abacavir (Rx)

Brand and Other Names:Ziagen
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

oral solution

  • 20mg/mL

tablet

  • 300mg

HIV Infection

Indicated for treatment of HIV infection in combination with other antiretroviral agents

300 mg PO q12hr, OR

600 mg PO qDay

Dosage Modifications

Renal impairment: No dosage adjustment required

Hepatic impairment

  • Mild (Child-Pugh A); adults and adolescents aged ≥16 years: Reduce dose to 200 mg q12hr (use oral solution)
  • Moderate-to severe (Child-Pugh B or C): Contraindicated

Dosage Forms & Strengths

oral solution

  • 20mg/mL

tablet

  • 300mg

HIV Infection

Indicated for treatment of HIV infection in combination with other antiretroviral agents

Neonates/infants <3 months: Safety and efficacy not established

Oral solution

  • ≥3 months: 8 mg/kg PO q12hr or 16 mg/kg/day; not to exceed 600 mg/day  

Tablet

  • Available as a scored tablet; if unable to reliably swallow tablets, prescribe the oral solution
  • ≥14 kg to <20 kg: 150 mg PO q12hr, OR 300 mg qDay
  • ≥20 to <25 kg: 150 mg AM and 300 mg PM, OR 450 mg qDay
  • ≥25 kg: 300 mg PO q12hr, OR 600 mg PO qDay in combination with other antiretroviral agents

Dosage Modifications

Renal impairment: No dosage adjustment required

Hepatic impairment

  • Mild (Child-Pugh A); adults and adolescents aged ≥16 years: Reduce dose to 200 mg q12hr (use oral solution)
  • Moderate-to severe (Child-Pugh B or C): Contraindicated

Dosing Considerations

Once daily dosing: NIH pediatric HIV guidelines (March, 2016) recommend initiation of therapy with once-daily dosing in children who can be treated with the tablet formulation

Twice daily dosing: Use twice daily dosing in infants and young children initiating therapy with liquid formulations; consider switching to once-daily dosing after 6 months when viral load is undetectable and CD4 cell count is stable

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Interactions

Interaction Checker

and abacavir

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 

            Contraindicated (1)

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              abacavir, elvitegravir/cobicistat/emtricitabine/tenofovir DF. Other (see comment). Contraindicated. Comment: Elvitegravir/cobicistat/emtricitabine/tenofovir is a complete regimen for HIV and should not be administered with other antiretrovirals.

            Serious - Use Alternative (6)

            • betibeglogene autotemcel

              abacavir, betibeglogene autotemcel. Other (see comment). Avoid or Use Alternate Drug. Comment: Do not take antiretroviral medications for at least 1 month before mobilization or expected duration for elimination of the medications, and until all cycles of apheresis are completed. Antiretroviral medications may interfere with manufacturing of apheresed cells.

            • cabotegravir

              abacavir, cabotegravir. Other (see comment). Avoid or Use Alternate Drug. Comment: Cabotegravir plus rilpivirine is a complete regimen. Coadministration with other antiretroviral medications for treating HIV-1 infection is not recommended.

            • elivaldogene autotemcel

              elivaldogene autotemcel, abacavir. Either decreases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Patients should not take antiretroviral medications for at least 1 month before initiating medications for stem cell mobilization, for the duration of the medications? elimination, and until all cycles of apheresis are completed.

            • ganciclovir

              ganciclovir, abacavir. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Increased risk of hematologic toxicity.

            • ribavirin

              ribavirin increases toxicity of abacavir by Other (see comment). Avoid or Use Alternate Drug. Comment: Increased risk of lactic acidosis and hepatic decompensation.

            • valganciclovir

              valganciclovir, abacavir. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Increased risk of hematologic toxicity.

            Monitor Closely (21)

            • atazanavir

              atazanavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • cabozantinib

              abacavir will increase the level or effect of cabozantinib by Other (see comment). Use Caution/Monitor. MRP2 inhibitors increase cabozantinib toxicity

            • didanosine

              abacavir and didanosine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • efavirenz

              abacavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • emtricitabine

              abacavir and emtricitabine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • enfuvirtide

              abacavir and enfuvirtide both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • fosamprenavir

              fosamprenavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • indinavir

              indinavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • lamivudine

              abacavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • methadone

              abacavir will decrease the level or effect of methadone by unknown mechanism. Use Caution/Monitor. Monitor for opioid withdrawal symptoms.

