Opioid overdose: signs, naloxone and what to do

Opioids are a group of drugs that includes prescription painkillers such as morphine and methadone, and street drugs such as heroin. UK Government guidance on naloxone describes the main life-threatening effect of heroin and other opiates or opioids as slowing down and stopping breathing. An overdose happens when the amount taken, alone or combined with other substances, is enough to produce that dangerous slowing of breathing.

FRANK, the UK government drugs information service, says it is very easy to overdose from heroin, which kills far more people in the UK than any other illegal drug. The same service notes that if you have taken heroin regularly you may have built up some tolerance, but if you stop for even a few days your tolerance will fall, so a dose that was once usual can become dangerous.

FRANK says that if you overdose you may begin to feel very sleepy, your breathing will slow and you can fall into a coma. If breathing slows too much, you could die. The guidance on naloxone says training for those who may need to respond includes how to identify a possible opioid overdose.

Because the person may be unable to ask for help, the signs are often noticed by someone else. The sources read do not give a full checklist of every sign, so the simplest rule is to treat unusual sleepiness, very slow or shallow breathing or being unable to wake someone who has taken opioids as an emergency.

UK Government guidance says people being given naloxone are trained in the importance of calling 999, or getting someone else to call, and asking for an ambulance. They should let the call handler know they have naloxone and have been trained to use it, follow their instructions, and know how to unpack, assemble and give the product.

The guidance also stresses staying with the person who has overdosed, being ready to tell the ambulance what they have taken if you know and how much naloxone you have given. Naloxone does not replace the ambulance: the guidance’s training points are built around calling 999 and staying with the person.

FRANK lists the main risks: overdose and death risk is high, mixing heroin with other downers including methadone, alcohol and benzodiazepines is extremely dangerous, and heroin is highly addictive so people may become dependent and need more to get the same effect. It adds that injecting can be very dangerous and can lead to overdose.

The guidance on naloxone lists people who might be at risk of overdose and who may be supplied with naloxone, together with their family members and friends, and outreach workers for homelessness services whose clients include people who use opioids.

The guidance explains that naloxone is a prescription-only medicine, so pharmacies cannot sell it over the counter, but drug treatment services and others can supply it without a prescription if they are making it available for the purpose of saving lives. Under regulations updated in 2015, 2019 and 2024, those who can supply it include people working for drug treatment services, police forces, prison and probation services, registered nurses and midwives, pharmacists and pharmacy technicians, and registered paramedics.

They can supply take-home naloxone, or naloxone to be carried in case it is needed, in nasal or injectable forms, as long as they are suitably trained. Take-home naloxone can be given to a person at risk, a family member or friend, or an outreach worker. Ask your drug service, GP or pharmacy whether take-home naloxone is available in your area.

Opioid dependence can be treated, and the NHS notes that regular users of heroin or other opioids who are pregnant should not stop or reduce the amount without speaking to a doctor first, because it is important to withdraw from these drugs in the right way to reduce risk to the mother and baby. It lists help from a midwife, GP or drug treatment services, which it says will not judge you.

FRANK offers confidential drugs advice. If you are worried about someone, you can ask a GP or local drug service about treatment options and about carrying naloxone. Support for opioid use disorder usually combines medicines, which are not described in detail in the sources read, with psychological and social support.

An opioid overdose is an emergency managed through 999 and NHS emergency care. Naloxone supply, and treatment for opioid dependence, is generally delivered through NHS-commissioned or local authority drug treatment services and primary care.

Private addiction services also exist, but they are not part of the emergency response. Whichever route is used, ask how your care will be coordinated with your GP and how naloxone will be provided for you and the people around you.