What are drug withdrawal symptoms, and when are they dangerous?

Symptoms start within hours to a few days, and after daily alcohol or benzodiazepines they can be life-threatening¹, as can a sudden stop of other sedatives such as mandrax or GHB.

What is withdrawal, and what do withdrawal symptoms mean?

Withdrawal symptoms mean the nervous system has adjusted to the substance being there and now has to readjust without it. It is a physical process, not a failure of willpower.

Withdrawal covers alcohol, street drugs and medicines such as opioid painkillers, benzodiazepines and pregabalin (Lyrica). For many people the substance was doing a job long before it became a problem: quieting anxiety, dulling a memory, making a hard stretch of life bearable. Stopping removes the substance but not what it was managing.

What are drug withdrawal symptoms?

What are addiction withdrawal symptoms? They range from poor sleep, irritability and cravings to seizures and delirium, and the substance decides most of where you land. The American Society of Addiction Medicine lists what makes a complicated withdrawal more likely: past seizures or delirium in withdrawal, age over 65, another illness such as a head injury, and a benzodiazepine taken alongside alcohol.

The common withdrawal symptoms that the SAMHSA detoxification guideline lists across substances are:

• sleeplessness, or sleeping far too much;
• irritability, anxiety, mood swings and low mood;
• cravings;
• sweating, shaking and a fast pulse;
• nausea, vomiting, diarrhoea and stomach cramps;
• muscle and bone aches.

Severe withdrawal symptoms are a different category: seizures, confusion, hallucinations, paranoia and delirium. For a family it often looks ordinary at first. He is short-tempered by mid-morning, sweats through the night, and the shaking only settles after the first drink. That is withdrawal, and after daily drinking it is the reason not to let him stop cold.

If someone has a seizure, becomes confused or cannot be woken, call local emergency services immediately. Do not wait for a WhatsApp reply.

Drug withdrawal symptoms by substance

Substance (local names)	When it starts and how long it lasts	What it means for you
Alcohol	6 to 24 hours after the last drink; delirium tremens at 48 to 72 hours, lasting about 1 to 8 days	Can be fatal. Do not stop after daily drinking without a detox plan
Benzodiazepines (Xanor, Valium, Ativan, Rohypnol, Serepax)	Short-acting: 1 to 2 days, for 2 to 4 weeks or longer. Long-acting: 2 to 7 days, for 2 to 8 weeks or longer	Seizure risk. Comes off by a supervised, gradual reduction
Mandrax (methaqualone, white pipe)	A sedative, and sedative withdrawal can be dangerous after a sudden stop	Treat it as a medical detox, never a cold stop
GHB	Can turn severe fast after an abrupt stop	Delirium in over half of abrupt stops without adequate treatment
Opioids and opiates (heroin, codeine, lean)	Short-acting: 8 to 24 hours, for 4 to 10 days. Methadone: 12 to 48 hours, for 10 to 20 days	Rarely life-threatening in an otherwise healthy adult, but very unpleasant; not one to stop alone
Cocaine, tik, CAT	A crash soon after the last use	Low mood and cravings; watch for suicidal thoughts
Cannabis (weed, marijuana)	Appears once regular use stops	Uncomfortable, not medically dangerous

Alcohol withdrawal symptoms

Alcohol withdrawal symptoms can start while there is still alcohol in the blood, with shaking, sweating, anxiety and poor sleep. Delirium tremens, the most severe stage, carries a mortality of up to 20%, and early identification and appropriate treatment bring it down to about 1% (review of delirium tremens⁶). The day-by-day picture is in the alcohol withdrawal timeline.

Benzodiazepine withdrawal (Xanor, Valium, Ativan)

Benzodiazepine withdrawal can bring seizures after a sudden stop, so a gradual, decreasing dose is the safest way off, according to World Health Organization guidelines⁹. Nobody should work out that reduction alone; benzo withdrawal has the detail on tapering.

Mandrax withdrawal

What is mandrax? Methaqualone, a sedative; smoked with cannabis it is called white pipe. The SAMHSA guideline groups sedative withdrawal with alcohol withdrawal as the kind that can be life-threatening, so daily white pipe is not something to stop cold.

GHB withdrawal

GHB withdrawal can turn severe fast: research into the condition¹⁰ found that abrupt withdrawal without adequate treatment leads to delirium in over 50% of cases. Like alcohol and benzodiazepines, it is not one to manage alone; our guide to what GHB is explains why.

Opioid and codeine withdrawal

Opioid withdrawal, including from codeine, is intensely unpleasant but rarely life-threatening on its own in an otherwise healthy adult, according to the SAMHSA guideline. Heroin withdrawal has the course day by day.

Cocaine, tik and CAT withdrawal

What is tik? Methamphetamine, a stimulant like cocaine and CAT. Stopping any of them, crack cocaine included, brings on a crash: exhaustion, a flat mood, broken sleep and a pull back toward the drug. The SAMHSA guideline notes that stimulant withdrawal is not usually associated with medical complications. Take the low mood seriously. Thoughts of ending your life during a crash need a professional’s attention soon, even when the crash itself is expected to pass.

If someone might harm themselves now or cannot keep themselves safe, get emergency help immediately and do not wait for a reply from us. The SADAG Suicide Crisis Helpline, 0800 567 567, is free and answers around the clock.

If you also take pills or drink, or the crash keeps pulling you back within days, talk to our team before the next attempt, or ask a relative to write to us for you. In treatment your own counsellor works with you every week on the low mood and on what keeps pulling you back to the drug.

Weed withdrawal symptoms

Weed withdrawal is real and common but not medically dangerous. A meta-analysis in JAMA Network Open pooling 23,518 people found a withdrawal syndrome in 47% of them, and NIDA lists irritability, anxiety, poor sleep, strange dreams, low appetite and depression among the symptoms. Weed withdrawal symptoms day by day sets out the timeline.

What is detoxification?

Detoxification is the set of treatments that manage acute intoxication and withdrawal and keep the body from harm while a substance clears, as the SAMHSA guideline defines it.

After daily drinking or benzodiazepines, detox is medical: monitoring, and medication where it is clinically indicated, so the brain comes down slowly instead of all at once. After cannabis or stimulants it is mostly sleep, food, routine and someone watching your mood. The same guideline says “detoxification alone is not sufficient treatment”, which is why the next step is planned before detox ends.

What are the side effects of detox?

The side effects of detox are the withdrawal symptoms it manages, usually milder: poor sleep, restlessness, low mood, cravings and some physical discomfort for the first days. Heavy drinkers often run short of thiamine, and NICE guideline CG100 advises giving it to anyone at high risk of Wernicke’s encephalopathy, a brain injury. After long benzodiazepine use, a 2025 clinical guideline notes that protracted symptoms can last for months or years, and knowing that in advance keeps people from deciding the detox failed.

Can I detox at home?

No, not after daily drinking or regular use of benzodiazepines, mandrax, GHB or sleeping tablets. Opioid and codeine withdrawal is rarely life-threatening in itself, but the same rule applies to it. In all of these cases, do not stop suddenly on your own: write to us first with what you take, how much and for how long, and we will talk through what comes next with you. The SAMHSA guideline says it is impossible to tell in advance who will develop life-threatening complications. Caught early, delirium tremens is far less deadly, and catching the early signs is what a medical team watching over a detox is for.

NICE guidance CG115 says to consider inpatient or residential withdrawal if a person drinks over 30 units of alcohol a day, scores above 30 on the SADQ dependence questionnaire, has had seizures or delirium tremens in a previous withdrawal, or needs to come off alcohol and benzodiazepines together. An assessment decides the rest. Cannabis, cocaine, tik or CAT on their own, with no pills or drink in the mix, can usually be stopped at home with support.

