
Fentanyl Addiction Treatment at Castle Craig

Table of Contents
Key Takeaways
- Fentanyl is a potent opioid drug prescribed for medical management of severe and/or chronic pain and during operations
- Due to its high potency and effects on the brain’s reward pathways, fentanyl can be addictive, especially if used for longer than three months
- Fentanyl is a controlled, Class A drug in the UK but illegal, non-medical forms are made which can contain other drugs like heroin or cocaine
- Fentanyl use can result in side effects such as confusion, hallucinations and breathing issues
- Pinpoint pupils, unconsciousness and breathing difficulties are key signs of fentanyl overdose which represents a medical emergency requiring immediate treatment
- Fentanyl misuse can lead to addiction, which occurs when a person becomes physically dependent, loses control over use, performs risky behaviours and/or experiences social issues as a result of fentanyl use
- Addiction to fentanyl, also known as fentanyl use disorder, is a medical condition requiring appropriate medical and therapeutic interventions
- A combination of medical, counselling and behavioural therapies is often most effective in managing fentanyl addiction
Fentanyl is one of the only painkillers that can be prescribed long-term, furthering the possibility of addiction.
What is Fentanyl?
Fentanyl can be addictive and prolonged use, i.e., longer than 3 months, is associated with increased risk of addiction and dependence. For this reason, healthcare professionals are advised to discuss these risks with patients and provide them with information on overdoses, deliver regular monitoring and communicate a plan for use and discontinuation of treatment. Withdrawing from fentanyl can take weeks or months as doses should be slowly tapered to help avoid withdrawal symptoms.2
Prescription opioids like fentanyl are typically prescribed by specialists for relief of severe pain, chronic pain or for use in operations. It is available in various forms for medical use; lozenges, patches, nasal spray and injections. In these environments, fentanyl may also be known as Actiq, Duragesic or Sublimaze.1–3
Medical fentanyl can start working in around 15–30 minutes when taken in lozenge, tablet or nasal spray form and can remain effective for 4–6 hours. Fentanyl patches last longer; up to 72 hours (3 days).1,2
Like other opioids, fentanyl works by binding to opioid receptors in the brain. These receptors are located in areas of the brain responsible for control of pain, emotions and reward.
Fentanyl use can therefore lead to feelings of extreme happiness and pain relief. It can also have other effects, which can be dangerous:
- Confusion
- Drowsiness or sedation
- Difficulty breathing
- Unconsciousness
Fentanyl Addiction
Fentanyl is a highly potent analgesic drug that is approximately 50–100 times more potent than morphine. Although it is prescribed for medical use, it can also be produced and used illegally. Illegal fentanyl comes in various forms, including powder, eye drops, nasal sprays and tablets, and can be mixed with other drugs like heroin or cocaine.3
In the UK, under the Misuse of Drugs Act 1971, fentanyl is a controlled, Class A drug. This means that it is illegal to manufacture, supply or possess non-medical fentanyl in the UK. In circumstances where fentanyl has been illegally produced, supplied or possessed, unlimited fines, prison sentences or both can be enforced.4,5
Due to its potency and its effects on the brain, particularly in raising dopamine levels in reward pathways, fentanyl can be addictive, in both medical and non-medical (i.e., illicit) formulations.3,6

Diagnosing Fentanyl Addiction
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is a widely-used tool for recognising and diagnosing mental health conditions and addictions. It contains criteria for diagnosing addictions, also known as substance use disorders (SUDs), and recognises opioid use disorder as a condition resulting from opioid use.
The DSM-5 criteria for substance use disorders (SUDs) features 11 parameters and is used to aid diagnosis of opioid use disorders, such as fentanyl use disorder. These parameters describe the impaired control, dependence, social issues and risky use that can come with fentanyl addiction.
The criteria for diagnosing fentanyl use disorder are:
- Inability to reduce or stop fentanyl use
- Using more fentanyl or using it for longer than intended
- Experiencing cravings
- Investing significant amounts of time in obtaining, using or recovering from fentanyl use
- Inability to maintain usual responsibilities at home, work or school due to fentanyl use
- Neglecting important work, social or hobby activities due to fentanyl use
- Repeated use despite dangerous consequences
- Continued use despite relationship issues
- Continued use despite physical or psychological issues that could be caused or exacerbated by fentanyl use
- Development of tolerance, i.e., requiring higher doses to achieve the desired effect
- Experiencing withdrawal symptoms that are alleviated by fentanyl use
The presence of two or more of these symptoms indicates the presence of fentanyl use disorder, a type of substance use disorder (SUD). The severity of the disorder is graded according to the number of symptoms experienced. A mild SUD usually features 2–3 symptoms, a moderate SUD has 4–5 symptoms and a severe SUD generally features 6 or more symptoms.7

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Risk Factors for Developing Fentanyl Addiction
There are various factors which can increase the risk of opioid use disorders, including fentanyl addiction. These include:8
- Adversity in childhood
- History of preadolescent sexual abuse
- Personal and/or family history of substance misuse
- Previous substance misuse treatment
- Previous legal issues
- Lack of adequate social support
- Psychological conditions, trauma or stress
- History of pain with unclear cause, increasing severity and/or which limits function
- Stress resulting from uncontrolled pain
- Young age
- Preoccupation with opioids
- Psychotropic substance use
Signs and Symptoms of Fentanyl Addiction
Fentanyl use can lead to pain relief and feelings of euphoria and relaxation, however, it can also have various side effects, including:2,9
- Drowsiness
- Dry mouth
- Difficulty urinating
- Difficulty sleeping
- Dizziness
- Confusion
- Hallucinations, i.e., sensing something that isn’t really there
- Heart palpitations
- Abnormal heart rhythms
- Difficulty breathing
With long-term use, a person’s brain gets used to the presence of fentanyl. This can lead to a reduction in reward from sources other than fentanyl use. Over time, fentanyl use can result in:9
- Mood swings
- Breathing issues
- Constipation
- Decreased sex drive
- Menstrual cycle problems
In addition to these signs and symptoms, the DSM-5 criteria outline social, occupational and personal issues that can arise as a result of fentanyl addiction. These are also important to consider when recognising and managing these conditions, picturing objects, or people that aren’t in front of them.
Fentanyl Withdrawal
Individuals suffering from fentanyl use disorder, or fentanyl addiction, who abruptly stop using the substance can experience severe withdrawal symptoms. These effects can start a few hours following the last use and can include physical and/or psychological symptoms.3
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Physical Symptoms
Physical signs and symptoms of fentanyl withdrawal include:
- Pain in muscles and/or bones
- Vomiting
- Diarrhoea
- Sweating
- Shaking
- Goosebumps on the skin
- Spontaneous leg movements
- Sleep disturbances
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Psychological Symptoms
Fentanyl Overdose
In the US, fentanyl and other synthetic opioid drugs are among the most common drugs involved in fatal drug overdoses. The high potency of fentanyl increases the risk of overdose. In addition, illicit fentanyl poses a significant risk of overdose as its components are not always known by the user.
An overdose occurs when fentanyl use produces severe, life-threatening symptoms and signs. These can progress from reduced or absent breathing (also known as respiratory depression) to coma, permanent brain damage and death3
Fentanyl use, addiction and relapse following abstinence are all risk factors for overdose.10
Management of Fentanyl Overdose
Opioid overdoses represent medical emergencies that require immediate intervention. These events can be fatal, so understanding the appropriate actions can save lives.
If fentanyl overdose is suspected, you should look to identify the three common signs of overdose: breathing difficulties, pinpoint pupils and unconsciousness.
Once confirmed, you should call emergency services immediately and administer naloxone, which can reverse the effects of overdose if given in time. Providing basic life support and reassurance until help arrives will also help someone through an overdose event.11
Following overdose, the person should receive relevant medical and psychological support to aid long-term recovery.10
If you are searching for guidance to support a friend or family member in crisis, please call the emergency services. The information on this page is not intended as a substitute for medical intervention.
Learn more about the management of opioid overdoses.
Treatment for Fentanyl Addiction
As with other opioid use disorders, effective management of fentanyl addiction typically involves a combination of medical and behavioural therapies.
Medical Treatments
There are three FDA-approved medications which can be used in the management of fentanyl addiction and other opioid use disorders. These drugs act on the same receptors as fentanyl without producing its effects.
These medications are:
- Methadone: An opioid which binds to opioid receptors in the brain, thus preventing fentanyl from binding. This prescription medication can help ease cravings and withdrawal symptoms but has the potential for misuse and addiction
- Buprenorphine: An opioid which partially activates opioid receptors in the brain to alleviate cravings and withdrawal symptoms. Again, as this drug is an opioid, its use carries addictive potential
- Naltrexone: A non-opioid medication which prevents fentanyl from binding to opioid receptors in the brain. As fentanyl is unable to bind to receptors, its effects are blocked
The treatment doses of opioids, methadone and buprenorphine, will not produce feelings of euphoria in people living with fentanyl use disorder, as they have developed tolerance to opioids. These medications can help to control withdrawal symptoms and promote recovery. People living with opioid use disorders can use these medications long-term if needed to manage their condition.3,10
Counselling and Behavioural Therapies
There are several therapies which can be used in the management of fentanyl addiction and other opioid use disorders. These approaches are often combined with medical treatments and include:
- Cognitive behavioural therapy (CBT): A form of psychotherapy which examines the interplay between thoughts, emotions and behaviours. This approach can generate positive behaviours and foster effective responses to stressors or triggers
- Motivational interviewing: A person-centred counselling approach where counsellors encourage individuals to explore their emotions and take responsibility for their behaviours. This can help build self-motivation and prepare individuals to be more receptive to treatment 12
- Motivational enhancement therapy: Similar to motivational interviewing, this approach strives to build motivation and dedication to addressing fentanyl use disorder
- Contingency management: This form of treatment involves using vouchers or rewards to encourage positive behaviours, such as sobriety
- Family counselling: This holistic approach helps individuals and their families to explore and understand the widespread impacts of fentanyl addiction. This can be effective in building social support, which is important during addiction recovery
- Mutual support groups: These groups provide a non-judgemental space for giving and receiving support during recovery from fentanyl addiction. Groups such as SMART Recovery and Narcotics Anonymous foster encouragement and accountability which can have positive impacts on an individual’s recovery journey
There is no one-size-fits-all approach to substance use disorder treatment. Communicating your needs and preferences is an important step for developing a personalised treatment plan which can promote long-term recovery.3,7,10
Castle Craig provides an inclusive, caring environment that promotes whole well-being throughout the recovery process.

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How Can Castle Craig Help?
Castle Craig offers world-renowned addiction treatment services. We have experience in treating a range of addictions, including fentanyl addiction.
At Castle Craig, we offer an integrated programme for addiction to fentanyl medications, such as Actiq, Duragesic and Sublimaze. Treatment plans are developed for each patient and each patient will work through their treatment plan with their therapist.
Our medically supervised detox promotes patient safety and comfort. Our primary aim is to help patients feel comfortable and at ease, with round-the-clock care.
Castle Craig provides an inclusive and caring environment that promotes well-being throughout the recovery process.
Our treatment is evidence-based and is effective in our patient outcomes studies. An independent review highlighted that 91.8% of those followed-up from our 2015 cohort demonstrated improvement after 1 year. 73.4% were abstinent at 1 year following treatment at Castle Craig.15
Alongside a supervised medical detox and personalised treatment plan, Castle Craig works to address emotional and psychological issues that may have contributed to fentanyl misuse. Getting to the route of opioid addiction can be an important step in reducing the risk of relapse. We will work with you to develop new, positive strategies for navigating these challenges in recovery.
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Don’t Suffer Alone. Our Friendly Team Are Waiting to Help You Start Your Recovery Journey.
Beginning Your Journey to Recovery
Addiction is a challenging experience for an individual and those around them. Castle Craig recognises how scary it can be to seek help and we pride ourselves on providing an entirely non-judgemental environment. Our staff deliver the highest standards of support and care, as they are trained and equipped to focus on more than just addiction, providing a holistic approach to your recovery and aftercare.
If you are suffering from fentanyl addiction, or know someone who is, please get in touch to find out how you can begin your journey to recovery.
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References
- National Health Service (NHS). Fentanyl.
- National Institute for Health and Care Excellence (NICE). Fentanyl.
- National Institute on Drug Abuse. Fentanyl DrugFacts.
- National Institute for Health and Care Excellence (NICE). Controlled drugs and drug dependence.
- GOV.UK. Drugs penalties.
- Ramos-Matos CF, Bistas KG, Lopez-Ojeda W. Fentanyl. Treasure Island (FL).
- Hartney E, Gans S. DSM 5 Criteria for Substance Use Disorders: How substance use disorders are diagnosed.
- Webster L. Risk Factors for Opioid-Use Disorder and Overdose. Anesthesia & Analgesia.
- Ellis RR, Begum J. Fentanyl: What You Need to Know.
- Yale Medicine. Opioid Use Disorder.
- World Health Organization (WHO). Opioid overdose.
- Hartney E, Umhau JC. Understanding Motivational Interviewing.
- SMART Recovery. The SMART Recovery Programme.
- Narcotics Anonymous in the United Kingdom (UKNA). Welcome to UKNA.
- Barnes, O. A Review of Evidence Supporting Castle Craig’s Treatment Programme. The Castle Craig Pamphlet Series. 2016:1–24.
- Scottish Government. Residential rehabilitation: literature review.