clinically significant interaction is expected in men. This interaction has not been studied in females.
Methadone
In a trial of 11 HIV-1-infected subjects receiving methadone-maintenance therapy (40 mg and 90 mg daily), with 600 mg of ZIAGEN twice daily (twice the currently recommended dose), oral methadone clearance increased 22% (90% CI: 6% to 42%). This alteration will not result in a methadone dose modification in the majority of patients; however, an increased methadone dose may be required in a small number of patients. The addition of methadone had no clinically significant effect on the pharmacokinetic properties of abacavir.
Use in Specific Populations
Pregnancy
Pregnancy Category (FDA):
(Description)
Pregnancy Category (AUS):
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Labor and Delivery
(Description)
Nursing Mothers
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Pediatric Use
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Geriatic Use
(Description)
Gender
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Race
(Description)
Renal Impairment
(Description)
Hepatic Impairment
(Description)
Females of Reproductive Potential and Males
(Description)
Immunocompromised Patients
(Description)
Others
(Description)
Administration and Monitoring
Administration
(Oral/Intravenous/etc)
Monitoring
Condition 1
(Description regarding monitoring, from Warnings section)
Condition 2
(Description regarding monitoring, from Warnings section)
Condition 3
(Description regarding monitoring, from Warnings section)
IV Compatibility
Solution
Compatible
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Not Tested
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Variable
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Incompatible
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Y-Site
Compatible
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Not Tested
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Variable
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Incompatible
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Admixture
Compatible
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Not Tested
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Variable
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Incompatible
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Syringe
Compatible
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Not Tested
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Variable
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Incompatible
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TPN/TNA
Compatible
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Not Tested
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Variable
- Solution 1
- Solution 2
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Incompatible
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Overdosage
Acute Overdose
Signs and Symptoms
(Description)
Management
(Description)
Chronic Overdose
Signs and Symptoms
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Management
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Pharmacology
Abacavir
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Mechanism of Action
Abacavir is an antiviral agent
Structure
(Description with picture)
Pharmacodynamics
(Description)
Pharmacokinetics
Pharmacokinetics in Adults
The pharmacokinetic properties of abacavir have been studied in asymptomatic, HIV-1-infected adult subjects after administration of a single intravenous (IV) dose of 150 mg and after single and multiple oral doses. The pharmacokinetic properties of abacavir were independent of dose over the range of 300 to 1,200 mg/day.
Absorption and Bioavailability
Abacavir was rapidly and extensively absorbed after oral administration. The geometric mean absolute bioavailability of the tablet was 83%. After oral administration of 300 mg twice daily in 20 subjects, the steady-state peak serum abacavir concentration (Cmax) was 3.0 ± 0.89 mcg/mL (mean ± SD) and AUC(0-12 hr) was 6.02 ± 1.73 mcg•hr/mL. After oral administration of a single dose of 600 mg of abacavir in 20 subjects, Cmax was 4.26 ± 1.19 mcg/mL (mean ± SD) and AUC∞ was 11.95 ± 2.51 mcg•hr/mL.
Distribution
The apparent volume of distribution after IV administration of abacavir was 0.86 ± 0.15 L/kg, suggesting that abacavir distributes into extravascular space. In 3 subjects, the CSF AUC(0-6 hr) to plasma abacavir AUC(0-6 hr) ratio ranged from 27% to 33%. Binding of abacavir to human plasma proteins is approximately 50%. Binding of abacavir to plasma proteins was independent of concentration. Total blood and plasma drug-related radioactivity concentrations are identical, demonstrating that abacavir readily distributes into erythrocytes.
Metabolism
In humans, abacavir is not significantly metabolized by cytochrome P450 enzymes. The primary routes of elimination of abacavir are metabolism by alcohol dehydrogenase (to form the 5′-carboxylic acid) and glucuronyl transferase (to form the 5′-glucuronide). The metabolites do not have antiviral activity. In vitro experiments reveal that abacavir does not inhibit human CYP3A4, CYP2D6, or CYP2C9 activity at clinically relevant concentrations.
