ABACAVIR SULFATE
| ABACAVIR SULFATe (a-ba'ca-vir) Ziagen Classifications: antiviral agent; antiretroviral agent; nucleoside reverse transcriptase inhibitor (nrti); Therapeutic: antiviral; antiretroviral (nrti) Prototype: Lamivudine Pregnancy Category: C |
Availability
300 mg tablets; 20 mg/mL oral solution
Action
Abacavir is a synthetic nucleoside analogue with inhibitory activity against HIV. It inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural DNA nucleoside and by incorporation into viral DNA.
Therapeutic Effect
Abacavir prevents the formation of viral DNA replication. Therefore the viral load decreases as measured by an increased CD4 lymphocyte cell count and suppression of HIV RNA, indicated by decreased HIV RNA copies, in HIV-positive individuals with little or no exposure to zidovudine (AZT).
Uses
Treatment of HIV infection in combination with other antiretroviral agents.
Contraindications
Hypersensitivity to abacavir (fatal rechallenge reactions reported); lactic acidosis; creatinine clearance of <50 mL/min; severe hepatomegaly; pregnancy (category C); lactation.
Cautious Use
Prior resistance to another nucleoside reverse transcriptase inhibitor (NRTI); hepatic dysfunction; older adults.
Route & Dosage
| HIV Infection Adult: PO 300 mg b.i.d. Child (3 mo–16 y): PO 8 mg/kg b.i.d. (max: 300 mg b.i.d.) Hepatic Impairment Mild (Child-Pugh score 5–6): 200 mg b.i.d. |
Administration
Oral- Tablets & oral solution are interchangeable on a mg-for-mg basis.
- Store tablets and liquid at 20°–25° C (68°–77° F). Liquid may be refrigerated.
Adverse Effects (≥1%)
Body as a Whole: Hypersensitivity reactions (including fever, skin rash, fatigue, nausea, vomiting, diarrhea, abdominal pain); malaise; lethargy; myalgia; arthralgia; paresthesia; edema; shortness of breath. CNS: Insomnia, headache, fever. CV: Hypotension (associated with hypersensitivity reaction). GI: Hepatomegaly with steatosis, nausea, vomiting, diarrhea, anorexia, pancreatitis, increased GGT, increased liver function tests. Skin: Rash. Other: Lactic acidosis, renal insufficiency.Interactions
Drug: Alcohol may increase abacavir blood levels.Pharmacokinetics
Absorption: Rapidly absorbed, 83% bioavailable. Distribution: Distributes into extravascular space and erythrocytes; 50% protein bound. Metabolism: Metabolized by alcohol dehydrogenase and glucuronyl transferase to inactive metabolites. Elimination: 84% in urine, primarily as inactive metabolites; 16% excreted in feces. Half-Life: 1.5 h.Nursing Implications
Assessment & Drug Effects
- Monitor for S&S of hypersensitivity: fever, skin rash, fatigue, GI distress (nausea, vomiting, diarrhea, abdominal pain). Withhold drug immediately & notify physician if hypersensitivity develops.
- Lab tests: Periodically monitor liver function, BUN and creatinine, CBC with differential, triglyceride levels, and blood glucose, especially in diabetics.
- Withhold drug & notify physician for S&S of acidosis, hepatotoxicity, or renal insufficiency.
Patient & Family Education
- Take drug exactly as prescribed at indicated times. Missed dose: Take immediately, then resume dosing schedule. Do not double a dose.
- Withhold drug immediately & notify physician at first sign of hypersensitivity reaction (see Assessment & Drug Effects).
- Carry Warning Card provided with drug at all times.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug