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Opioid misuse and dependence

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Strong painkillers article more useful, or one of our other health articles.

Opioids are either derived from naturally occurring opium (eg, heroin) or are made synthetically (eg, methadone, buprenorphine).1 If used continuously, they have the potential for causing both physical and psychological dependence within 2-10 days.2

Opioids have two main effects: an analgesic effect and a euphoric effect. Their euphoric effect is the reason why they can be misused. They can be used intravenously (IV), subcutaneously and intranasally or smoked. Remember that if someone reports opioid misuse, they may also be abusing other drugs.

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What is opioid dependence?

Characteristic features include drug craving and maladaptive behaviour focused on obtaining opioids at any cost. Opioid misuse can be defined as a continuous compulsion to use opioids despite physical, psychological or social harm to the user.3

The Eleventh Revision of the International Classification of Diseases and Health Problems (ICD-11) states that the following are required for the diagnosis of opioid dependence:4

A pattern of recurrent episodic or continuous use of opioids with evidence of impaired regulation of opioid use that is manifested by two or more of the following:

  • Impaired control over opioid use (onset, frequency, intensity, duration, termination, context).

  • Increasing precedence of opioid use over other aspects of life, including maintenance of health, and daily activities and responsibilities, such that opioid use continues or escalates despite the occurrence of harm or negative consequences (eg, repeated relationship disruption, occupational or scholastic consequences, negative impact on health).

  • Physiological features indicative of neuroadaptation to the substance, including: 1) tolerance to the effects of opioids or a need to use increasing amounts of opioids to achieve the same effect; 2) withdrawal symptoms following cessation or reduction in use of opioids, or 3) repeated use of opioids or pharmacologically similar substances to prevent or alleviate withdrawal symptoms.

The features of dependence are usually evident over a period of at least 12 months but the diagnosis may be made if use is continuous (daily or almost daily) for at least 3 months.

How common is opioid dependence? (Epidemiology)1

The prevalence of drug dependence varies with age, sex, employment status and ethnicity.

  • It is more common in men (4.3%) than women (1.9%) and highest in men aged 16-24 years (11.8%).

  • In men, signs of drug dependence are most common in those described as economically inactive (9.6%). For women, the highest prevalence is also found in those who were unemployed (4.4%).

  • The proportion of people showing signs of drug dependence (for drugs other than cannabis) in the last year was:

    • 1.9% in Black/Black British people.

    • 1.1% in Asian/Asian British people.

    • 0.8% White British people.

    • 0.6% White other people.

In 2017/18 268,390 individuals were in contact with drug and alcohol services in England, with the largest proportion of them (53% or 141,189 people) in treatment for opioid dependence.

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Acute opioid withdrawal symptoms1

The clinical features of acute withdrawal syndrome include:

  • Watering eyes, rhinorrhoea, yawning, sneezing, cool and clammy skin, dilated pupils, cough.

  • Abdominal cramps, nausea, vomiting, diarrhoea.

  • Tremor, sleep disorder, restlessness, anxiety, irritability, hypertension.

Untreated heroin dependence shows early withdrawal symptoms within 8 hours, with peak symptoms at 36–72 hours. Symptoms subside substantially after 5 days. Cravings can last for up to six months. Methadone hydrochloride or buprenorphine withdrawal occurs later, with longer-lasting symptoms. Methadone withdrawal symptoms can take 10-12 days to subside.5

Complications due to opioid dependence1

Health problems

  • Death (which may be due to overdose, suicide, accidents or health-related complications).

  • Skin infection at injection sites (can be severe; necrotising fasciitis can occur).

  • Sepsis.

  • Infective endocarditis.

  • HIV infection.

  • Hepatitis A, B and C infection.

  • Tuberculosis infection.

  • Venous and arterial thrombosis (due to poor injecting techniques).

  • Poor nutrition and dental disease.

Social problems

  • Crime.

  • Relationship problems.

  • Child protection issues.

  • Homelessness and deprivation.

  • Working in the sex industry.

Psychological problems

  • Craving.

  • Guilt.

  • Anxiety.

  • Loss of cognitive skills and memory.

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Presentation in primary care1

Someone who is opioid-dependent may present to primary care in a number of different ways, including:

  • An active request for help with drug dependency or alcohol dependency.

  • A complication of drug use (see 'Complications' section above).

  • Clinical features of opioid intoxication, which include constriction of pupils, itching and scratching, sedation and somnolence, lower blood pressure, slower pulse, hypoventilation.

  • Acute withdrawal syndrome (see 'Acute opioid withdrawal symptoms' section above).

  • Psychiatric history of overdoses, depression, psychosis.

  • Forensic history of past custodial sentences, probation, community service.

  • Social history of family problems, unemployment, accommodation issues, financial problems.

  • Evidence of poor nutrition, dental caries, other signs of neglect, needle tracks, skin abscess, and signs of drug intoxication or withdrawal.

  • Indications of abnormal general behaviour, disorders of mood (particularly anxiety or low mood), delusions or hallucinations, confusion.

Provision of care for opioid misusers

  • All GPs have a duty to provide basic medical services to people who are dependent on opioids and they should screen patients for drug misuse.

