Key takeaway
You are trying to use a withdrawal chart as a plan for quitting at home. The clock depends on the drug. Early withdrawal from short-acting opioids can start in 8 to 24 hours, and long-acting opioids can take longer. A return to use after tolerance drops can stop breathing. Tell a clinician tonight. Do not quit alone.
Last updated: Mon Oct 05 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
You have a chart of hours, and you are about to use it as a plan for quitting on the couch. The clock depends on the drug. Tell a clinician what you last used, whether methadone or buprenorphine is already prescribed, and whether alcohol or a benzodiazepine is also in the picture. Do not quit those alone.
If someone is not breathing, will not wake, or is turning blue, call 911. Give naloxone if you have it, and stay. For a mental health crisis, call or text 988.
Two clocks
Early withdrawal from short-acting opioids is listed at 8 to 24 hours after the last use, and early withdrawal from long-acting opioids at up to 36 hours. Fully developed withdrawal comes later: 1 to 3 days for short-acting opioids, and 72 to 96 hours for long-acting ones. The exhibit's total span is about 7 to 10 days for short-acting opioids and 14 days or more for long-acting ones. Those ranges are what clinicians watch. They are not a home calendar, and they are not a score for the kitchen table.
Early signs can include tearing, a runny nose, sweating, yawning, restlessness, and insomnia, then dilated pupils, goosebumps, muscle and joint pain, and abdominal pain. Later signs can include a fast heartbeat, fever, nausea, extreme restlessness, then diarrhea or vomiting, dehydration, and a curled-up position. A person can feel awful early and still be headed into the later window. The exhibit describes signs. It does not promise that every person hits every grade.
Methadone stays in the body longer than heroin or fentanyl and activates the same receptors more slowly. A methadone stop belongs on the long-acting side, not on a one-day heroin story. Heroin-specific timing is in heroin treatment. If you do not know what was in the last dose, say that. Illegally made fentanyl is commonly mixed into heroin and cannot be seen, tasted, or smelled. What that does to overdose risk is in fentanyl treatment.
Alcohol withdrawal is a different emergency. It can seize and it can kill. Uncomplicated opioid withdrawal is not life-threatening, unlike withdrawal from alcohol or sedatives. That contrast is not a reason to minimize the week, and it is not a reason to stop alcohol or a benzodiazepine on the opioid clock. Stopping a benzodiazepine abruptly, or cutting it too fast, can cause seizures. Say both drugs at the first call. The alcohol hours are in the alcohol detox timeline.
Uncomfortable, and still a reason for medicine
The same detoxification guide says clinicians should not try to manage significant opioid withdrawal without effective medication. Heavy vomiting or diarrhea can dehydrate someone enough to be dangerous. Fluids matter. They are not a substitute for an assessment. Pregnancy is a reason to talk with a clinician before stopping, not a reason to stop in order to protect the pregnancy.
Lofexidine is approved for acute symptoms after a sudden opioid stop: feeling sick, stomach cramps, muscle spasms, a pounding heart, aches, or sleep problems. It is not long-term treatment, and it does not replace methadone, buprenorphine, or naltrexone. Those three treat the disorder. Stopping methadone or buprenorphine abruptly can bring withdrawal. A slow reduction, if one happens at all, belongs to a clinician. Many people stay on the medicine. How they differ is in medication for opioid use disorder and in methadone compared with buprenorphine.
Naltrexone is usually started only after 7 to 10 days without other opioids, because an earlier start can cause withdrawal. Faster starts exist only under clinical care. Do not take a leftover tablet to see what happens.
The risk after the sweats stop
People who return to opioids after abstinence have lost tolerance and may not know what amount they can tolerate. A dose that used to be ordinary can stop breathing. Detoxification that ends when the acute signs fade leaves you at that moment. Detoxification alone is not sufficient treatment. The three parts are evaluation, stabilization, and a way into ongoing care. Why the first part is not the whole course is in detox at home versus medical care. Slowed breathing and naloxone are in opioid overdose signs.
Kratom is not this clock. There is no approved therapy for kratom withdrawal, which kratom withdrawal explains. A scale such as COWS is a clinician's tool, in the opioid withdrawal scale.
Search FindTreatment.gov for opioid treatment. Call or text (800) 653-9376 if you need a program that continues medication rather than stopping it at the door.
Additional Resources
Sources cited on this page:
- SAMHSA TIP 63: Exhibit 2.10, physical signs of opioid withdrawal and time to onset (NCBI Bookshelf)
- SAMHSA TIP 45 quick guide, excerpted in NCBI Bookshelf (TIP 49, Appendix C)
- NIDA: Medications for Opioid Use Disorder
- NIDA: Misconceptions about maintenance treatment (tolerance and return to use)
- SAMHSA: Overdose Prevention and Response Toolkit
- CDC: Fentanyl Facts
- FDA: Boxed warning on benzodiazepines
- SAMHSA FindTreatment.gov
- 988 Suicide & Crisis Lifeline
Common Questions
When does opioid withdrawal start?
TIP 63 puts early withdrawal from short-acting opioids at 8 to 24 hours after the last use, and early withdrawal from long-acting opioids at up to 36 hours. Fully developed withdrawal is listed at 1 to 3 days for short-acting opioids and at 72 to 96 hours for long-acting ones. Those are clinical ranges. They are not permission to wait out symptoms alone.
How long does it last?
The same exhibit lists about 7 to 10 days for short-acting opioids and 14 days or more for long-acting opioids. Methadone stays in the body longer than heroin or fentanyl, so a methadone stop is the long clock. Stopping prescribed methadone or buprenorphine suddenly can cause withdrawal. A prescriber should manage that change.
Is opioid withdrawal usually fatal?
TIP 45 says uncomplicated opioid withdrawal is not life-threatening, unlike alcohol or sedative withdrawal. It also says significant opioid withdrawal should not be managed without effective medication. Heavy vomiting or diarrhea can dehydrate someone enough to be dangerous. Confusion, collapse, a seizure, or trouble breathing needs emergency care.
Which medicines ease symptoms, and which treat the disorder?
Lofexidine is approved for acute symptoms such as feeling sick, stomach cramps, muscle spasms, a pounding heart, aches, and sleep problems. It is not long-term treatment. Methadone, buprenorphine, and naltrexone treat opioid use disorder. Naltrexone is usually started only after 7 to 10 days without other opioids, because starting sooner can cause withdrawal. A clinician manages that gap.
Why is the danger often after the sweats stop?
People lose tolerance during abstinence, often without realizing it, so an amount they used to take can stop breathing. Illegally made fentanyl is commonly mixed into heroin and cannot be seen, tasted, or smelled. Detoxification alone is not treatment. If breathing slows, that is an emergency, whether or not the chart said withdrawal should be over.