Psychiatry
Substance Use Disorders
Substance use disorders for MBBS and NEET-PG: dependence, alcohol withdrawal and delirium tremens, Wernicke-Korsakoff, opioid overdose and naloxone, mapped to NMC codes PS4.
MedNext Academy | 3 min read
Substance Use Disorders
Substance use disorders for MBBS and NEET-PG: dependence, alcohol withdrawal and delirium tremens, Wernicke-Korsakoff, opioid overdose and naloxone, mapped to NMC codes PS4.
This chapter covers the disorders arising from alcohol, opioids, tobacco and other drugs. It sets out the concept of dependence, the recognition and treatment of intoxication and withdrawal states, the medical complications, and the pharmacological and psychosocial management of substance use disorders.
High-yield: Substance Use Disorders
- Dependence is defined by tolerance, withdrawal, craving, loss of control and continued use despite harm.
- Alcohol is a central nervous system depressant, and its withdrawal is potentially fatal, unlike opioid withdrawal which is distressing but rarely fatal.
- Delirium tremens appears two to four days after the last drink with confusion, tremor, autonomic overactivity and visual hallucinations, and is a medical emergency.
- Benzodiazepines such as chlordiazepoxide are the first-line treatment for alcohol withdrawal and prevent seizures and delirium tremens.
- Thiamine must be given before glucose in a malnourished drinker to prevent Wernicke encephalopathy.
- Wernicke encephalopathy is the triad of confusion, ophthalmoplegia and ataxia, and untreated it progresses to the irreversible amnesia of Korsakoff psychosis.
- Disulfiram deters drinking by causing an unpleasant reaction with alcohol, while naltrexone and acamprosate reduce craving and relapse.
- Opioid overdose causes pinpoint pupils, respiratory depression and coma, and is reversed with naloxone.
- Opioid dependence is managed with substitution using methadone or buprenorphine alongside psychosocial support.
- The CAGE questionnaire is a quick screen for problem drinking.
- Wernicke-Korsakoff, cirrhosis, pancreatitis and cardiomyopathy are important complications of chronic alcohol use.
- Nicotine dependence is treated with behavioural support plus nicotine replacement, bupropion or varenicline.
- Motivational interviewing helps move a person towards a decision to change substance use.
- Relapse prevention combines medication, counselling and community support, as substance use disorders are chronic and relapsing.
Withdrawal and its management
- **Alcohol withdrawal:** Tremor, seizures, delirium tremens. Treat with benzodiazepines and thiamine.
- **Opioid overdose:** Pinpoint pupils, respiratory depression. Reverse with naloxone.
- **Deterrent and anti-craving:** Disulfiram deters drinking; naltrexone and acamprosate reduce craving.
- **Opioid substitution:** Methadone or buprenorphine with psychosocial support.
NMC competencies in this chapter
- **PS4.1:** Magnitude and aetiology of alcohol and substance use disorders
- **PS4.2:** Clinical features of alcohol and substance use disorders
- **PS4.3:** Treatment of alcohol and substance use disorders
- **PS4.4:** Family education in substance use disorders
- **PS4.5:** Pharmacological basis and side effects of therapies
- **PS4.6:** Conditions for specialist referral
- **PS4.7:** Prevention and rehabilitation in substance use
Frequently Asked Questions
Why is thiamine given before glucose in an alcoholic?
Giving glucose first in a thiamine-deficient drinker can precipitate Wernicke encephalopathy, so thiamine is administered before or with glucose to protect the brain.
What is delirium tremens?
It is a severe alcohol withdrawal state appearing two to four days after the last drink, with confusion, tremor, autonomic overactivity and visual hallucinations. It is a medical emergency managed with benzodiazepines.
How is opioid overdose treated?
Opioid overdose causes pinpoint pupils, respiratory depression and coma, and is reversed with naloxone alongside airway and breathing support.
Which drugs help maintain abstinence from alcohol?
Disulfiram deters drinking by causing an unpleasant reaction with alcohol, while naltrexone and acamprosate reduce craving and lower the risk of relapse.
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