What is the process of detoxification?

Detoxification has three parts, evaluation, stabilisation and preparing entry into treatment, and the SAMHSA guideline calls a detox incomplete if any one is missing. Here is how each runs at Renewed Life Center in Lakeside, Cape Town.

Evaluation

Before you arrive, our counselling team carries out an assessment of 45 to 90 minutes; tell them everything you take and anything you mix it with. Dr John Wulz, our GP, has a background in mental health and emergency medicine and examines you after you arrive, and a drug and alcohol test is done on admission. You can keep taking your own medicines, such as antidepressants; the doctor reviews them.

Stabilisation

Detox is run by our medical team, from three days to two weeks depending on what your body needs. Medication is used only when clinically indicated and prescribed by a medical professional. With alcohol, the SAMHSA guideline gives medical detox one main goal: to prevent seizures and delirium tremens.

Preparing entry into treatment

Because detox alone is not enough, it leads straight into the first month. Every weekday is a full therapeutic day, and your own counsellor works with you one-to-one each week, 45 minutes at a time. Cognitive behavioural therapy, which NICE names among the psychological treatments for harmful drinking and mild alcohol dependence, works on the thinking that leads back to using. DBT gives skills for cravings and for feelings that get too big, schema therapy goes after old patterns, and for trauma we use EMDR, which NICE recommends for adults with PTSD.

Ruby Weber, our psychologist, has more than 20 years in the addictions field and leads the psychological side of our dual diagnosis work: depression, anxiety or trauma is treated in the same plan as the drinking or using, by the same team. The second month goes deeper into what the substance was covering: trauma, relationships, who you are without it. Most people stay for it. You leave with a written relapse prevention plan built for your home, and sober living and aftercare are there if going straight home is too big a step.

Planning to stop? Tell us what you take before you do. Talk to us on WhatsApp.Planning to stop? Tell us what you take before you do. Call +27 79 880 0045, free and confidential.

How do you arrange a detox with us?

It starts with one free, confidential conversation of 20 to 40 minutes by WhatsApp, video or phone, and we reply the same day. The fee depends on the programme and how long you stay; we give it on the call and send it in writing the same day. John Roberts, our Operations Manager, who has 39 years in recovery, handles first contact. Admission can be immediate and typically happens within three days of first contact. Families join a support group by video every week. Our medical detox in Cape Town page shows how the first days are run.

Detox gets you through the first days; the programme goes after the reason you were using. Contact our team on WhatsApp.

What else do people ask about withdrawal?

Does everyone who stops using need medical detox?

No. Medical detox matters most for alcohol, benzodiazepines, mandrax and GHB, where withdrawal itself can be dangerous. With cannabis or stimulants alone, stopping at home with support is usually enough, unless any of the warning signs listed above appear.

How do you quit alcohol safely if you drink every day?

Not on your own and not overnight. Do not stop suddenly; tell our team how much you drink and for how long, and we will go through the next steps with you. The full picture is on how to stop drinking alcohol.

Is it dangerous to stop more than one substance at the same time?

Yes, because the risks add up. NICE lists stopping alcohol and a benzodiazepine together among the reasons to consider inpatient withdrawal. Mixing is common: in the Western Cape, 63% of people in treatment in the second half of 2025 used more than one substance, according to SACENDU. If you use more than one, talk to our team before stopping any of them.

Does having withdrawal symptoms mean someone is addicted?

Not necessarily. The body can become physically dependent and produce withdrawal symptoms without the person meeting the wider definition of addiction, which involves compulsive use despite harm. The two often overlap.

Can withdrawal symptoms come back weeks after they seem to have passed?

Yes, for some people, most clearly after long benzodiazepine use: a 2025 clinical guideline notes that protracted withdrawal symptoms can last for months or years after the last dose.

Can a relative contact you before the person agrees to come?

Yes. A relative can talk to our team before the person has agreed to come, and relatives can have sessions of their own.