What the label lists and what reports show
Methadone side effects
Methadone's FDA label: “Most common adverse reactions are: lightheadedness, dizziness, sedation, nausea, vomiting, and sweating.” FAERS holds 45,988 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is drug dependence (5,946 reports).
- Generic listed
- Boxed warning
- DEA Schedule II
Check it at the source: the methadone FDA label on DailyMed (effective December 8, 2025, Epic Pharma, LLC); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions are: lightheadedness, dizziness, sedation, nausea, vomiting, and sweating.
From the label: adverse reactions, continuedThe following serious adverse reactions are described, or described in greater detail, in other sections: • Addiction, Abuse, and Misuse [see Warnings and Precautions (5.1) ]. • Life Threatening Respiratory Depression [see Warnings and Precautions (5.2)] • Interactions with Benzodiazepines and other CNS Depressants [see Warnings and Precautions (5.3) ] • QT Prolongation [see Warnings and Precautions (5.4)] • Neonatal Opioid Withdrawal Syndrome [see Warnings and Precautions (5.5) ] • Opioid-Induced Hyperalgesia and Allodynia [see Warnings and Precautions (5.8) ] • Serotonin Syndrome [see Warnings and Precautions (5.9) ] • Adrenal Insufficiency [see Warnings and Precautions (5.11) ] • Severe Hypotension [see Warnings and Precautions (5.12) ] • Gastrointestinal Adverse Reactions [see Warnings and Precautions (5.14) ] • Seizures [see Warnings and Precautions (5.15) ] • Withdrawal [see Warnings and Precautions (5.16) ] The following adverse reactions associated with the use of methadone were identified in clinical studies or postmarketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The major hazards of methadone are respiratory depression and, to a lesser degree, systemic hypotension. …
Source: FDA drug label, Epic Pharma, LLC, effective December 8, 2025 (SPL set 6da7501b-b881-4bc7-891a-74214a00a3ac), via openFDA; the full label on DailyMed
What do FAERS reports show?
45,988 reports list methadone among the medicines taken, each a report of something that happened, not proof the medicine caused it; 14,750 are coded as a death and 11,818 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 17 reactions below, 5 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Methadone: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions