For short-acting opioids like heroin or oxycodone, the worst of withdrawal is usually over in 4 to 7 days. For long-acting opioids like methadone, the timeline stretches to 14 to 21 days. For fentanyl, the picture is more complicated — short half-life but stored in body fat — and the timeline often runs in waves for 10 to 14 days. Then a quieter post-acute phase that can persist for 6 to 12 months. Those are the four numbers most families want, but the real answer depends on which opioid, what dose, how long, and what medical help is on the table.
This guide walks through the typical opioid withdrawal timeline, the variables that shift it, and the safe paths through. Updated April 2026. Medically reviewed by the RehabPulse editorial team. This is informational only and does not replace medical care — anyone in active withdrawal should call the SAMHSA national helpline at 1-800-662-HELP (4357) for immediate guidance.
The 60-second answer — by opioid
The acute phase timeline depends mostly on the half-life of the specific opioid:
- Heroin, oxycodone, hydrocodone (short-acting). Onset 8 to 24 hours after last dose. Peak at 36 to 72 hours. Acute symptoms resolve in 4 to 7 days.
- Fentanyl (potent but technically short-acting). Onset 8 to 24 hours. Peak at 36 to 72 hours. Acute symptoms in waves for 7 to 14 days because illicit fentanyl is often cut with long-acting analogs that store in fat tissue and leach back out. See our fentanyl withdrawal symptoms guide for the full picture.
- Methadone (long-acting). Onset 24 to 48 hours. Peak at day 4 to 7. Acute symptoms over 14 to 21 days. Subtler day-to-day, longer overall.
- Buprenorphine (Suboxone, partial agonist). Onset 24 to 72 hours. Peak around day 3 to 7. Acute symptoms over 10 to 14 days. Generally milder than full agonists due to the ceiling effect.
The post-acute phase (PAWS — post-acute withdrawal syndrome) is similar across opioids: mood swings, sleep fragmentation, low energy, intermittent cravings, fatigue. It typically starts about a week after the last dose, peaks around weeks 2 to 6, and gradually fades over 3 to 12 months.
Opioid withdrawal is rarely directly fatal (unlike alcohol or benzodiazepine withdrawal). But it is intensely uncomfortable, with a much higher relapse rate when attempted alone. The single largest cause of death during opioid withdrawal is overdose on relapse — tolerance drops sharply within days, and the dose someone previously used can stop their breathing on the second or third attempt.
Why timing varies — half-life and the body's storage
Two pharmacological facts explain most of the differences in opioid withdrawal timelines.
Half-life. The time it takes the body to clear half of a given dose. Heroin's half-life is about 6 minutes (the drug itself), with active metabolites lasting longer. Oxycodone's is 3 to 5 hours. Methadone's is 24 to 36 hours. A long half-life means the brain has more time to slowly notice the drop, producing a slower-onset, longer-tail withdrawal. A short half-life means a faster, sharper start.
Fat solubility. Opioids that store in fat tissue (especially fentanyl analogs like carfentanil and acetylfentanyl) can leach back into the bloodstream for days after last use, producing wave after wave of returning symptoms. Most people don't know: this is why fentanyl withdrawal, despite the drug's nominally short half-life, often feels longer than heroin withdrawal at the same severity. The drug is technically clearing but functionally still present at low levels.
Dose and duration. Higher daily doses and longer use histories both deepen the brain's adaptation to opioids, which slows the rebalance during withdrawal. Six months of moderate use produces a milder, shorter withdrawal than ten years of high-dose use.
The typical opioid withdrawal timeline, hour by hour
This is the standard timeline for short-acting opioids (heroin, oxycodone, hydrocodone) from a daily heavy user, drawn from clinical observations and the SAMHSA opioid treatment guidance:
Hours 0 to 8. No noticeable symptoms for most people. Heavy daily users may notice mild anxiety, yawning, or restlessness by hour 6 to 8.
