The Opioid Withdrawal Timeline

This page maps each stage of withdrawal and explains why methadone follows a slower clock. It also covers the two ways withdrawal turns fatal, dehydration and overdose after tolerance drops, and what medically monitored withdrawal changes.

Key Takeaways

• Withdrawal from short-acting opioids such as heroin and oxycodone typically begins within 12 hours of a missed dose, peaks at 36 to 72 hours and tapers off over the following 4 to 7 days (Kosten and Baxter, 2019).
• Methadone withdrawal starts later, usually within 30 hours of the last dose, and SAMHSA reports that it may last 14 to 21 days.
• Opioid withdrawal is generally not fatal, but poorly managed dehydration from vomiting and diarrhea has caused deaths.
• Most opioid overdose deaths occur in people who have just detoxed, because withdrawal lowers tolerance, according to MedlinePlus.
• Anxiety, low mood and poor sleep can last for weeks or months after the acute phase, according to SAMHSA.

What is opioid withdrawal?

Opioid withdrawal is the set of physical and emotional symptoms that appears when a person whose body has adapted to opioids stops taking them or cuts back sharply. Many people call it being dope sick. The symptoms follow a typical timeline of onset, peak and taper.

Opioids include heroin, fentanyl, methadone and prescription painkillers such as oxycodone and hydrocodone. With regular use, the brain and body adjust to the drug being present. That adjustment is called physical dependence. Kosten and Baxter note that physical dependence on opioids can develop within weeks of starting them.

Withdrawal works like a mirror image of the drug's effects. SAMHSA states that withdrawal symptoms are generally the opposite of the drug's effects. SAMHSA's example: opioids shrink the pupils during use, and the pupils widen during withdrawal.

Kosten and Baxter report that patients may at first blame early withdrawal symptoms on a cold or the flu.

Kosten and Baxter describe physical dependence as a precursor, or early step, toward opioid use disorder (OUD), not the disorder itself. OUD has a wider set of signs of opioid addiction than physical dependence alone.

Withdrawal unfolds in stages, and each stage has its own symptoms and its own timing.

What happens at each stage of the opioid withdrawal timeline?

The opioid withdrawal timeline has four stages. Symptoms start within about 12 hours, peak at 36 to 72 hours and taper over the following 4 to 7 days. A protracted phase of low mood and poor sleep can then last weeks or months.

The figures below apply to short-acting opioids such as heroin and oxycodone. These figures come from a 2019 clinical review by Kosten and Baxter in the American Journal on Addictions and from a 2010 SAMHSA advisory.

SAMHSA puts the whole acute opioid withdrawal window at 4 to 10 days. SAMHSA notes that the length of withdrawal depends on the particular substance used.

MedlinePlus, the National Library of Medicine's health site, splits the symptoms into two waves. 8 early symptoms of opioid withdrawal:

• Agitation
• Anxiety
• Muscle aches
• Watery eyes
• Trouble sleeping
• Runny nose
• Sweating
• Yawning

6 later symptoms of opioid withdrawal:

• Stomach cramps
• Diarrhea
• Dilated pupils
• Goosebumps
• Nausea
• Vomiting

Kosten and Baxter note that withdrawal symptoms push patients back to opioid use early in an attempt to stop. The stage timings also shift with the type of opioid, because long-acting opioids leave the body more slowly.

How does the timeline differ between short-acting and long-acting opioids?

Short-acting opioids such as heroin and oxycodone produce withdrawal within about 12 hours, a peak at 36 to 72 hours and a taper over the next 4 to 7 days. Methadone withdrawal starts later, usually within 30 hours, feels milder, and may last 14 to 21 days.

The difference comes from how long each drug stays active in the body. A drug that clears quickly leaves the brain without support quickly, so withdrawal starts sooner and hits harder. A drug that clears slowly lets withdrawal build gradually over a longer stretch.

Buprenorphine

Kosten and Baxter describe buprenorphine as a long-acting opioid whose withdrawal can be less severe than short-acting withdrawal and of similar duration. Fentanyl complicates the timeline in a different way.

Is fentanyl withdrawal different?

For fentanyl, research documents a difference in treatment timing. A 2022 study found that buprenorphine taken within 48 hours of fentanyl raised the odds of sudden, severe withdrawal, called precipitated withdrawal. Methadone taken after fentanyl did not raise those odds.

No primary source sets out a separate hour-by-hour fentanyl withdrawal timeline.

Varshneya and colleagues explain that precipitated withdrawal happens when buprenorphine pushes fentanyl off the brain's opioid receptors. Wesson and Ling explain that buprenorphine can trigger withdrawal in highly dependent people who are not yet in withdrawal.

Varshneya and colleagues at Johns Hopkins surveyed 1,679 people seeking treatment across 49 US treatment centers. Taking buprenorphine within 24 hours of fentanyl raised the odds of severe withdrawal about fivefold. Of those who took buprenorphine less than 24 hours after fentanyl, 22.19% reported severe withdrawal.

The Varshneya findings rest on self-report, and the authors call for more research on how the body processes street fentanyl. The 24-hour window in this study is a different measure from how long fentanyl stays in your system on a drug test.

Precipitated withdrawal is severe, which raises the question of whether opioid withdrawal itself can kill.

Can opioid withdrawal kill you?

Opioid withdrawal itself is generally not fatal, but two dangers surround it. Severe vomiting and diarrhea cause dehydration that has proved fatal when poorly managed. Overdose after withdrawal is the second danger, because tolerance has dropped.

Kosten and Baxter state that opioid withdrawal is generally not fatal, but that deaths have occurred when rehydration was poorly managed, including in jails and prisons. MedlinePlus adds that vomiting and diarrhea drain the body's fluids and minerals, called electrolytes.

