Opioid Withdrawal Symptoms — What Your Body Goes Through
Opioid withdrawal is often compared to the worst flu you've ever had. Except it lasts longer, hurts more, and comes with cravings that make you want to do anything to make it stop. For most people, medical supervision isn't optional — it's the difference between getting through this and not. Here's every symptom, what's actually happening in your body, and when it peaks.
Before we get into the specifics: if you're currently in crisis, skip to our crisis support page.
What Is Opioid Withdrawal?
Your brain adapts to opioids. That's not a character flaw — it's biology. Opioids bind to receptors that regulate pain, mood, digestion, and your autonomic nervous system. Over time, your brain downregulates its own natural opioid production and recalibrates around the drug. When the drug stops, the system overcorrects hard in the other direction.
That overcorrection is withdrawal. Every system that opioids suppressed comes roaring back at full volume. Pain sensitivity skyrockets. Your gut goes haywire. Your nervous system fires on overdrive. And your brain, now short on dopamine, screams at you to fix it.
The severity depends on which opioid you were taking, how long you took it, the dose, and your individual physiology. Short-acting opioids — like heroin or immediate-release oxycodone — hit faster and harder. Long-acting opioids like methadone produce a slower, more drawn-out withdrawal.
Early Opioid Withdrawal Symptoms (6–24 Hours)
For short-acting opioids, symptoms usually start within 6–12 hours of the last dose. For long-acting opioids, it can be 24–36 hours before things ramp up.
This first phase feels bad, but it's not the worst yet.
| Symptom | What's Happening |
|---|---|
| Anxiety and restlessness | CNS hyperactivity as opioid suppression lifts. Your nervous system has been running in low gear — now it's suddenly in high. |
| Muscle aches | Pain pathways are reactivating without opioid blockade. Everything that was numbed is coming back online at once. |
| Increased tearing / runny nose | Autonomic nervous system rebound. Your secretory functions were suppressed. Now they're not. |
| Sweating | Thermoregulation disruption. Your hypothalamus is misfiring as it tries to recalibrate. |
| Yawning | The mechanism isn't fully understood, but it's one of the most consistent early signs. |
| Insomnia | Sleep architecture is disrupted during withdrawal. REM sleep in particular takes a hit. |
These symptoms are uncomfortable but manageable for most people. Don't mistake "manageable" for "no big deal" — sleep deprivation alone makes everything harder.
Peak Opioid Withdrawal Symptoms (24–72 Hours)
This is where most people tap out. Peak withdrawal hits hard, and it hits everything at once.
| Symptom | What's Happening |
|---|---|
| Nausea and vomiting | GI rebound. Opioids suppress nausea — remove them, and the opposite happens. |
| Diarrhoea | GI motility returning after opioid-induced slowdown. Your gut speeds up fast. |
| Abdominal cramps | GI spasm as motility normalises. It can be severe. |
| Dilated pupils | Autonomic rebound. Opioids cause pupil constriction. Without them, pupils dilate. |
| Goosebumps (piloerection) | This is where "cold turkey" comes from — the skin resembles a plucked turkey. Autonomic misfiring causes the hair follicles to contract involuntarily. |
| Rapid heartbeat | Cardiovascular rebound. Heart rate and blood pressure both spike. |
| High blood pressure | Related to the same autonomic rebound driving the heart rate increase. |
| Intense cravings | A dopamine deficit combined with conditioned responses. Your brain knows exactly what would fix this — and it won't stop reminding you. |
The combination of vomiting, diarrhoea, and sweating can cause serious dehydration. Fast. If you can't keep fluids down, that's a medical emergency — not a sign to push through.
Why Medical Supervision Matters
Let's be direct: opioid withdrawal without medical supervision is risky.
It's not always directly fatal in otherwise healthy adults — unlike alcohol or benzodiazepine withdrawal, opioid withdrawal rarely causes seizures or death from the withdrawal process itself. But the complications are real and serious.
Dehydration. Severe vomiting and diarrhoea can deplete fluids and electrolytes faster than most people expect. Electrolyte imbalances affect heart rhythm. That's not theoretical — it happens.
Aspiration risk. If you're vomiting while incapacitated and no one's around, there's a risk of aspirating vomit. That can be fatal.
