Paracetamol (acetaminophen) overdose: risks, symptoms and treatment

Paracetamol is a common painkiller found in many cold and flu medicines and sometimes combined with other pain relief medicines. NHS trust information explains that it is safe at the right dose, but taking too much can cause serious harm and needs medical attention. In the US and some other countries the same medicine is called acetaminophen.

An overdose can happen on purpose or by accident, for example by taking more than one product that contains paracetamol. The NHS says to avoid taking paracetamol at the same time as other medicines containing it, such as cold and flu remedies, because you may take too much, which can be dangerous.

NHS trust leaflets explain that the body breaks paracetamol down safely at normal doses, but when you take too much it becomes overwhelmed. This leads to a build-up of toxic by-products that can damage the liver and kidneys.

The NHS says taking an extra dose is unlikely to cause problems but that it can sometimes damage the liver, which is why advice should be sought. Liver damage can cause the following problems.

• Jaundice, which is yellowing of the skin and eyes.

• Itching.

• Easy bruising or bleeding.

• Swelling of the tummy.

• In severe cases, liver failure and even death, and sometimes the need for a liver transplant.

At first, hospital leaflets say you may feel sick, vomit or have tummy pain, but many people feel fine or even good in the early stages. That is the main reason medical help should be sought immediately after any overdose, even if there are no symptoms.

The Sussex leaflet lists signs that need urgent help: severe tummy pain, nausea or vomiting, yellow skin or eyes, severe headache, confusion or extreme sleepiness, and passing no urine for over 8 hours. These could mean serious liver damage. The NHS paracetamol page adds that if you are told to go to A&E you should not drive, and should bring the packet or leaflet, remaining medicine and any other medicines you take.

The NHS says to get help from NHS 111 if you have taken more paracetamol than the packet or leaflet says. If you are told to go to A&E, do not drive; ask someone to drive you or call 999 for an ambulance. Take the packet, any remaining medicine and any other medicines with you.

If someone is unconscious, has seizures, is struggling to breathe or is very drowsy, call 999 straight away. Do not wait for symptoms to appear.

Take the exact time and amount into account. NHS leaflets stress that knowing the time of the overdose is important because it helps find the risk of liver damage and whether to recommend treatment.

According to NHS trust leaflets, the team will ask what and how much was taken, when it was taken and whether any other substances, medicines or alcohol were involved, take a medical history, take blood tests and monitor vital signs such as heart rate, blood pressure and oxygen levels.

If test results show a risk to the liver, treatment is offered. Paracetamol overdose is treated with an infusion of Parvolex (N-acetylcysteine) given through a drip. It helps the body break down paracetamol safely and prevents liver damage if started early. The leaflets differ on how long the drip runs, at least 12 hours in one trust and at least 21 hours in another, so the length of your treatment will be set by the hospital team.

Parvolex can cause itching, rashes, nausea, vomiting, flushing and wheeze, and less commonly more serious allergic reactions. If this has happened before, tell staff. They can give other medicines to reduce side effects or slow the drip.

NHS trust leaflets say that if you took the overdose on purpose or need emotional support, you may be referred to the mental health liaison team before leaving hospital. One trust notes that, depending on mental state, a person is sometimes not given a choice about whether to have treatment. Teams can help create a plan for what to do if you feel so bad that you are at risk of hurting yourself again.

If you are in crisis, you can use NHS 111 and choose the mental health option, speak to your GP, or contact Samaritans. If you are in immediate danger, call 999. There is no shame in asking for help, and many people recover and go on to feel differently about their lives.

The NHS paracetamol page says to always check the packet or leaflet, leave at least 4 hours between doses and not take more than 8 500mg tablets or capsules in 24 hours. It adds that you should not take paracetamol for more than 3 days unless a doctor tells you to, and that it may not be suitable if you have a kidney or liver condition or are dependent on alcohol or binge drink.

If you weigh less than 50kg you may need a lower dose, according to the NHS. If you are unsure, ask a pharmacist or doctor.

An overdose is managed as an emergency on the NHS, through NHS 111, an emergency department or an ambulance. Antidote treatment and blood tests are provided in hospital, and a mental health liaison assessment is offered where needed.

Emergency care for an overdose is delivered through NHS routes. Follow-up with your GP afterwards is helpful for a medicines review and for support.