Overdose or Poisoning: What to Do Before the Ambulance Arrives

If you think someone has taken too much of a medicine or drug, or swallowed or breathed in something poisonous, get help at once — don't wait for symptoms. Until help arrives, breathing is what matters: no response and no normal breathing — start CPR; unconscious but breathing normally — on their side. Don't make them vomit.

When to see a doctor

Right away, call an ambulance — 999 in the UK, 911 in the US, 112 in the EU:

they don't respond or are hard to wake; breathing is slow, shallow, irregular, noisy — gurgling, snoring — or has stopped; lips or nails are blue or grey; they have a seizure (NHS; CDC);
the overdose was deliberate — even if they say they feel fine;
UK: the NHS says call 999 or go to A&E whenever you think someone has swallowed or breathed in something harmful. US: if they are awake and breathing normally, Poison Help (1-800-222-1222) can say whether hospital is needed.

Today — by phone, even without symptoms:

you are unsure whether a substance is dangerous: UK — NHS 111; US — Poison Help 1-800-222-1222, free and 24/7 (NHS; HRSA);
extra paracetamol — more than the pack allows, including extra doses spread over a day or two, or two products that both contain it. UK — NHS 111 or A&E, and don't drive yourself to A&E (NHS); US — Poison Help. The point everywhere is the same: today, not when symptoms appear.

Afterwards: after a deliberate overdose, a mental health assessment should happen before the person leaves hospital (NICE NG225, UK). Crisis support alongside it: in the UK Samaritans on 116 123, in the US 988.

What to do before help arrives

Check response and breathing. No response and no normal breathing — occasional gasps are not breathing: tell the call handler and start CPR as they instruct (basic CPR). If you are trained, give rescue breaths as well as compressions (AHA).
Unconscious but breathing normally: put them on their side in the recovery position so they don't choke, and keep checking. If breathing stops being normal, start CPR (NHS).
Awake: keep them with you, give nothing to eat or drink (NHS).
Don't make them vomit — no fingers down the throat, salt water or ipecac syrup (NHS; Poison Control, US).
Find the packaging or the substance and give it to the paramedics; if they have vomited, keep a sample (NHS).
Tell the call handler what was taken — the name and ingredients — how much, when, the person's age and weight, and how they are now (Poison Help; NHS).
Stay with them until help arrives. Cold showers, coffee, walking them around or letting them sleep it off don't remove the substance.

What is happening

Breathing is the main danger. Opioids slow and stop breathing; alcohol combined with sleeping pills, sedatives or opioids depresses it too (CDC; NIAAA).

Why gasping is not breathing. Noisy, irregular gasps in someone who is unconscious can be a sign that the heart has stopped — they need chest compressions, not the recovery position (British Red Cross). Only people who are breathing normally go on their side.

Why not induce vomiting. A drowsy person can choke on vomit (NHS).

Why paracetamol is treacherous. At first people often feel normal; nausea, vomiting or stomach pain may appear or may not. Meanwhile the liver is being damaged. An antidote prevents this if it is started early and works best in the first hours; later come jaundice, liver failure, sometimes a transplant or death (University Hospitals Sussex NHS). Extra doses over a day or two are no safer than one large dose; since 2012 the UK treats them with the antidote regardless of the blood level (MHRA). Why it is easy to take too much without noticing: same ingredient under different brand names and paracetamol vs ibuprofen.

Opioids and naloxone

Signs (CDC, US): unconscious or can't be woken; slow, shallow or no breathing, choking, gurgling or snoring sounds; changed skin colour, especially lips and nails; pinpoint pupils.

Naloxone reverses an opioid overdose. If you have it, give it and call for help (CDC); call right after the first dose. If the person is not breathing normally, CPR comes first; give naloxone if it does not delay CPR or the call (AHA).
It won't harm someone whose overdose was not caused by opioids, so if in doubt, give it (CDC).
It does not replace the ambulance. More than one dose may be needed, especially with fentanyl (CDC), and it can wear off before the opioid does, so the overdose can return (NIDA). Stay with them.
Where to get it. US: sold without a prescription since 2023 (FDA) and available in every state (CDC). UK: a prescription medicine, but drug services and needle exchanges give out take-home naloxone free of charge, and since December 2024 so can trained police, ambulance, prison and probation staff (GOV.UK); it is not on open sale in pharmacies.
Fear of calling. Most US states have laws that partly protect a person who calls for help in an overdose, with exceptions (GAO). Call anyway: for someone who has stopped breathing, minutes count.

Alcohol has its own signs of poisoning and its own list of what not to do: how alcohol leaves the body.

When this is not the case

Children: a swallowed button battery is a separate emergency — what to do; iron tablets are dangerous for small children — supplements without a test.
Household chemicals and fumes: never mix bleach with ammonia or vinegar.
Keep the numbers at hand: save emergency numbers now.

Sources

Checked: 27 September 2026