Opioid & Opiate Detox: How Medical Detox Works

Clinically reviewed by Robin Lefever, Therapist and Registered Manager. Last reviewed: 22 June 2026.

If you or someone you love is dependent on opioids or opiates, the questions are usually the same: how does a detox actually work, is it safe, and can it be done at home or does it need to be in a clinic? The short answer is that a planned, medically supervised detox is the safest way to come off opioids. Withdrawal from opioids is rarely life-threatening in itself, but doing it without support is distressing, hard to sustain, and carries a serious hidden danger after detox: a return to a previous dose can cause a fatal overdose because tolerance falls quickly.

This page explains how medical detox works, the realistic options including a supervised home detox, and how Promis can help.

This is general information, not personal medical advice. If you want an opinion on your own situation, book a confidential assessment and we will talk it through with you.

What is an opioid (opiate) detox?

"Opiate" usually means a drug derived from the opium poppy, such as heroin, morphine or codeine. "Opioid" is the broader term that also covers synthetic and prescription medicines such as oxycodone, tramadol and fentanyl. In everyday use, and in most searches, the words are used to mean the same thing, and a detox works the same way for both.

A detox, or detoxification, is the process of safely clearing the drug from the body and managing the withdrawal symptoms that follow when someone who is physically dependent stops taking it. Physical dependence means the body has adapted to the drug, so stopping triggers a set of symptoms. These symptoms are extremely uncomfortable but, on their own, opioid withdrawal is rarely dangerous to life in the way that unmanaged alcohol or benzodiazepine withdrawal can be.

Withdrawal symptoms often build in two waves. The descriptions below are general and individual experience varies.

Early symptoms can include:

• a runny nose and watering eyes
• yawning and sweating
• restlessness and agitation
• aches in the muscles and joints
• trouble sleeping

More intense symptoms can include:

• stomach cramps, nausea and vomiting
• diarrhoea
• a faster heartbeat and raised blood pressure
• goosebumps and shivering
• strong cravings and low mood

If you want to read an independent overview, the NHS has a guide to getting help with heroin and opioids.

The point worth holding on to from the start is that detox is the beginning of treatment, not the whole of it. Clearing the drug removes the physical dependence. Staying well afterwards is a separate piece of work. NICE guidance on opioid detoxification (NICE CG52) is clear that detox should be offered as part of a wider treatment plan, not as a standalone event.

What does the opioid withdrawal timeline look like?

People often want a rough sense of how withdrawal unfolds over time. The table below is a general, descriptive guide to the typical stages. Exact timing varies by the opioid involved and by the person, and is assessed individually as part of the plan.

• Stage: Onset · When: Around 6 to 30 hours after the last use, depending on the opioid · What can happen: First symptoms begin, often a runny nose, yawning, sweating and restlessness
• Stage: Peak · When: Around 24 to 72 hours · What can happen: Symptoms are usually at their most intense, including cramps, nausea and strong cravings
• Stage: Acute symptoms easing · When: Around 5 to 10 days · What can happen: The sharpest physical symptoms gradually settle
• Stage: Protracted symptoms · When: Weeks beyond the acute phase · What can happen: Low mood, disturbed sleep and cravings can persist for a time

Shorter-acting opioids tend to bring withdrawal on sooner and over a more compressed window, while longer-acting ones tend to start later and last longer. Your assessment looks at which opioid is involved and at your own circumstances, so the plan reflects your situation rather than an average.

How does medically supervised opioid detox work?

A good medical detox is planned, not improvised. There are three broad stages.

1. Assessment. Before anything else, there is a thorough assessment of what you are using, how much, for how long, your physical health, your mental health, and your home circumstances. This matters because opioid dependence often sits alongside anxiety, depression, trauma or other drug and alcohol use, and the plan has to account for all of it. Promis is a mental health and addiction clinic with weekly psychiatric input, so the assessment looks at the whole picture, not just the substance. You can read more about the assessment programme and what it involves.

2. Medication-assisted withdrawal. Most planned opioid detoxes are medication-assisted, which means medicine is used to take the edge off withdrawal and keep the process safe and bearable, prescribed and reviewed by a doctor.

Medicines that may be used (chosen and dosed individually at assessment, not listed here):

• methadone, a substitute opioid used to ease withdrawal and then gradually reduce
• buprenorphine, a partial substitute opioid used in a similar way
• lofexidine, which eases the physical symptoms of withdrawal

We do not publish dosing here because doses are decided individually by the prescribing clinician based on the assessment; the right medicine and schedule for one person is wrong for another. NICE CG52 sets out the framework for this in UK services.

3. Monitoring and support. Throughout the detox, symptoms and observations are monitored, the medication plan is adjusted as needed, and there is practical and emotional support alongside it. The aim is a controlled, gradual reduction rather than an abrupt stop, so the body has time to adjust.

You can see how this is structured in our detox service, which is always assessment-led and connected to ongoing treatment rather than offered in isolation.

Can you detox from opiates at home?

Yes, a home detox from opiates is possible for some people, but only with proper medical supervision and only after a face-to-face style assessment has confirmed it is suitable. A medically supervised home detox is not the same as stopping on your own at home, which we would not advise; the difference is the prescribing, the monitoring and the support wrapped around it.

A home detox can suit someone who is physically stable, has a safe and supportive home environment, and is motivated to keep to the plan. It is less suitable where there is heavy or long-standing dependence, significant physical or mental health problems, high overdose risk, previous complicated withdrawals, or a chaotic or unsupportive home setting. In those situations an inpatient detox is usually safer. The decision is always made on the assessment, never assumed. Our detox service covers both routes so the plan can be matched to the person.

