Part 2: Opioids (Strong) — Morphine, Fentanyl, Pethidine, and Buprenorphine

Clinical Reference for Healthcare Professionals. Not intended as a guide for recreational use.

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1. Morphine Sulphate

Field	Detail
INN / Salt	Morphine Sulphate
Drug Class	Opioid Analgesic (Full Mu Agonist)
Schedule	Schedule X + NDPS Act
Indian Brands	Morcontin, MST Continus, Morphitab
Legitimate Uses	Severe acute pain (post-surgical), cancer pain, palliative care

Mechanism of Action

Morphine is the prototypical opioid. It binds directly and powerfully to mu-opioid receptors in the brain and spinal cord, producing profound analgesia, euphoria, sedation, and respiratory depression. It also triggers the release of dopamine in the nucleus accumbens (the brain’s “reward center”).

Why It Is Diverted

Morphine is the gold standard of opioid abuse. It produces intense, immediate euphoria (“rush”) when injected intravenously. Oral forms are sometimes crushed to defeat extended-release mechanisms. In India, it is tightly controlled under the NDPS Act, making diversion difficult but not impossible from hospital settings.

Side Effects & Dangers of Abuse

• Fatal Respiratory Depression: The primary cause of death in opioid overdose. The brainstem “forgets” to breathe.
• Extreme Physical Dependence: Withdrawal is agonizing (severe body aches, diarrhea, vomiting, insomnia, restless legs).
• Tolerance: Rapid escalation of dose is required.
• Miosis: Pinpoint pupils are a diagnostic sign of opioid use.

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2. Fentanyl Citrate

Field	Detail
INN / Salt	Fentanyl Citrate
Drug Class	Synthetic Opioid Analgesic (Full Mu Agonist)
Schedule	Schedule X + NDPS Act
Indian Brands	Durogesic (patch), Fentanyl Injection, Fentora
Legitimate Uses	Severe chronic pain (transdermal patches), anesthesia, breakthrough cancer pain

Mechanism of Action

Fentanyl is a synthetic opioid that is 50 to 100 times more potent than Morphine. It binds to mu-opioid receptors with extremely high affinity, producing rapid, intense analgesia and euphoria.

Why It Is Diverted

Fentanyl transdermal patches are the primary target. Abusers extract the gel from used patches and ingest, inject, or smoke the concentrated Fentanyl. This is extraordinarily dangerous because the margin between a “high” and a fatal overdose is microscopic. Illicitly manufactured Fentanyl is a growing global crisis, though India’s diversion is primarily from medical supply chains.

Side Effects & Dangers of Abuse

• Extreme Overdose Risk: The lethal dose is measured in micrograms (millionths of a gram). Even touching concentrated Fentanyl can be dangerous.
• Respiratory Arrest: Happens rapidly and without warning.
• Rigidity: “Wooden chest syndrome” — the muscles become so rigid the patient cannot breathe.

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3. Pethidine Hydrochloride (Meperidine)

Field	Detail
INN / Salt	Pethidine Hydrochloride
Drug Class	Synthetic Opioid Analgesic
Schedule	Schedule X + NDPS Act
Indian Brands	Pethidine Injection (generic)
Legitimate Uses	Labor pain, acute surgical pain (increasingly disfavored)

Mechanism of Action

Pethidine is a synthetic opioid that binds to mu-opioid receptors. It also has weak local anesthetic properties and anticholinergic effects. Its metabolite, norpethidine, is neurotoxic.

Why It Is Diverted

Historically one of the most abused opioids among healthcare professionals (doctors, nurses) who have direct access to hospital drug stores. Its availability in injectable form makes it a high-value target for diversion.

Side Effects & Dangers of Abuse

• Neurotoxicity: The metabolite norpethidine accumulates with repeated dosing and causes tremors, myoclonus (muscle jerking), and seizures.
• Serotonin Syndrome: When combined with MAOIs or SSRIs, it can cause fatal serotonin toxicity.

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4. Buprenorphine Hydrochloride

Field	Detail
INN / Salt	Buprenorphine Hydrochloride
Drug Class	Opioid Analgesic (Partial Mu Agonist)
Schedule	Schedule H1 + NDPS Act
Indian Brands	Buprigesic, Norphin, Addnok (sublingual for de-addiction)
Legitimate Uses	Moderate to severe pain, Opioid Substitution Therapy (OST) for heroin addiction

Mechanism of Action

Buprenorphine is a partial agonist at the mu-opioid receptor. It binds with very high affinity but produces a “ceiling effect” — after a certain dose, increasing the amount does not produce more euphoria or respiratory depression. This makes it safer than full agonists but still abusable.

Why It Is Diverted

The sublingual tablets (used for de-addiction therapy) are widely diverted and injected intravenously in India, particularly in North-East India and Punjab. Injecting sublingual buprenorphine produces a rapid opioid high while bypassing the “ceiling effect” designed for oral use.

Side Effects & Dangers of Abuse

• Precipitated Withdrawal: If taken by someone who is already dependent on a full agonist (like heroin), buprenorphine’s partial agonism can actually precipitate a severe, immediate withdrawal.
• Injection-Site Infections: IV abuse of sublingual tablets causes severe vein damage, abscesses, and endocarditis.

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Next: Part 3: Benzodiazepines — Alprazolam, Diazepam, Lorazepam, Clonazepam