Elimination
Elimination of abacavir was quantified in a mass balance trial following administration of a 600-mg dose of 14C-abacavir: 99% of the radioactivity was recovered, 1.2% was excreted in the urine as abacavir, 30% as the 5′-carboxylic acid metabolite, 36% as the 5′-glucuronide metabolite, and 15% as unidentified minor metabolites in the urine. Fecal elimination accounted for 16% of the dose. In single-dose trials, the observed elimination half-life (t1/2) was 1.54 ± 0.63 hours. After intravenous administration, total clearance was 0.80 ± 0.24 L/hr/kg (mean ± SD). Effects of Food on Oral Absorption: Bioavailability of abacavir tablets was assessed in the fasting and fed states. There was no significant difference in systemic exposure (AUC∞) in the fed and fasting states; therefore, ZIAGEN Tablets may be administered with or without food. Systemic exposure to abacavir was comparable after administration of ZIAGEN Oral Solution and ZIAGEN Tablets. Therefore, these products may be used interchangeably.
Special Populations
Renal Impairment: The pharmacokinetic properties of ZIAGEN have not been determined in patients with impaired renal function. Renal excretion of unchanged abacavir is a minor route of elimination in humans.
Hepatic Impairment
The pharmacokinetics of abacavir have been studied in subjects with mild hepatic impairment (Child-Pugh score 5 to 6). Results showed that there was a mean increase of 89% in the abacavir AUC and an increase of 58% in the half-life of abacavir after a single dose of 600 mg of abacavir. The AUCs of the metabolites were not modified by mild liver disease; however, the rates of formation and elimination of the metabolites were decreased. A dose of 200 mg (provided by 10 mL of ZIAGEN Oral Solution) administered twice daily is recommended for patients with mild liver disease. The safety, efficacy, and pharmacokinetics of abacavir have not been studied in patients with moderate or severe hepatic impairment; therefore, ZIAGEN is contraindicated in these patients.
Pediatric Patients
The pharmacokinetics of abacavir have been studied after either single or repeat doses of ZIAGEN in 68 pediatric subjects. Following multiple-dose administration of ZIAGEN 8 mg/kg twice daily, steady-state AUC(0-12 hr) and Cmax were 9.8 ± 4.56 mcg•hr/mL and 3.71 ± 1.36 mcg/mL (mean ± SD), respectively [see Use in Specific Populations (8.4)]. In addition, to support dosing of ZIAGEN scored tablet (300 mg) for pediatric patients 14 kg to greater than 30 kg, analysis of actual and simulated pharmacokinetic data indicated comparable exposures are expected following administration of 300 mg scored tablet and the 8 mg/kg dosing regimen using oral solution. Geriatric Patients: The pharmacokinetics of ZIAGEN have not been studied in patients over 65 years of age. Gender: A population pharmacokinetic analysis in HIV-1-infected male (n = 304) and female (n = 67) subjects showed no gender differences in abacavir AUC normalized for lean body weight.
Race
There are no significant differences between blacks and Caucasians in abacavir pharmacokinetics.
Nonclinical Toxicology
Microbiology
Abacavir is a carbocyclic synthetic nucleoside analogue. Abacavir is converted by cellular enzymes to the active metabolite, carbovir triphosphate (CBV-TP), an analogue of deoxyguanosine-5′-triphosphate (dGTP). CBV-TP inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA. The lack of a 3′-OH group in the incorporated nucleotide analogue prevents the formation of the 5′ to 3′ phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated. CBV-TP is a weak inhibitor of cellular DNA polymerases α, β, and γ.