Cardiovascular strain. The blood pressure and heart rate spikes during peak withdrawal are significant. If you have underlying cardiovascular conditions, this matters a lot.
Mental state. Severe anxiety, paranoia, and sleep deprivation during withdrawal impair judgment. Decisions made in that state — including the decision to use again — can be fatal (more on that below).
Medically assisted treatment (MAT) significantly reduces the severity of withdrawal symptoms and improves the odds of getting through it. Medications used in MAT work by targeting the same receptors, easing the transition rather than demanding your body handle everything cold. Don't white-knuckle this if you don't have to. Talk to a doctor before you stop.
For a full breakdown of what to expect day by day, see the opioid withdrawal timeline.
The Psychological Symptoms
Physical symptoms get most of the attention. The psychological symptoms stick around longer and are harder to describe.
Depression. Opioids flood the brain's reward system. After chronic use, the brain's ability to produce natural dopamine and feel ordinary pleasure is impaired. In withdrawal, that feels like a grey, flat emptiness. It's not permanent, but it doesn't lift overnight.
Anxiety. Heightened and often out of proportion to what's happening. The nervous system is still recalibrating. Everything feels more threatening than it is.
Irritability. Small things feel intolerable. Patience runs at zero. This is neurochemistry, not personality.
Anhedonia. The inability to feel pleasure. Things that used to feel good don't. Food, music, conversation — all flat. This is one of the hardest parts because it makes it hard to see the point of staying off opioids.
Difficulty concentrating. Brain fog is real. Cognitive function during and after withdrawal is genuinely impaired. Give yourself time.
Paranoia. Not universal, but common enough to flag. The anxiety can tip into a more paranoid, hypervigilant state.
These symptoms are part of what's called Post-Acute Withdrawal Syndrome (PAWS). PAWS can persist for weeks to months after physical withdrawal ends. It's why people who feel physically fine at two weeks sometimes relapse at month two. The psychological withdrawal has a longer tail than most people are prepared for.
The Danger After Withdrawal — Tolerance Drop
This is the part that doesn't get said enough.
After withdrawal, your tolerance drops significantly. Your body no longer has the adaptation it built up over months or years of use. A dose that felt normal before quitting can now cause a fatal overdose.
Most opioid overdose deaths don't happen during active addiction. They happen during relapse — after a period of abstinence, when tolerance is gone and people return to their previous dose without realising how dangerous that now is.
This is not a reason to avoid quitting. It's a reason to take relapse prevention seriously and to track your recovery. If you're struggling right now, go to our crisis support page.
Frequently Asked Questions
How bad is opioid withdrawal?
Bad. There's no point dressing it up. Most people describe it as the worst physical experience of their lives — a combination of severe flu-like symptoms, intense muscle aches, GI distress, and psychological symptoms all at once. The severity varies depending on the opioid, duration of use, and individual factors. For some people, it's severe enough to require hospitalisation.
Can opioid withdrawal kill you?
It's less directly lethal than alcohol or benzodiazepine withdrawal, but it's not safe to dismiss. Severe dehydration from vomiting and diarrhoea can cause dangerous electrolyte imbalances. Aspiration of vomit is a real risk. And the period immediately after withdrawal — when tolerance has dropped — is when overdose risk is highest. Medical supervision during withdrawal significantly reduces these risks.
What helps with opioid withdrawal symptoms?
Medically assisted treatment is the most effective option. Medications prescribed and monitored by a doctor can dramatically reduce symptom severity. Beyond that: hydration is critical, rest matters, and having medical oversight means complications get caught early. What doesn't help — despite how tempting it feels — is using again to stop the symptoms. That resets the clock and puts you at risk.
The Bottom Line
Opioid withdrawal is genuinely hard. Your body goes through a full physiological reversal, and your brain spends most of it trying to convince you there's an easy fix. There isn't. But understanding what's happening and why makes it less chaotic — and medical supervision makes it survivable.
If you're planning to quit opioids, don't do it alone. Talk to a doctor first.
Written by 180 - Benjy. This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making changes to any medication or treatment plan. No specific medication dosages are provided in this article — your doctor will guide that based on your individual situation.
If you're in crisis, please visit our crisis support page.