Hours 8 to 24. Early symptoms arrive: runny nose, watery eyes, sweating, yawning, dilated pupils, mild muscle aches, anxiety, restlessness. Sleep is already disrupted. By hour 18, most people know something is wrong.
Hours 24 to 72 (peak window). Worst of the physical storm. Severe muscle and bone aches, abdominal cramps, diarrhea, vomiting, drenching sweats followed by chills, racing heart, hypertension, persistent crawling-skin sensation. Anxiety becomes overwhelming. Sleep is essentially absent. Craving is constant and physical. This is the window where most relapses happen — the body is at peak suffering and the brain knows one dose will end it within minutes.
Days 4 to 7. Acute symptoms begin to ease. Muscle aches fade. Diarrhea and cramping calm. Sleep returns in fragments. Energy is still low and mood is unstable, but the worst is over.
Week 2 onward. Most physical symptoms resolve. Sleep gradually consolidates. Appetite returns. PAWS begins.
For methadone and other long-acting opioids, shift each milestone roughly 24-48 hours later and add 7-10 days to the acute phase total. The peak is less sharp but lasts longer.
What makes opioid withdrawal worse or longer
Four variables explain most of the variation between two people withdrawing from the same opioid at the same dose:
Duration of use. A 2-year history produces a milder withdrawal than a 10-year history at the same daily dose. The brain's tolerance and counter-regulation systems deepen over years.
Daily dose. Higher daily totals mean more receptor saturation and a larger rebound when the opioid disappears.
Polysubstance use. Daily benzodiazepine or alcohol use alongside opioids extends and intensifies the withdrawal substantially. The withdrawal from each substance interacts with the others.
Co-occurring health conditions. Chronic pain, severe anxiety or depression, sleep disorders, and major medical illness all extend the timeline. Picture a 50-year-old with chronic back pain, untreated depression, and a 7-year opioid use history — the same withdrawal that a healthier 30-year-old finishes in 6 days might run 14 days for him without medication support.
The fifth variable is access to medication-assisted treatment (MAT). Buprenorphine or methadone, started in the right window, transforms the experience from "untreatable suffering" into "uncomfortable few days." More on that below.
Post-acute withdrawal — the part nobody warned you about
PAWS is the cluster of symptoms that linger after the body has technically cleared the opioid: low mood, anxiety in waves, sleep that breaks into pieces, brain fog, fatigue that hits without warning, irritability, and cravings that surge at random times.
For opioid users, PAWS is real and well-documented. Brain imaging studies show that opioid receptor density and dopamine system function take months to normalize after extended use. Picture a person on day 47 of opioid abstinence who has felt fine for two weeks and suddenly wakes up at 4 a.m. with a heart-pounding craving and no obvious trigger. That is not failure. That is a PAWS wave. The rule of thumb in early recovery groups is "play the tape forward" — riding the wave through usually leaves you on day 48 still sober. Reaching for an opioid resets the entire clock and, more dangerously, reintroduces fatal overdose risk because tolerance is gone.
Most people find PAWS waves come less often and less intensely every month. By month 6, they are usually rare. By month 12, they are typically a few times a year, often around stress or unrelated illnesses.
The other long-tail challenge is anhedonia — the inability to feel pleasure from normal activities. Caused by the dopamine system slowly recovering after years of artificial opioid stimulation, anhedonia often persists 3 to 9 months. Most people recovering from long-term opioid use describe this as the single hardest part of long-term recovery. It feels like grey. It is, biologically, the brain's reward system rebuilding from the inside. It does pass.
How to get through opioid withdrawal safely
There are three honest options, and the gap between them is wider than for alcohol withdrawal.
Medical detox with MAT (the strongly recommended path). Buprenorphine (Suboxone) or methadone, started at an appropriate window during withdrawal, reduces symptoms by 70 to 90% and dramatically lowers relapse rates. For fentanyl specifically, the 2025 standard is micro-induction onto buprenorphine over 24 to 72 hours to avoid precipitated withdrawal. Our suboxone vs methadone guide covers the comparison in detail. Both medications have decades of safety data and cut all-cause mortality in opioid use disorder by roughly 50% during treatment, per the NIDA medications research review.
