Synthetic opioids

Synthetic opioids are man-made drugs that act like natural opioids such as heroin or morphine, but are often much stronger and more dangerous. Some are prescribed legally for pain relief, while others are made illegally and sold on the street.

Because of their strength, synthetic opioids are linked to a high risk of overdose, particularly when people do not realise they are taking them.

Names you might hear

Across the UK and North West, synthetic opioids may be known as:

  • Fentanyl

  • Nitazenes

  • Tramadol

  • Oxycodone

  • Carfentanyl

They are often found mixed into other drugs, especially heroin, which significantly increases overdose risk.

What do synthetic opioids look like?

Synthetic opioids can appear in many forms, including:

  • Tablets or capsules

  • Powders

  • Liquids

They are often:

  • White or off-white powders

  • Coloured tablets

Medically prescribed versions come in clearly labelled packaging. Illicit versions may be sold in unmarked bags or disguised packaging, making it impossible to know what they contain or how strong they are.

What do they smell or taste like?

Most synthetic opioids have:

  • Little or no smell

  • A bitter or chemical taste

Trying to taste or smell drugs to identify them is very dangerous and can lead to accidental overdose.

How do people use synthetic opioids?

Synthetic opioids may be used in similar ways to other opioids:

  • Swallowed

  • Snorted

  • Injected

  • Heated and inhaled

Injecting greatly increases the risk of overdose, vein damage, infections and blood-borne viruses.

How synthetic opioids can make you feel

The effects are similar to other opioids and may include:

  • Pain relief

  • Feelings of wellbeing or euphoria

  • Relaxation

  • Drowsiness or sleepiness

At higher doses, people may:

  • Lose consciousness

  • Stop breathing

People may also experience sweating, itching, nausea or vomiting.

How long the effects last

How long synthetic opioids last depends on:

  • The specific drug

  • The amount taken

  • Your body and tolerance

  • Whether other substances are used

Some synthetic opioids act very quickly and powerfully, increasing the risk of overdose.

Physical health risks

Synthetic opioids suppress breathing. This can lead to:

  • Respiratory arrest (stopping breathing altogether)

  • Loss of consciousness and coma

  • Death

Other risks include:

  • Dizziness or fainting

  • Severe withdrawal symptoms

  • Itching

  • Lethargy

  • Constipation

Injecting synthetic opioids can cause:

  • Severe vein and artery damage

  • Blood clots

  • Gangrene

  • Serious infections

Sharing injecting equipment increases the risk of hepatitis B, hepatitis C and HIV.

Mixing synthetic opioids with other substances

Mixing drugs always increases risk.

Mixing synthetic opioids with:

  • Alcohol

  • Benzodiazepines such as diazepam, Valium or Xanax

  • Other opioids such as heroin

greatly increases the risk of fatal overdose.

Synthetic opioids such as fentanyl and nitazenes are often found mixed into heroin, meaning people may take them without knowing.

White heroin can also be mistaken for cocaine. People have been hospitalised and have died after accidentally snorting heroin.

Synthetic opioids and naloxone

Overdoses involving synthetic opioids are extremely dangerous due to their strength.

Naloxone is a life-saving medication that temporarily reverses the effects of an opioid overdose and buys time for emergency help to arrive.

If you use opioids, or know someone who does, you should carry naloxone.

You can get a free naloxone kit from Wirral Ways. Just ask a member of staff at one of our hubs.

Naloxone saves lives.

Dependence and addiction

Synthetic opioids are highly addictive.

With repeated use, people can develop:

  • Tolerance, needing more to get the same effect

  • Physical dependence

  • Strong cravings

Stopping suddenly can cause severe withdrawal symptoms.

Social risks

Ongoing use of synthetic opioids can also affect:

  • Relationships and family life

  • Physical and mental health

  • Housing and employment

  • Finances, sometimes leading to crime to fund use

Support can help address these wider impacts.

The law

Most synthetic opioids are Class A drugs.

This means:

  • It is illegal to possess them without a prescription

  • It is illegal to give them away or sell them

Penalties can include:

  • Up to 7 years in prison for possession

  • Life imprisonment and unlimited fines for supply

Driving while under the influence is illegal and dangerous.

Staying safer

If someone is using synthetic opioids:

  • Avoid mixing with alcohol or other depressant drugs

  • Avoid injecting

  • Use with others around, not alone

  • Carry naloxone and make sure others know how to use it

If someone is unconscious, breathing slowly, or not breathing at all, call 999 immediately and use naloxone if available. Seeking medical help will not get you into trouble.

Support from Wirral Ways

Wirral Ways offers free, confidential support for people affected by synthetic opioid use, as well as support for families and carers.

We can help with:

  • One-to-one support

  • Harm reduction advice

  • Naloxone kits and training

  • Support to reduce or stop safely

  • Mental and physical health support

  • Help with housing, benefits and wider wellbeing

Support is tailored to you and your goals.

Worried about someone else?

If you are worried about a friend or family member, you can contact us for advice and support. You do not have to manage this alone.

Get support

You can contact Wirral Ways to access support:

  • Self-refer online

  • Speak to a member of our team

  • Visit one of our services

Support is available, and help is there when you’re ready.

Last Updated on 4 February 2026