Opioids classification

Based on source

1) Natural Opium Alkaloids

a) Phenanthrenes

Morphine

Codeine

Thebaine

b) Benzoisoquinolines (non analgesic)

Papaverine

Noscapine

2) Semisynthetic opiates

Diacetylmorphine

Ethylmorphine

Pholcodeine

3) Synthetic opioids

Pethidine

Methadone

Fentanyl

Tramadol

Levorphanol

Ethoheptazine

Dextropropoxyphene

Based on mode of action

1) Pure Agonists

Morphine

Fentanyl

2) Partial μ Agonists

Buprenorphine

Propiram

3) Agonist- Antagonists

Butorphanol

Pentazocine

Nalbuphine

Nalorphine

4) Pure competitive Antagonists

Naloxone

Naltrexone 

Nalmefene