ABSTRACT
Introduction 185 Opioid action 185 Development and opioid efficacy 186 Pharmacogenetics 188 Physiological effects of opioids 189
Spinal opioids 190 Opioids in clinical use 190 Opioid agonist-antagonists 193 Opioid antagonists 193 References 193
Preparations of the opium poppy Papaver somniferum have been used for hundreds of years, as sedatives and for the treatment of pain and diarrhoea. In the early nineteenth century Sertürner isolated a crystalline sample of the main constituent alkaloid and named it after Morpheus, the God of Dreams. Morphine was subsequently shown to be the main analgesic constituent of opium.
