Abacavir is an NRTI (nucleoside/nucleotide reverse-transcriptase inhibitor) used to treat HIV-1. It is always taken in combination with other HIV medicines—never by itself. When taken correctly, it lowers the amount of virus in the blood, raises CD4 (immune strength), and reduces illness flares.
Biggest caution: People with the HLA-B*5701 gene can have a serious, potentially fatal allergy (hypersensitivity). Get this blood test before starting. If a hypersensitivity reaction ever occurs, never take abacavir again.
HIV-1 treatment in adults and in children ≥ 3 months, always with other antiretrovirals.
Not for use as monotherapy.
❌ Not used for HBV (hepatitis B) treatment.
HIV copies itself by turning its RNA into DNA using an enzyme called reverse transcriptase.
Think of “transcription” as making a copy. HIV does it in “reverse” (RNA → DNA).
In the body, abacavir becomes carbovir-triphosphate (CBV-TP), a “wrong brick” that gets inserted into the new viral DNA chain and halts the chain, stopping HIV from copying itself.
Forms: 300 mg tablets; 20 mg/mL oral solution.
Adults: 300 mg twice daily or 600 mg once daily (with other HIV meds).
Children (≥ 3 months): total 16 mg/kg/day (once daily or divided twice daily), max 600 mg/day.
Common fixed-dose combos:
Abacavir/lamivudine (ABC/3TC)
Abacavir/dolutegravir/lamivudine (ABC/DTG/3TC)
Can be taken with or without food.
Hypersensitivity can be severe. Test HLA-B*5701 before starting.
If you develop symptoms from any 2 of these 5 groups at the same time, stop immediately and contact a clinician:
Fever
Rash
Nausea/vomiting/abdominal pain/diarrhea
Extreme fatigue/feeling very unwell/aches
Shortness of breath/cough/sore throat
If hypersensitivity is suspected or confirmed, never restart abacavir or any abacavir-containing product.
Liver disease
Child-Pugh A (mild): 200 mg twice daily (measure with solution for accuracy).
Child-Pugh B or C: Contraindicated (do not use).
Kidney disease: Usually no dose change needed.
Pregnancy: Can be used based on current data; consider enrolling in a pregnancy registry.
Breastfeeding: Avoid—HIV can transmit via breast milk.
Older adults: Use extra caution (liver/kidney/heart risks).
HLA-B*5701 gene test (mandatory).
Baseline labs: CBC, AST/ALT, triglycerides, amylase, CD4, HIV RNA (viral load).
🚫 Do not use if: prior abacavir hypersensitivity, HLA-B*5701 positive, or moderate/severe liver disease.
Common: Nausea, diarrhea/abdominal pain, headache, fatigue, insomnia, poor appetite, skin rash.
Serious (urgent):
Hypersensitivity (often within first 6 weeks): any 2 of the 5 symptom groups above → stop now and never restart.
Lactic acidosis & liver injury: right-upper belly pain, jaundice, profound weakness, rapid breathing → urgent care.
Heart risk: Some observational studies suggest increased MI risk; trials are mixed. Discuss alternatives if you have high cardiac risk.
Alcohol (ethanol): Can increase abacavir levels → best to limit alcohol.
Methadone: A few people may need higher methadone doses.
Tipranavir/ritonavir: May lower abacavir levels (↑ glucuronidation).
Orlistat: May reduce absorption.
Gene therapy (betibeglogene/elivaldogene): Can interfere with apheresis/transduction—hold abacavir ahead of time.
Cladribine: Avoid.
Cabozantinib: Levels may increase (MRP2-related) → monitor/adjust.
Note: Do not co-give lamivudine solution with abacavir solution (tablet + tablet is fine).
Routine: Same time daily; with or without food.
Missed dose: Take when remembered; if close to next dose, skip the missed one. Do not double.
If you stop: Do not restart without medical advice—restarting can trigger severe hypersensitivity.
Storage: Room temperature, dry, away from light. Solution can be refrigerated but do not freeze.
Warning Card: Keep the abacavir Warning Card with you at all times.
After baseline: CBC, AST/ALT, lipids/triglycerides, amylase, CD4, viral load at 3–6 months, then as needed.
Check promptly if symptoms suggest liver injury or lactic acidosis.
Watch for fat redistribution (lipodystrophy).
HIV care works best with a team (clinician, nurse, pharmacist, counselor/social worker, lab).
Once-daily regimens are often easier to remember.
Use SMS/alarms/pillboxes—whatever keeps you on track.
If substance use, depression, or low support is an issue, counseling/CBT/DOT can help a lot
“Abacavir treats HBV.” → False. It’s for HIV.
“Abacavir cures HIV.” → False. It controls HIV; it doesn’t cure it.
“You can retry abacavir after an allergy.” → Absolutely not. Never restart.
Any 2 of the 5 hypersensitivity symptom groups at the same time.
Shortness of breath/chest pain, sudden sweating/vomiting, or pain in arm/jaw/neck.
Jaundice, right-upper belly pain, profound weakness/drowsiness, rapid breathing.
Abacavir is an NRTI for HIV-1 that works only in combination with other meds—and not for HBV. Test HLA-B*5701 before starting, and if you ever have a hypersensitivity reaction, never take it again—keep your Warning Card with you. Take doses regularly (no double doses if missed), get viral load/CD4 and liver tests on follow-up, and discuss any new meds or alcohol with your clinician. If fever + rash / tummy problems / breathing issues (any two groups together) appear, stop the drug and get help immediately. Used correctly, abacavir-based regimens suppress HIV and help you live your daily life more normally.
Disclaimer: This handout is for information and education only. It is not medical advice and isn’t a substitute for care from your clinician. Always consult your clinician before starting, stopping, or changing any medicine. For urgent symptoms, go to the nearest emergency department or call local emergency services.