While morphine is the commonest example used in medicine, many other opioid drugs are regularly prescribed as analgesics, including drugs like hydromorphone and oxycodone. The illegal drugs of heroin and carfentanil are opioids. The goal is the easy administration of a single dose of drug to bring about a peaceful and reliable death. Yet all opiates have properties that make them difficult drugs for a person to use to reliably end their life.
Fig 10.1: Greek god Morpheus, god of dreams, with Iris.
The Dual Problems of Sensitivity and Tolerance
The difficulties of using opioids to reliably end life are well can be demonstrated using morphine as an example.
The biggest problem associated with taking opioids is predicting the effect of a particular dose. There is remarkable individual variability in sensitivity to these drugs within the normal population. People who are similar physically (same height, weight, sex etc) can have a vastly different response to the administration of the same dose of a drug.
A small opioid dose may have almost no effect on one person, while that same dose could kill another person. Predicting the effect of the drug on an individual is difficult. When these drugs are used clinically, where accidental death would be disastrous, the rule of thumb has been to ‘start low and go slow’ until the individual’s sensitivity to the drug is established.