Methadone and Abacavir: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jun 30, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Methadone
Abacavir
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
If you take methadone and start abacavir (an HIV medicine), the abacavir can speed up how fast your body clears the methadone. That means the methadone level in your blood may drop a bit, so it might not work as well as it did before.
The main thing to watch for is early signs of methadone withdrawal, like feeling anxious, achy, sweaty, having a runny nose, chills, or an upset stomach. This is very manageable. Your care team can watch how you feel and, if needed, adjust your methadone dose to keep you comfortable. Please don't change any doses on your own, just let your prescriber or pharmacist know how you're feeling.
Effect: Abacavir increases oral methadone clearance (~22%; 90% CI 6% to 42%), reducing methadone exposure. Neither agent is relevant here as a prodrug; methadone effect is directly reduced.
Mechanism: Induction of CYP3A4-mediated methadone metabolism.
- Direction: Reduced methadone effect, risk of opioid withdrawal.
- Evidence: Established (clinical study in 11 methadone-maintained HIV patients).
- Severity: Major.
- Management: Monitor for withdrawal signs/symptoms after initiating abacavir; individualize and adjust methadone dose. A small number of patients may need an increased methadone dose.
What happens
Increased methadone plasma clearance and reduced methadone exposure
Interaction Deep Dive
Among 11 HIV-positive patients on methadone-maintenance therapy (daily doses of 40 mg and 90 mg), giving abacavir 600 mg concurrently (double the recommended amount) raised oral methadone clearance by 22% (90% confidence interval, 6% to 42%)2. Patients maintained on methadone who begin abacavir should be watched for indications of methadone withdrawal, with the methadone dose modified as needed 34. A small subset of patients may need higher methadone doses 152.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of methadone
How to manage this interaction
Good news: this is something your care team handles routinely. If abacavir is added to your methadone therapy, they will watch for signs of methadone withdrawal and can adjust your methadone dose to keep you stable and comfortable.
- Keep taking both exactly as prescribed unless your provider tells you otherwise.
- Report withdrawal symptoms such as anxiety, muscle aches, sweating, chills, runny nose, or nausea.
- Your methadone dose may need to be adjusted and individualized by your team; a small number of people need a slightly higher dose.
- Ask your pharmacist or prescriber before making any changes.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
Common questions
Can I take Methadone and Abacavir together?
Abacavir can lower your methadone levels and trigger withdrawal symptoms, so tell your care team if you feel achy, anxious, sweaty, or unwell; they can adjust your methadone dose to keep you comfortable. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Methadone and Abacavir interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Methadone and Abacavir interaction managed?
Good news: this is something your care team handles routinely. If abacavir is added to your methadone therapy, they will watch for signs of methadone withdrawal and can adjust your methadone dose to keep you stable and comfortable. Keep taking both exactly as prescribed unless your provider tells you otherwise. Report withdrawal symptoms such as anxiety, muscle aches, sweating, chills, runny nose,… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Methadone or Abacavir need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (5)
- Product Information: TRIUMEQ oral tablets, abacavir, dolutegravir, lamivudine oral tablets. ViiV Healthcare (per FDA), Durham, NC, 2023. DailyMed
- Product Information: ZIAGEN(R) oral tablets, oral solution, abacavir oral tablets, oral solution. ViiV Healthcare (per FDA), Research Triangle Park, NC, 2020. DailyMed
- Product Information: DOLOPHINE(R) oral tablets, methadone HCl oral tablets. West-Ward Pharmaceuticals Corp (per FDA), Eatontown, NJ, 2019. DailyMed
- Product Information: Methadone HCl injection, methadone HCl injection. Mylan Institutional LLC (per FDA), Morgantown, WV, 2023. DailyMed
- Product Information: TRIUMEQ PD oral tablets for suspension, abacavir, dolutegravir, lamivudine oral tablets. ViiV Healthcare (per FDA), Durham, NC, 2023. DailyMed
Keep reading about Methadone
Keep reading about Abacavir
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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