            • nelfinavir

              nelfinavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • nevirapine

              abacavir and nevirapine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • orlistat

              orlistat will decrease the level or effect of abacavir by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Loss of virological control reported in HIV-infected patients taking orlistat concomitantly. Exact mechanism is unclear, but may include a drug-drug interaction that inhibits systemic absorption of the antiretroviral drug. Monitor HIV RNA levels frequently and if increased HIV viral load confirmed, discontinue orlistat.

            • riociguat

              abacavir will increase the level or effect of riociguat by unknown mechanism. Modify Therapy/Monitor Closely. Riociguat dose reduction may be necessary

            • ritonavir

              ritonavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • saquinavir

              saquinavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • stavudine

              abacavir and stavudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • tenofovir DF

              abacavir and tenofovir DF both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            • tipranavir

              tipranavir and abacavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

              tipranavir decreases levels of abacavir by unspecified interaction mechanism. Use Caution/Monitor.

            • ublituximab

              ublituximab decreases effects of abacavir by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely.

            • zidovudine

              abacavir and zidovudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

            Minor (1)

            • ethanol

              ethanol increases levels of abacavir by decreasing metabolism. Minor/Significance Unknown. Interaction usually not clinically significant.

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            Adverse Effects

            >10%

            Nausea (17-19%)

            Headache (9-13%)

            Malaise/fatigue (12%)

            Nausea & vomiting (10%)

            1-10%

            Hypersensitivity reaction (2-8%)

            Diarrhea (5-7%)

            Musculoskeletal pain (5-7%)

            Hypertriglyceridemia (6%)

            Hepatic: AST increased (6%)

            Depression (4-6%)

            Fever/chills (3-6%)

            Viral respiratory infections (5%)

            Ear/nose/throat infections (4-5%)

            Rash (4-5%)

            Anxiety (3-5%)

            Thrombocytopenia (1%)

            <1%

            Anaphylactoid reaction

            Pulmonary hypertension

            Erythema multiforme

            Redistribution/accumulation of body fat

            Stevens-Johnson syndrome

            Toxic epidermal necrolysis

            Pancreatitis

            GGT increased

            Hepatic steatosis

            Heptaomegaly

            Hepatotoxicity

            Lactic acidosis

            MI

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            Warnings

            Black Box Warnings

            Hypersensitivity reactions

            • Severe and sometimes fatal hypersensitivity reaction, with multiple organ involvement, have occurred
            • Patients who carry the HLA-B*5701 allele are at a higher risk of a hypersensitivity reaction; although, hypersensitivity reactions have occurred in patients who do not carry the HLA-B*5701 allele
            • Contraindicated with history of prior hypersensitivity reaction to abacavir and in patients who are HLA-B*5701-positive
            • All patients should be screened for the HLA-B*5701 allele before initiating or reinitiating abacavir, unless patients have a previously documented HLA-B*5701 allele assessment
            • If hypersensitivity is suspected, discontinue abacavir immediately, regardless of HLA-B*5701 status and even when other diagnoses are possible
            • Following a hypersensitivity reaction, never restart therapy or any other abacavir-containing product because more severe symptoms, including death can occur within hours; similar severe reactions have also occurred rarely following the reintroduction of abacavir-containing products in patients who have no history of abacavir hypersensitivity

            Contraindications

            Prior hypersensitivity reaction to abacavir

            Presence of HLA-B*5701 allele

            Moderate or severe hepatic impairment

            Cautions

            Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, reported with nucleoside analogs, including abacavir; a majority of these cases have been in women; female gender and obesity may be risk factors; suspend dosing in those who develop clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity, which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations

            Immune reconstitution syndrome reported with combination ART; during the initial treatment phase, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (eg, Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia [PCP], or tuberculosis); autoimmune disorders (eg, Graves disease, polymyositis, and Guillain-Barré syndrome) have also been reported

            Use has been associated with increased risk of myocardial infarction in observational studies, but not in a meta-analysis of 26 randomized trials; caution with risks for coronary heart disease and minimizing modifiable risk factors, including smoking, hypertension, and hyperlipidemia, prior to use

            Hypersensitivity

            • Before starting therapy, review medical history for prior exposure to any abacavir containing product
            • Increased risk of serious or fatal hypersensitivity reactions; patients with human leukocyte antigen allele, HLA-B*5701 are at a higher risk; do not restart abacavir following hypersensitive reaction; may cause hypotension, multiorgan failure, and/or death (see Contraindications and Black Box Warnings)
            • If a hypersensitivity reaction is ruled out, patients may restart therapy; rarely, patients who have stopped abacavir for reasons other than symptoms of hypersensitivity have also experienced life-threatening reactions within hours of reinitiating abacavir therapy; reintroduction to drug or any other abacavir-containing product recommended only if medical care can be readily accessed
            • A Medication Guide and Warning Card that provide information about recognition of hypersensitivity reactions should be dispensed with each new prescription and refill

            Drug interaction overview

            • Methadone
              • In a trial of 11 HIV-1-infected subjects receiving methadone-maintenance therapy with abacavir 600 mg BID (twice the currently recommended dose), PO methadone clearance increased
              • 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
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            Pregnancy & Lactation

            Pregnancy

            Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263

            Available data from the APR show no difference in the overall risk of birth defects for abacavir compared with the background rate for birth defects of 2.7% in the Metropolitan Atlanta Congenital Defects Program (MACDP) reference population

            In animal reproduction studies, oral administration of abacavir to pregnant rats during organogenesis resulted in fetal malformations and other embryonic and fetal toxicities at exposures 35 times the human exposure (AUC) at the recommended clinical daily dose; however, no adverse developmental effects were observed following oral administration of abacavir to pregnant rabbits during organogenesis, at exposures approximately 9 times the human exposure (AUC) at the recommended clinical dose

            Lactation

            Abacavir is present in human milk; there is no information on effects of abacavir on breastfed infant or effects of drug on milk production; because of potential for (1) HIV-1 transmission (in HIV-negative infants), (2) developing viral resistance (in HIV- positive infants), and (3) serious adverse reactions in breastfed infant, instruct mothers not to breastfeed if they are receiving abacavir

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Guanosine analog that inhibits HIV-1 reverse transcriptase by competing with dGTP as substrate, which in turn inhibits viral replication

            Absorption

            Rapid and extensive PO absorption

            Bioavailability: 83%

            Peak plasma concentration: 3 mcg/mL (300 mg); 4.26 mcg/mL (600 mg)

            AUC: 6.02 mcg·h/mL (300 mg); 11.95 mcg·h/mL (600 mg)

            Distribution

            Vd: 0.86 L/kg

            Protein bound: 50%

            Metabolism

            Hepatic via alcohol dehydrogenase and glucuronyl transferase to inactive carboxylate and glucuronide metabolites

            Elimination

            Half-life: 1.5 hr

            Peak plasma time: 0.7-1.7 hr

            Excretion: Urine (80%); feces (16%)

            Pharmacogenomics

            Patients who carry the HLA-B*5701 allele are at high risk for experiencing a hypersensitivity reaction

            Prior to initiating therapy with abacavir, screening for the HLA-B*5701 allele is recommended

            For HLA-B*5701-positive patients, treatment with an abacavir-containing regimen is not recommended

            Genetic testing laboratories

            • The following companies provide genetic testing for HLA variants
            • Kashi Clinical Laboratories (www.kashilab.com)
            • LabCorp (http://www.labcorp.com)
            • Specialty Laboratories (http://www.specialtylabs.com)
            • Quest (http://www.questdialgnotics.com)
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            Administration

            Oral Administration

            May take with or without food

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            Ziagen oral
            -
            300 mg tablet
            Ziagen oral
            -
            20 mg/mL solution
            abacavir oral
            -
            300 mg tablet
            abacavir oral
            -
            300 mg tablet
            abacavir oral
            -
            300 mg tablet
            abacavir oral
            -
            20 mg/mL solution
            abacavir oral
            -
            300 mg tablet
            abacavir oral
            -
            300 mg tablet
            abacavir oral
            -
            300 mg tablet

            Copyright © 2010 First DataBank, Inc.

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.