  • If detoxification and/or substitute prescribing are requested, after an initial assessment, GPs can refer to local specialist community drug services and there are usually locally agreed shared care guidelines. A care plan between the drug misuser and the service provider can then be drawn up.

  • A GP may have a special clinical interest in the management of substance misuse in primary care and may be able to take more responsibility in the treatment of patients, particularly in complex cases.

  • A multidisciplinary approach to care is needed.

  • Strict practice policies surrounding the care of drug misusers are advised.

  • There are UK guidelines for drug misuse and dependence, produced by the Department of Health (England), the Scottish Government, the Welsh Assembly Government and the Northern Ireland Executive. Further information can be found in the separate Drug Misuse and Dependence UK guidelines article.

Assessment of someone presenting with opioid misuse or dependence1

  • The assessment of someone with drug dependence is discussed in detail in the separate Assessment of Drug Dependence article.

  • Details about the nature of drug and alcohol misuse should be determined.

  • Appropriate history and examination should be carried out, including a mental state examination.

  • Drug testing should be performed to confirm opioid misuse.

  • Assessment of risk and social functioning should be carried out.

  • Investigations to exclude complications, such as:

    • Tests for hepatitis B, and C, and HIV.

    • Liver, renal or thyroid function tests.

    • Full blood count (to exclude anaemia, signs of infection).

    • Neurological examination.

Treatment of opioid intoxication1

  • If a patient has collapsed and is thought to be acutely intoxicated, call 999/112/911 and refer urgently to hospital.

  • Naloxone (a pure opioid antagonist used for reversing opioid intoxication) has a rapid onset of action and can be given intramuscularly, IV or subcutaneously.

  • Therapy is otherwise mostly supportive - eg, maintain airway, ventilation if necessary and IV fluids.

Treatment of opioid dependence1

A keyworker needs to work with the drug misuser to determine if they are suitable for substitute prescribing. The drug misuser also has to decide whether they would prefer opioid detoxification or induction and maintenance substitute prescribing. Detoxification from maintenance therapy at a later stage is an alternative.

Recovery orientation attempts to improve on the previously somewhat defeatist attitude that few patients are curable and that the best that can be achieved is that challenging behaviour, criminality and risks to public safety are reduced. This may mean accepting that a large proportion of patients would remain on lifelong opiate substitution therapy. The goal of the recovery-orientation approach is that services should be reorganised with the aim of making it possible for patients to look beyond detoxification to a point where they will not only be able to stop substitution therapy but aim to become fully functioning members of society.6

Opioid substitution with methadone or buprenorphine can be highly effective in reducing illicit opioid use and improving multiple health and social outcomes-eg, by reducing overall mortality and key causes of death, including overdose, suicide, HIV, hepatitis C virus, and other injuries.7

See separate Substitute Prescribing for Opioid Dependence article. Psychosocial components of treatment are also important and are outlined in the separate Drug Misuse and Dependence UK guidelines article.


  • Relapse rates are greater than 90% in untreated people.

  • The mortality risk of people dependent on illicit diamorphine is around 12 times that of the general population.

  • People with other coexisting conditions have a poorer prognosis, eg, mental health problems, cognitive impairment.

  • Of 121,332 people who exited the drug and alcohol treatment system in England in 2017–2018:

    • 48% successfully completed treatment and were free from dependence. However, people treated for opioid use had the lowest rate of successful exits at 26% compared to others taking non-opioids or alcohol.

    • 1.2% of people in the opioid group died in treatment. The median age of was 45, and 77% were male.

  • A large proportion of the opioid users in treatment have entrenched long-term drug use, are often in ill health and less likely to have access to the personal and social resources that can aid recovery, such as employment and stable housing. This often results in them being less likely to complete treatment successfully or sustain their recovery, when compared to people who use other drugs, or only alcohol.

  • In 2017 in England, the number of deaths from drug misuse decreased by 3.2% to 2310 — the first decrease since 2012 after increases of 3.7% between 2015 and 2016, 8.5% between 2014 and 2015 and 17% between 2013 and 2014.

  • A long-term follow-up study of 581 male opioid users in the US found that after 24 years, 29% were abstinent, 28% had died, 23% had positive urine tests for opioids, and 18% were in prison.

  • Between a quarter and a third of those entering drug treatment are able to achieve long-term abstinence.

Further reading and references

  1. Opioid dependence; NICE CKS, April 2022 (UK access only)
  2. Drug misuse in over 16s: opioid detoxification; NICE Clinical Guideline (July 2007)
  3. Naltrexone for the management of opioid dependence; NICE Technology Appraisal Guidance, January 2007
  4. International Classification of Diseases 11th Revision; World Health Organization, 2019/2021
  5. British National Formulary (BNF); NICE Evidence Services (UK access only)
  6. Strang J; Medications in Recovery Re-orientating Drug Dependence Treatment (archived content), National Treatment Agency for Substance Abuse, 2012
  7. Degenhardt L, Grebely J, Stone J, et al; Global patterns of opioid use and dependence: harms to populations, interventions, and future action. Lancet. 2019 Oct 26;394(10208):1560-1579. doi: 10.1016/S0140-6736(19)32229-9. Epub 2019 Oct 23.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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