MedlinePlus names a second physical risk: breathing vomit into the lungs, called aspiration, which sometimes results in a lung infection.

The overdose danger arrives after the symptoms fade. MedlinePlus states that most opioid overdose deaths occur in people who have just detoxed. Withdrawal lowers tolerance, so a much smaller dose than before can now cause an overdose.

Strang and colleagues followed 137 people after inpatient opioid detox in London, in a study published in the BMJ in 2003. All three overdose deaths within four months came from the 37 people who completed both detox and the full inpatient program, and so had lost tolerance. None came from the group that left detox early and still tolerant.

Naloxone nasal spray (Narcan) reverses an opioid overdose, so keeping one on hand matters in this high-risk window. Tolerance loss overlaps with the next stage, the protracted phase.

What is the protracted phase of opioid withdrawal?

The protracted phase is the stretch after acute withdrawal ends, when anxiety, depression and poor sleep continue for weeks or months. SAMHSA also lists tiredness, irritability and feeling emotionally flat, and advises that these symptoms do not last forever.

SAMHSA's 2010 advisory on protracted withdrawal describes symptoms that follow the acute phase. The advisory calls the low, emotionally blunted mood dysphoria. SAMHSA also notes that people recovering from heroin show problems with focus and self-control that can persist for months.

SAMHSA notes that these symptoms lead some people to seek relief by returning to substance use. SAMHSA advises clinicians to reassure people that these symptoms will not last forever and can be managed.

SAMHSA also advises clinicians to consider methadone or buprenorphine for people whose protracted symptoms are strong and whose risk of returning to use is high. That advice points to what medically monitored withdrawal adds at every stage of the timeline.

What does medically monitored withdrawal change?

Medically monitored withdrawal changes three things. Clinicians score symptoms with a standard scale, treat symptoms with medication, and reduce the dehydration, dropout and overdose risks that Kosten and Baxter link to unmedicated withdrawal.

Clinicians score withdrawal with the Clinical Opiate Withdrawal Scale (COWS), published by Wesson and Ling in 2003. COWS is a clinician-administered scale that rates 11 common withdrawal signs and symptoms. The COWS total measures how severe withdrawal is and helps clinicians judge how physically dependent the person is.

Medication eases the symptoms. The FDA approved lofexidine in May 2018, the first non-opioid medication for opioid withdrawal symptoms in the United States. Its FDA label covers adults, to ease symptoms during an abrupt stop. Clonidine, a blood pressure medicine, is used off-label, meaning outside its FDA-approved uses, for the same purpose.

Kosten and Baxter warn that treating withdrawal without medication carries a very high risk, including dehydration, dropping out of care and overdose soon after dropping out. MedlinePlus lists other medicines that treat vomiting and diarrhea and help with sleep.

The FDA has approved 3 medications for opioid use disorder: buprenorphine, methadone and naltrexone. Naltrexone requires a gap first. The manufacturer recommends at least 7 to 10 opioid-free days before starting it, to avoid triggering sudden withdrawal.

2 emerging approaches to opioid withdrawal, neither yet established:

• Sublingual dexmedetomidine (BXCL501), taken under the tongue, reduced COWS scores at higher doses in a 2023 early-stage (phase 1b/2) trial. Only 33% of the 135 participants completed dosing, and the authors concluded that the findings support further development.
• Low-dose buprenorphine initiation, sometimes called micro-dosing, aims to avoid precipitated withdrawal after fentanyl. Varshneya and colleagues call for research comparing it with standard starts, so its benefit is not yet proven.

Frequently asked questions

Sources

1. Kosten, T. R. and Baxter, L. E. (2019). Review article: Effective management of opioid withdrawal symptoms: A gateway to opioid dependence treatment, American Journal on Addictions, 28(2), 55-62. Short-acting onset, peak and resolution; methadone and buprenorphine withdrawal; dehydration deaths; lofexidine approval; clonidine; naltrexone opioid-free period.
2. Substance Abuse and Mental Health Services Administration (2010). Protracted Withdrawal, Substance Abuse Treatment Advisory, 9(1), HHS Publication No. (SMA) 10-4554. Acute opioid and methadone withdrawal timeframes and protracted withdrawal symptoms.
3. National Library of Medicine (2026). Opiate and opioid withdrawal, MedlinePlus Medical Encyclopedia, reviewed 15 May 2026. Onset after heroin and methadone, early and late symptoms, dehydration, aspiration and overdose after detox.
4. Wesson, D. R. and Ling, W. (2003). The Clinical Opiate Withdrawal Scale (COWS), Journal of Psychoactive Drugs, 35(2), 253-259. The 11-item COWS and buprenorphine-precipitated withdrawal.
5. Strang, J. et al. (2003). Loss of tolerance and overdose mortality after inpatient opiate detoxification: follow up study, BMJ, 326(7396), 959-960. Overdose deaths after completed detox.
6. Varshneya, N. B. et al. (2022). Evidence of Buprenorphine-precipitated Withdrawal in Persons Who Use Fentanyl, Journal of Addiction Medicine, 16(4), e265-e268. Precipitated withdrawal after recent fentanyl use.
7. US Food and Drug Administration (2018 and 2024). LUCEMYRA (lofexidine) prescribing information and Information about Medications for Opioid Use Disorder (MOUD). Lofexidine indication and the three FDA-approved medications for opioid use disorder.
8. Jones, J. D. et al. (2023). Sublingual dexmedetomidine (BXCL501) reduces opioid withdrawal symptoms: findings from a multi-site, phase 1b/2, randomized, double-blind, placebo-controlled trial, American Journal of Drug and Alcohol Abuse, 49(1), 109-122. Emerging treatment status.