Choosing between inpatient detox and supervised home detox

There is no single right answer here. It depends on the severity of dependence, physical and mental health, risk, and home circumstances. The table below is a guide to who each route tends to suit.

• Setting · Inpatient / residential detox: One of our small inpatient clinics (Hay Farm in Kent, or Kendrick Mews in London) · Medically supervised home detox: Your own home, with a prescribed plan and monitoring
• Tends to suit · Inpatient / residential detox: Heavier or long-standing dependence, physical or mental health complications, higher risk, previous difficult withdrawals, an unsupportive home · Medically supervised home detox: Milder or shorter dependence, good physical health, a safe and supportive home, strong motivation
• Support level · Inpatient / residential detox: Round-the-clock clinical environment and immediate support · Medically supervised home detox: Scheduled reviews and remote support, relying on the home setting
• Decided by · Inpatient / residential detox: Assessment · Medically supervised home detox: Assessment

Both are voluntary. Promis provides planned, voluntary treatment, not acute or emergency care. If you are unsure which route fits, that is exactly what the assessment is for.

Safety: the overdose risk after detox, and why detox is not the finish line

This is the most important section on the page, so please do not skip it.

During a detox, tolerance to opioids falls quickly. Tolerance is the body's adaptation to the drug; as it drops, the amount the body can handle drops with it. This creates a serious and well-documented danger: if someone relapses after a detox and takes the dose they were used to before, that previous dose can now be enough to cause a fatal overdose. The period straight after detox is one of the highest-risk times for opioid overdose, which is why relapse prevention and aftercare are not optional extras. This risk is recognised by the NHS and the Royal College of Psychiatrists.

Two practical points follow from this:

• Detox alone is not treatment. Clearing the drug from the body without addressing why the dependence developed, and without a plan to stay well, leaves the underlying problem untouched and the overdose risk high. Detox should always be followed by relapse-prevention work and aftercare.
• Know the urgent signposting. If someone has overdosed or you cannot wake them, their breathing is slow or has stopped, or their lips or fingertips look blue, call 999 immediately. For urgent advice that is not an emergency, call NHS 111. These NHS routes are there day and night.

Withdrawal symptoms are deeply unpleasant but rarely fatal on their own. The greater danger sits on the other side of detox, in tolerance loss and relapse, which is precisely why a planned programme with aftercare is safer than going it alone.

So what does that aftercare actually look like? In practice it means regular therapy that addresses why the dependence developed and builds relapse-prevention skills, support for any co-occurring mental health difficulties such as anxiety, depression or trauma, and a structured aftercare plan that keeps you connected to help in the weeks and months after detox. This is the part that turns a completed detox into lasting recovery, and it is the reason detox on its own is not treatment.

How Promis can help

Promis provides medically supervised opioid and opiate detox as part of a wider treatment plan, never as a standalone event. In practice that means:

• Assessment first. Everything starts with a confidential assessment that looks at the substance, your physical and mental health, and your circumstances, so the plan fits you.
• A detox matched to you. We offer both inpatient detox at our two small clinics and a medically supervised home detox for suitable people, with medication prescribed and reviewed by a doctor and weekly psychiatric input across the service. See the detox service for how it is structured.
• Treatment that continues after detox. Because detox is the start and not the end, we connect it to ongoing therapy and relapse prevention through our wider drug addiction treatment, so the work of staying well actually gets done.

On fees, we keep it honest: what a detox costs depends on the route and the length of the plan, so it follows from the assessment rather than a fixed figure online. The clearest first step is a confidential assessment, and you are welcome to contact us to talk through the practicalities.

If you would like to talk to someone in confidence, contact us and we will help you work out the right next step.

Frequently asked questions

How long does an opioid detox take?

It varies with the medicine used and the individual. A buprenorphine or methadone-based reduction is gradual and can run over a number of weeks, while a lofexidine-supported withdrawal of physical symptoms is usually shorter. Your assessment determines the length, and a slower, well-tolerated detox is generally preferred to a rushed one.

What medication is used in an opioid detox?

In UK practice the medicines used include methadone, buprenorphine and lofexidine, prescribed and reviewed by a doctor in line with NICE CG52. We do not publish doses because they are set individually at assessment. The right choice depends on the person, not a fixed formula.

Is opiate detox dangerous?

Opioid withdrawal is rarely life-threatening on its own, unlike unmanaged alcohol or benzodiazepine withdrawal. The real danger is afterwards: tolerance falls during detox, so relapsing and taking a previous dose can cause a fatal overdose. That is why supervision and aftercare matter so much.

Can I detox from opiates at home?

For some people, yes, with medical supervision and only after an assessment confirms it is suitable. It is not advisable to detox unsupervised. Where dependence is heavy or there are health or safety concerns, an inpatient detox is usually safer.

What happens after detox?

Detox removes the physical dependence; staying well is separate work. Effective treatment continues with relapse prevention and aftercare, which is why Promis links detox to ongoing drug addiction treatment rather than treating detox as the finish line.

Is the detox voluntary?

Yes. Promis offers planned, voluntary treatment. We are not an acute or emergency service. If someone needs urgent or emergency help, call 999 or NHS 111.

How much does an opioid detox cost?

Cost depends on the route chosen, inpatient or supervised home detox, and the length of the plan, which is why it follows from the assessment rather than a fixed price online. The clearest next step is a confidential assessment, and you can contact us to arrange one.

Sources: NICE CG52, Drug misuse in over 16s: opioid detoxification; NHS, heroin and opioid dependence and treatment; Royal College of Psychiatrists, addiction. This article is for general information and does not replace individual medical advice.

Author: Robin Lefever, Managing Director & Therapist. Clinical review required before publication.