What are the common names of opioids of abuse and their typical routes of administration in a given region?

Common Opioids of Abuse and Their Routes of Administration

Most Commonly Abused Opioid Medications

The most frequently abused prescription opioids include oxycodone, hydrocodone, morphine, fentanyl, hydromorphone, and methadone, with oral intake remaining the predominant route of abuse despite common misconceptions about injection use. 1

Pure Opioid Agonists (Most Common)

• Morphine: Available in oral, parenteral (IV/subcutaneous), and rectal formulations; commonly abused through oral and injection routes 1
• Oxycodone: Available in immediate-release and extended-release oral formulations; oral route is most common for both therapeutic use and abuse 1, 2
• Hydrocodone: Typically combined with acetaminophen in oral formulations; oral route predominates 3, 4
• Fentanyl: Available as transdermal patches, transmucosal lozenges, buccal tablets, intranasal, and parenteral formulations; abused through multiple routes including oral, transdermal, intranasal, and injection 1, 5
• Hydromorphone: Available in oral and parenteral forms; abused through oral and injection routes 1
• Methadone: Long-acting oral formulation; primarily abused orally but associated with disproportionate overdose deaths 1

Weaker Opioid Agonists

• Codeine: Available in oral formulations, often combined with acetaminophen; oral route predominates 1
• Meperidine: Parenteral formulation; not recommended for chronic pain due to neurotoxicity risk from metabolite accumulation 1

Routes of Administration by Frequency

Primary Route: Oral (Most Common)

Oral intake is the most common route of opioid abuse, and abuse-deterrent formulations do not prevent this route of misuse. 1, 6

• Immediate-release tablets and capsules can be taken intact or crushed 1
• Extended-release formulations may be manipulated to defeat time-release mechanisms 1
• Liquid formulations (e.g., codeine-containing cough syrups) 1

Secondary Routes

• Intranasal (snorting): Crushed tablets insufflated; abuse-deterrent formulations may provide marginal benefit against this route 6
• Intravenous injection: Dissolved tablets or diverted parenteral formulations; associated with higher overdose risk 1
• Transdermal: Fentanyl patches may be applied inappropriately, cut, chewed, or the gel extracted for other routes 1, 5
• Smoking: Less common but reported with certain formulations 1

Critical Clinical Considerations

Overdose Risk by Formulation

Methadone and transdermal fentanyl carry particularly high overdose risk due to complex pharmacokinetics and delayed peak effects. 1

• Methadone has a long, variable half-life (8 to >120 hours) with peak respiratory depression occurring later than peak analgesia 1
• Transdermal fentanyl has gradually increasing serum concentrations over the first 24 hours, with variable absorption affected by external heat 1, 5
• Extended-release/long-acting (ER/LA) formulations should never be initiated in opioid-naïve patients 1

Geographic and Temporal Trends

From 1997 to 2007, retail sales increased dramatically: oxycodone by 866%, hydrocodone by 280%, fentanyl by 525%, and methadone by 1,293% 4. Despite increased medical use, the proportion of emergency department mentions for opioid abuse relative to total drug abuse decreased from 5.1% to 3.8% between 1990-1996, though absolute numbers increased 2.

Common Pitfalls to Avoid

• Do not assume abuse-deterrent formulations prevent misuse: These technologies do not prevent oral abuse (the most common route) or unintentional overdose 1, 6
• Do not underestimate oral route prevalence: Injection and intranasal routes receive disproportionate attention, but oral intake remains the primary abuse route 1
• Recognize delayed toxicity: Edible/oral routes may have delayed onset, leading users to repeat doses and causing delayed higher plasma concentrations 1
• Monitor for manipulation: Extended-release formulations may be crushed, chewed, or dissolved to defeat time-release properties 1

Substances to Avoid in Pain Management

Mixed agonist-antagonists (butorphanol, pentazocine), propoxyphene, and meperidine are not recommended for chronic pain management due to limited efficacy, neurotoxicity risk, and potential to precipitate withdrawal 1, 3.