# Opioid Use Disorder

> Opioid use disorder notes for NEET-PG Psychiatry covering intoxication, withdrawal timeline, methadone, buprenorphine, naltrexone and naloxone overdose care.

- Canonical URL: https://prepelephant.com/topics/neet-pg/psychiatry/opioid-use-disorder
- Exam / course: NEET-PG · Subject: Psychiatry
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Opioid Use Disorder", PrepElephant, https://prepelephant.com/topics/neet-pg/psychiatry/opioid-use-disorder

## Direct answer

Opioid use disorder is a pattern of opioid use (heroin, pharmaceutical opioids, or in the Indian context commonly injected or misused prescription preparations such as dextropropoxyphene, tramadol and pentazocine-containing products) leading to impairment, tolerance and withdrawal. Intoxication produces euphoria, analgesia, sedation, pinpoint pupils and constipation; overdose causes coma, respiratory depression and death, reversed urgently by the antagonist naloxone. Withdrawal — lacrimation, rhinorrhoea, sweating, piloerection, mydriasis, diarrhoea, muscle aches and intense craving — is severe but rarely life-threatening, and treatment follows substitution with methadone or buprenorphine, gradual detoxification, antagonist maintenance with naltrexone and psychosocial rehabilitation.

## What you must remember

- **Intoxication triad:** pinpoint pupils, respiratory depression and depressed consciousness; the antidote is naloxone, repeated as needed because its half-life is shorter than most opioids.
- **Withdrawal timeline:** begins 6-24 hours after the last short-acting opioid (peaking 36-72 hours, settling in 5-7 days) with "cold turkey" features — lacrimation, rhinorrhoea, yawning, piloerection, myalgia, cramps, diarrhoea and craving; longer for methadone.
- **Withdrawal scoring:** the Clinical Opioid Withdrawal Scale guides substitution dosing; clonidine dampens noradrenergic symptoms but substitution is more effective.
- **Agonist maintenance:** methadone (full mu agonist) or buprenorphine (partial agonist, safer in overdose) — the backbone of deaddiction; buprenorphine is widely used in India, methadone in designated centres.
- **Detoxification:** gradual tapering over days to weeks with symptomatic cover (clonidine, NSAIDs, loperamide); rapid antagonist-accelerated protocols under anaesthetic cover for selected cases.
- **Relapse prevention:** oral naltrexone only after full detoxification, take-home naloxone for overdose safety per current guidance, plus psychosocial intervention and self-help groups.
- **Complications:** injecting use carries HIV, hepatitis, endocarditis and abscesses; neonatal abstinence syndrome in exposed infants.

## Common confusion

Opioid withdrawal versus sedative or alcohol withdrawal is a life-or-death distinction: opioid withdrawal is miserable but not lethal, whereas abrupt alcohol or benzodiazepine withdrawal can cause seizures and death — so a shaky, sweating patient with dilated pupils and diarrhoea gets opioid detoxification, while one with tremor, disorientation and a history of drinking gets benzodiazepines. Buprenorphine versus methadone is also tested: buprenorphine is a partial agonist with a ceiling on respiratory depression, and precipitated withdrawal occurs if it is started too early after a full agonist. Pentazocine and tramadol produce both opioid and atypical withdrawal features worth remembering.

## Exam-focused takeaway

NEET-PG vignettes show a young injected-drug user with pinpoint pupils and drowsiness (naloxone answer), or 24 hours after last heroin with yawning, gooseflesh and diarrhoea (buprenorphine-methadone detoxification answer). One-liners test miosis in intoxication versus mydriasis in withdrawal, naloxone as the overdose antidote, the partial-agonist status of buprenorphine, and naltrexone for antagonist maintenance after detoxification. Expect an HIV-screening or needle-exchange angle reflecting Indian national programme teaching.

## Frequently asked questions

### What are the features of acute opioid intoxication?

Sedation, miosis, respiratory depression and constipation; overdose progresses to coma and apnoea.

### Which drug reverses opioid overdose?

Naloxone, repeated as needed because many opioids outlast its effect.

### What characterises opioid withdrawal?

Lacrimation, rhinorrhoea, yawning, piloerection, mydriasis, cramps, diarrhoea and craving — severe but not life-threatening.

### Why is buprenorphine preferred in many deaddiction programmes?

Partial agonism with a ceiling on respiratory depression allows safe sublingual maintenance.

### When is naltrexone used in opioid dependence?

Only after complete detoxification, as antagonist maintenance for motivated patients.

### What is the role of clonidine in opioid withdrawal?

It suppresses noradrenergic symptoms such as sweating and restlessness but not craving.