Symptomatic detox without MAT. Clonidine for autonomic symptoms (sweating, blood pressure, anxiety), loperamide for diarrhea, anti-nausea medication, sleep aids. Works adequately for short-term, low-dose users but leaves most of the suffering in place for chronic users. Relapse rates within 30 days are 80 to 90% for chronic opioid users on this path, versus 30 to 50% with MAT. The data is overwhelming.
Quitting cold turkey at home. For someone whose use is recent and low-dose (a few weeks of post-surgical opioid prescription, for example), 4 to 7 uncomfortable days at home is usually safe with hydration, anti-nausea over-the-counter medication, and a sober support person. For chronic daily users, this is the most dangerous option. Most opioid-related deaths happen during or just after a home cold-turkey attempt, when the person relapses with a now-fatal dose at lowered tolerance.
Three rules for any opioid withdrawal attempt, regardless of method:
- Naloxone (Narcan) in the room. Two doses minimum. Available over the counter at most pharmacies in 2026, free at many county health departments. If relapse happens, it can stop a fatal overdose in about 2 minutes.
- A sober person checking in regularly. Aspiration during sleep after vomiting is a real risk. Dehydration from 48-72 hours of vomiting and diarrhea can drop blood pressure dangerously.
- A plan for the relapse window. Statistically, in unmanaged opioid withdrawal, relapse is more likely than not. The plan must include a sharply lower test dose if it happens, naloxone immediately accessible, and a phone call to a clinician or helpline within 24 hours to restart medical detox.
For a comparison of treatment levels (inpatient detox vs outpatient MAT), our outpatient vs inpatient rehab guide walks through which fits which situation. For the financial side, the how much does rehab cost guide covers insurance and out-of-pocket math.
For tracking the recovery weeks after acute withdrawal ends, a day-by-day sobriety counter helps make the invisible progress visible — most people see clear improvement in sleep, mood, and energy by week 6, but it is much easier to see in a log than in memory.
Other resources on RehabPulse:
Frequently asked questions
How long does opioid withdrawal last for heroin users? Acute symptoms typically last 4 to 7 days, with the worst at hours 48 to 72. Post-acute symptoms (mood, sleep, cravings) can persist for 3 to 12 months and gradually fade. Buprenorphine or methadone started during the early window reduces both acute and post-acute severity substantially.
How long does opioid withdrawal last for fentanyl users? Acute symptoms can last 7 to 14 days because illicit fentanyl is often cut with long-acting analogs that store in fat tissue and leach back out. The peak is around hours 36 to 72, similar to heroin, but returning waves can persist for two weeks before fully resolving. Medical detox with micro-induction onto buprenorphine is the current standard.
How long does methadone withdrawal last? Methadone withdrawal starts later (24-48 hours after last dose) and lasts longer (14-21 days acute) than withdrawal from short-acting opioids. Symptoms are usually subtler day to day but more persistent. Tapering methadone gradually under medical supervision is far safer and more comfortable than abrupt cessation.
Can opioid withdrawal kill you? Direct deaths from withdrawal symptoms are rare (unlike alcohol or benzodiazepine withdrawal, which can be directly fatal). The major indirect risks are dehydration from prolonged vomiting and diarrhea, aspiration during sleep, and — most commonly — overdose on relapse because tolerance drops sharply within days. Naloxone in the room is essential during any opioid withdrawal attempt.
What is the fastest way to stop opioid withdrawal symptoms? Medical induction onto buprenorphine (Suboxone) or methadone at a clinic or hospital is the fastest evidence-based way. Both work within hours of the first correct dose. In 2026, most U.S. hospital emergency departments can start buprenorphine on the spot — say "I am in opioid withdrawal and want to start buprenorphine" at triage.
