Opioid Withdrawal: Symptoms and Day-by-Day Timeline

Opioid withdrawal from short-acting opioids (heroin, oxycodone immediate release, fentanyl) begins 6-12 hours after the last dose, peaks between 36 and 72 hours, and the acute symptoms usually settle within 5-7 days. Long-acting opioids — methadone in particular — produce a slower, longer withdrawal that takes 10-20 days to clear (WHO Clinical Guidelines, 2009). What follows is an honest day-by-day account of what to expect, why supervised withdrawal protects you during the peak, and which medications actually change the experience.

Why Does the Opioid Withdrawal Timeline Differ So Much Between Drugs?

The timeline depends almost entirely on the half-life of the opioid you were taking. Short-acting drugs like heroin clear the body fast, so withdrawal starts within hours and burns hot. Long-acting drugs like methadone linger for days, so withdrawal starts later, lasts longer, and feels less acute but more drawn out (WHO Clinical Guidelines, 2009).

The half-life is the time it takes your body to clear half the drug from your system. Heroin and fentanyl have half-lives measured in minutes to hours. Methadone has a half-life that can stretch to 24-36 hours, which is exactly why it’s used for maintenance and tapering — it provides steady coverage without the spikes and crashes of shorter-acting drugs.

A useful shorthand: the faster a drug hits and wears off, the faster and sharper the withdrawal. The slower it leaves the body, the more dragged out the discomfort.

What Are the Actual Symptoms of Opioid Withdrawal?

Opioid withdrawal produces a cluster of physical and psychological symptoms that hit together: muscle and bone pain, abdominal cramps, vomiting, diarrhoea, profuse sweating, runny nose and tearing eyes, dilated pupils, gooseflesh, yawning, restless legs, insomnia, anxiety, irritability, and intense drug craving. The clinical scoring tool used in hospitals — COWS — tracks eleven of these signs (Wesson & Ling, J Psychoactive Drugs, 2003).

People who have been through it describe it as “the worst flu you can imagine, with anxiety running underneath it all”. The flu comparison is accurate for the physical symptoms — gastrointestinal misery, body aches, sweats and chills. What the flu doesn’t capture is the psychological intensity: a relentless craving, vivid drug-seeking dreams, the certainty that one dose would end the suffering immediately. That certainty is what drives most relapses during the peak.

Symptoms cluster roughly into three buckets:

• Gastrointestinal: Nausea, vomiting, abdominal cramps, diarrhoea. Often the most physically draining symptoms because dehydration compounds everything else.
• Autonomic and musculoskeletal: Sweating, runny nose, tearing eyes, dilated pupils, yawning, gooseflesh, muscle aches, bone pain, restless legs. These are the body’s noradrenaline system rebounding after months or years of opioid suppression.
• Psychological and sleep: Anxiety, irritability, restlessness, insomnia, vivid dreams about using, intense craving. These often outlast the physical symptoms by weeks.

What Does the Day-by-Day Timeline Actually Look Like?

For short-acting opioids, withdrawal follows a recognisable arc: discomfort begins on day 1, peaks between day 2 and day 3, then eases steadily from day 4 onwards. By day 7 most physical symptoms have resolved, though sleep, mood, and cravings can persist much longer. Long-acting opioids stretch this same arc over two to three weeks (WHO Clinical Guidelines, 2009).

Short-acting opioids (heroin, oxycodone IR, illicit fentanyl):

Long-acting opioids (methadone): The same arc plays out over 2-3 weeks. Withdrawal symptoms may not begin until 24-48 hours after the last dose. The peak is less acute than with heroin but more sustained — days 3 through 8 are typically the hardest, with the worst sleep disruption, muscle pain, and anxiety. Acute symptoms can take a full 20 days to resolve, which is why a structured taper is almost always preferable to abrupt cessation.

Is Opioid Withdrawal Dangerous or Life-Threatening?

Opioid withdrawal alone is rarely life-threatening in physically healthy adults — this is the key clinical difference from alcohol or benzodiazepine withdrawal, which can cause seizures and death. The serious danger with opioids is the overdose risk if you relapse after detox, because tolerance drops sharply within days and a previous “normal” dose becomes a fatal one (NIDA, 2024).

