Drugs are developed to provide a cure to an illness or to give relief from symptoms. Human pharmaceuticals are never developed to end life. Yet some drugs do cause death, especially if they are administered in ways that were not intended. The usual misuse is to exceed the suggested dose: ‘the overdose’.
All drugs have side-effects (effects other than the purpose for which they are designed), and most side-effects are more pronounced when a drug is misused or taken in overdose. The most serious of ‘side-effects’ is death and drugs with this side effect are dangerous, unpopular and avoided if possible.
A drug that does cause death in overdose will always be unpopular and there will be a search to develop safer alternatives. So, while there are some drugs that do reliably cause death if misused, this number is small and decreasing as they are replaced with safer, modern alternatives.
For example, the barbiturate sleeping drugs, so popular in the 1950’s, have now been replaced by modern, safer, non-lethal alternatives. The lethal tri-cyclic antidepressants have almost disappeared, replaced by safer serotonin-uptake inhibitors like Prozac, and pain-relieving lethal drugs like propoxyphene have already been replaced in many countries. The number of drugs that are of practical assistance to a person seeking a peaceful death decreases each year.