Withdrawal symptoms can start anywhere from a few hours to several days after your last dose, depending on the substance. Fast-acting drugs like heroin and nicotine produce symptoms within hours, while longer-acting substances like certain anxiety medications may not trigger noticeable withdrawal for days. The speed of onset comes down to how quickly the substance leaves your system and how dependent your body has become.
Alcohol Withdrawal
Mild alcohol withdrawal symptoms typically appear 6 to 12 hours after your last drink. These early signs include headache, mild anxiety, insomnia, nausea, and shakiness. For people with heavy, prolonged use, the timeline escalates from there.
Hallucinations can develop within 24 hours. Seizure risk peaks between 24 and 48 hours after the last drink. The most dangerous stage, delirium tremens, can appear 48 to 72 hours later, bringing confusion, rapid heart rate, fever, and severe agitation. Even with intensive medical care, delirium tremens carries a mortality rate of 5 to 15%. Before modern ICU treatment existed, that figure was as high as 35%. This is why heavy drinkers should never quit abruptly without medical supervision.
Opioid Withdrawal
The onset of opioid withdrawal depends heavily on whether the drug is short-acting or long-acting. Heroin withdrawal begins 6 to 12 hours after the last use and typically lasts about five days. Other short-acting opioids and injected forms follow a similar pattern: rapid onset, intense but relatively brief.
Long-acting opioids like methadone take longer to leave the body, so withdrawal starts later, sometimes not until 24 to 48 hours or more after the last dose. The tradeoff is that these withdrawals tend to be less intense hour by hour but drag on for a longer total duration. Early symptoms for any opioid include muscle aches, restlessness, watery eyes, and anxiety, followed by cramping, diarrhea, nausea, and insomnia as withdrawal progresses.
Benzodiazepine Withdrawal
Benzodiazepines used for anxiety and sleep (like alprazolam, diazepam, and lorazepam) vary widely in how quickly withdrawal hits. Short half-life drugs clear your system faster, so symptoms can begin within one to two days of stopping. Longer half-life drugs may not produce noticeable withdrawal for up to a week. Overall, the withdrawal window spans roughly 1 to 7 days for onset and can last 4 to 14 days depending on which drug you were taking.
Benzodiazepine withdrawal can be medically serious, particularly after long-term use. Symptoms include rebound anxiety, insomnia, tremors, and in severe cases, seizures. Gradual tapering under medical guidance is the standard approach for this reason.
Nicotine Withdrawal
Nicotine withdrawal is one of the fastest to appear. Symptoms begin 4 to 24 hours after your last dose if you’ve been a regular user. Cravings, irritability, difficulty concentrating, and increased appetite are the hallmark early symptoms. The physical withdrawal typically peaks within the first few days and gradually fades over two to four weeks, though cravings can persist much longer.
Stimulant Withdrawal
Cocaine and methamphetamine produce a distinctive “crash” phase that begins within hours of the last use and lasts roughly 24 to 72 hours. During the crash, you feel extreme fatigue, increased appetite, depressed mood, and a strong need for sleep. It’s the body’s immediate response to losing the flood of activity these drugs produce in the brain.
Unlike alcohol or opioid withdrawal, the stimulant crash is followed by a longer subacute phase spanning weeks 2 through 4, during which some symptoms improve while others, particularly low mood and difficulty feeling pleasure, can persist or even intensify before gradually resolving.
Cannabis Withdrawal
Cannabis withdrawal is a recognized condition for heavy, long-term users. Symptoms usually begin within 24 to 48 hours of stopping and peak around day three. Irritability, sleep disturbance, decreased appetite, restlessness, and cravings are the most common complaints. Most symptoms resolve within one to two weeks.
Antidepressant Discontinuation
Stopping antidepressants, particularly SSRIs and SNRIs, can produce discontinuation symptoms that emerge within days to weeks of stopping or lowering the dose. Symptoms typically start once 90% or more of the drug has cleared your system, which varies by medication. Common experiences include dizziness, “brain zaps” (brief electric shock sensations), nausea, irritability, and flu-like feelings. Tapering slowly rather than stopping abruptly reduces the risk significantly.
What Affects How Quickly Symptoms Start
Two people using the same substance can have very different withdrawal timelines. Several factors explain why:
- The specific drug’s duration of action. Longer-acting drugs produce a slower, more drawn-out withdrawal. Shorter-acting drugs hit faster and harder.
- How much you used daily. Higher daily amounts lead to more severe withdrawal symptoms.
- How long and how regularly you used. For opioids, clinically significant withdrawal usually doesn’t appear until someone has used daily for two to three weeks. Severity increases with duration of regular use up to about two to three months, after which it plateaus. Intermittent use produces less severe withdrawal than daily use.
- Psychological factors. Your mental state, personality, and even how anxious you are about withdrawal itself can influence how intensely you experience symptoms.
Your metabolism, age, liver function, and overall health also play a role. Someone with a faster metabolism will clear a drug more quickly, potentially experiencing earlier onset of symptoms. People using multiple substances may face overlapping withdrawal timelines that complicate the picture further.
Quick Reference by Substance
- Alcohol: 6 to 12 hours
- Heroin and short-acting opioids: 6 to 12 hours
- Long-acting opioids (methadone): 24 to 48+ hours
- Nicotine: 4 to 24 hours
- Stimulants (cocaine, meth): within hours (crash phase)
- Cannabis: 24 to 48 hours
- Short half-life benzodiazepines: 1 to 2 days
- Long half-life benzodiazepines: up to 7 days
- Antidepressants: days to weeks