That said, “not usually life-threatening” is not the same as “safe to do alone”. Several scenarios make supervised withdrawal genuinely important, not optional:

• Pregnancy. Sudden opioid withdrawal in pregnancy can cause foetal distress, preterm labour, or miscarriage. Tapered methadone or buprenorphine under specialist care is the medical standard.
• Severe vomiting and diarrhoea. Dehydration and electrolyte imbalance can become dangerous, particularly for people with heart, kidney, or other chronic conditions.
• Polysubstance use. If you’re also dependent on alcohol or benzodiazepines, those withdrawals are potentially fatal and change the whole risk picture.
• Underlying medical conditions. Heart disease, severe anxiety disorders, or unmanaged psychiatric conditions can be destabilised by the autonomic surge of withdrawal.
• History of overdose. A previous near-fatal overdose raises the stakes if relapse happens during the peak.

For these clients we may detox first at our partner hospital — which has intensive and intermediary intensive care units — before transferring to One Step for the rehab programme. Most opioid clients without those complications detox on-site here with medication support.

The hardest part of opioid withdrawal isn’t the physical pain on day 3 — it’s the certainty in your own head that one dose would make it stop. That’s why supervised withdrawal isn’t really about the symptoms; it’s about removing the option to relapse for the 72 hours when your brain is screaming for the drug.

Dr. Worapakthorn KongpesalaphunConsultant Psychiatrist, One Step Rehab

Which Medications Are Used to Manage Opioid Withdrawal?

Three medication approaches dominate modern opioid withdrawal management: buprenorphine induction (the current first-line option), a methadone taper (used most often when transitioning off long-term methadone maintenance), and alpha-2 agonists like lofexidine or clonidine (which suppress physical symptoms without being opioids themselves). These transform the withdrawal experience from unbearable to manageable for most people (SAMHSA TIP 63, 2021).

Buprenorphine induction. Buprenorphine is a partial opioid agonist that binds tightly to the same receptors as heroin or oxycodone but produces a much milder effect. Started at the right moment — usually when withdrawal is already clearly underway (roughly 12-24 hours after the last short-acting opioid dose, with COWS score above 12) — it relieves symptoms within an hour and stabilises mood, sleep, and cravings within days. Starting too early can trigger precipitated withdrawal, which is sudden and severe. Timing matters.

Methadone taper. Methadone is a long-acting full opioid agonist. For people coming off another short-acting opioid, doctors may stabilise on a low dose of methadone and then taper down over 6-30 days. For people already on long-term methadone maintenance, a slow taper of 10-25% reductions every 2-4 weeks is the standard approach to minimise rebound symptoms (WHO Clinical Guidelines, 2009).

Lofexidine and clonidine. These are alpha-2 adrenergic agonists. They don’t activate opioid receptors at all — they calm the noradrenaline rebound that drives sweating, cramps, anxiety, runny nose, and gooseflesh. Cochrane reviews show they’re roughly as effective as a methadone taper for managing withdrawal symptoms, with lofexidine causing less blood pressure drop than clonidine and being better suited to outpatient or residential settings (Gowing et al., Cochrane Database Syst Rev, 2016).

What Is Post-Acute Withdrawal Syndrome and How Long Does It Last?

Post-acute withdrawal syndrome (PAWS) is a constellation of lower-grade symptoms — depressed mood, anxiety, poor sleep, fatigue, irritability, waves of craving — that can persist for weeks to months after the acute physical withdrawal has ended. For opioids, PAWS often peaks around 2-12 weeks post-detox and can linger in milder form for 6-9 months in some people.

This is the phase that catches most people off guard. The acute withdrawal feels like a finite event with a clear end date. PAWS feels open-ended, which is part of what makes it dangerous — it’s easy to interpret persistent low mood and sleep problems as “this isn’t working, I should use again”. It is working; this is just the slower phase.