Antiviral Activity
The antiviral activity of abacavir against HIV-1 was evaluated against a T-cell tropic laboratory strain HIV-1IIIB in lymphoblastic cell lines, a monocyte/macrophage tropic laboratory strain HIV-1BaL in primary monocytes/macrophages, and clinical isolates in peripheral blood mononuclear cells. The concentration of drug necessary to effect viral replication by 50 percent (EC50) ranged from 3.7 to 5.8 μM (1 μM = 0.28 mcg/mL) and 0.07 to 1.0 μM against HIV-1IIIB and HIV-1BaL, respectively, and was 0.26 ± 0.18 μM against 8 clinical isolates. The EC50values of abacavir against different HIV-1 clades (A-G) ranged from 0.0015 to 1.05 μM, and against HIV-2 isolates, from 0.024 to 0.49 μM. The antiviral activity of abacavir in cell culture was not antagonized when combined with the nucleoside reverse transcriptase inhibitors (NRTIs) didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zalcitabine or zidovudine, the non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine, or the protease inhibitor (PI) amprenavir. Ribavirin (50 μM) had no effect on the anti–HIV-1 activity of abacavir in cell culture.
Resistance
HIV-1 isolates with reduced susceptibility to abacavir have been selected in cell culture and were also obtained from subjects treated with abacavir. Genotypic analysis of isolates selected in cell culture and recovered from abacavir-treated subjects demonstrated that amino acid substitutions K65R, L74V, Y115F, and M184V/I in RT contributed to abacavir resistance. In a trial of therapy-naive adults receiving ZIAGEN 600 mg once daily (n = 384) or 300 mg twice daily (n = 386), in a background regimen of lamivudine 300 mg once daily and efavirenz 600 mg once daily (CNA30021), the incidence of virologic failure at 48 weeks was similar between the 2 groups (11% in both arms). Genotypic (n = 38) and phenotypic analyses (n = 35) of virologic failure isolates from this trial showed that the RT substitutions that emerged during abacavir once-daily and twice-daily therapy were K65R, L74V, Y115F, and M184V/I. The substitution M184V/I was the most commonly observed substitution in virologic failure isolates from subjects receiving abacavir once daily (56%, 10/18) and twice daily (40%, 8/20).
Thirty-nine percent (7/18) of the isolates from subjects who experienced virologic failure in the abacavir once-daily arm had a greater than 2.5-fold decrease in abacavir susceptibility with a median-fold decrease of 1.3 (range: 0.5 to 11) compared with 29% (5/17) of the failure isolates in the twice-daily arm with a median-fold decrease of 0.92 (range: 0.7 to 13).
Cross-Resistance
Cross-resistance has been observed among NRTIs. Isolates containing abacavir resistance-associated substitutions, namely, K65R, L74V, Y115F, and M184V, exhibited cross-resistance to didanosine, emtricitabine, lamivudine, tenofovir, and zalcitabine in cell culture and in subjects. The K65R substitution can confer resistance to abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir, and zalcitabine; the L74V substitution can confer resistance to abacavir, didanosine, and zalcitabine; and the M184V substitution can confer resistance to abacavir, didanosine, emtricitabine, lamivudine, and zalcitabine. An increasing number of thymidine analogue mutations (TAMs: M41L, D67N, K70R, L210W, T215Y/F, K219E/R/H/Q/N) is associated with a progressive reduction in abacavir susceptibility.[1]
Clinical Studies
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Condition 2
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How Supplied
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Storage
There is limited information regarding Abacavir Storage in the drug label.
Images
Drug Images
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Package and Label Display Panel
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Patient Counseling Information
(Patient Counseling Information)
Precautions with Alcohol
Alcohol-Abacavir interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
Brand Names
There is limited information regarding Abacavir Brand Names in the drug label.
Look-Alike Drug Names
- (Paired Confused Name 1a) — (Paired Confused Name 1b)
- (Paired Confused Name 2a) — (Paired Confused Name 2b)
- (Paired Confused Name 3a) — (Paired Confused Name 3b)
Drug Shortage Status
Drug Shortage
Price
References
The contents of this FDA label are provided by the National Library of Medicine.
- ↑ 1.0 1.1 "ZIAGEN (ABACAVIR SULFATE) TABLET, FILM COATED ZIAGEN (ABACAVIR SULFATE) SOLUTION [VIIV HEALTHCARE COMPANY]". Retrieved 30 December 2013.