What helps during PAWS:

• Structure. A predictable daily schedule reduces the mood swings that come with idle time and rumination.
• Sleep hygiene. Sleep is one of the last things to return to normal. Consistent wake times, no caffeine after midday, no screens in bed.
• Exercise. Moderate exercise reliably improves mood, sleep, and energy in early recovery — usually noticeable within 2-3 weeks.
• Naltrexone or maintenance buprenorphine. For clients with strong cravings or repeated relapse, longer-term medication can take craving largely off the table.
• Knowing it’s a phase. The single most useful thing is to label what’s happening — “this is PAWS, not me failing” — and to keep going.

How Does One Step Handle Opioid Withdrawal?

At One Step we handle most opioid detoxes on-site as part of our opioid rehab programme. The medication approach is selected by our visiting psychiatrist based on which opioid you were using, how much, for how long, and whether you have other dependencies or medical conditions. Buprenorphine induction is the most common protocol for short-acting opioid dependence; lofexidine plus symptomatic medication is the most common non-opioid alternative. The residential treatment programme follows immediately, so you don’t go home into the relapse window.

For clients with heavy long-term opioid use, complicating medical conditions, or polysubstance dependence involving alcohol or benzodiazepines, we may detox you first at our partner hospital — which has intensive and intermediary intensive care units — before you transfer to One Step for the rehab programme. The intake assessment determines which path is appropriate; we don’t try to handle severe medical detox on-site when hospital monitoring is the safer call.

Practical details of the residential stay:

• Programme length: 28, 60, or 90 days. Opioid clients usually benefit from a longer stay because the PAWS tail and relapse risk extend well beyond the acute phase.
• Cost: ฿280,000 per month (~$8,500 USD). Medication prescribed during your stay — including buprenorphine, lofexidine, methadone, naltrexone, and symptomatic drugs — is billed separately. The pricing page lists exactly what the fee covers and what’s billed on top.
• Schedule: Structured daily programme of group therapy, individual counselling, and fitness, designed around the withdrawal arc — light demands in the acute phase, full programme by week 2.
• Detox referral: Severe cases are referred to our partner hospital for detox stabilisation first, then transferred to One Step.
• Aftercare: Continued support through the PAWS window is built into the aftercare programme — weekly online groups, alumni community, relapse-prevention check-ins.

One Step is a residential rehab, not an ICU. For the highest-acuity opioid cases — heavy long-term use, polysubstance dependence with alcohol or benzodiazepines, pregnancy, serious heart or lung disease — the partner hospital handles the medical detox first, then you transfer to us.

Why Does Supervised Withdrawal Reduce Relapse Risk?

The 72-hour peak of opioid withdrawal is the highest-risk window for relapse. Cravings are maximal, distress is maximal, and the brain is loudly insisting that one dose would end the suffering. Removing access to opioids during that window — by being somewhere you cannot get them — is the single biggest factor that helps people get through. Medication support takes the edge off the symptoms so willpower isn’t the only thing standing between you and using.

Several other reasons supervised withdrawal matters:

• Overdose protection. If you relapse after a few days of withdrawal at home, your tolerance has dropped sharply. A dose that was previously normal can now stop your breathing. Many opioid overdose deaths happen in the first month after a withdrawal attempt.
• Dehydration management. Vomiting and diarrhoea at peak can become medically serious without fluid replacement and basic monitoring.
• Sleep and anxiety support. Insomnia and anxiety are often what tip someone into “I’ll just use to sleep”. On-site staff and medication can break that loop.
• Building a bridge to treatment. Detox alone has high relapse rates; detox into a residential programme is dramatically more effective for sustained recovery (SAMHSA TIP 63, 2021).

If you’re weighing detoxing alone versus a residential setting, the difference isn’t comfort — it’s outcome. Our inpatient vs outpatient comparison covers this in more depth. The relapse risk during withdrawal guide covers the specific tactics that work in the first week.

For comparison with other detox timelines: meth withdrawal has no clean peak day and stretches out over a longer crash and PAWS arc; alcohol withdrawal has the opposite risk profile — milder physical symptoms for many people, but a real risk of seizures and delirium tremens that opioid withdrawal lacks. Knowing which class of drug you’re dealing with is the first step in planning a withdrawal.