Analgesia, Tolerance and Drug Dependence

Abstract

Pain is a peculiar function with many psychic, neural and endocrine aspects. It is the most common reason for patients to come to a doctor, and in spite of the rapidly expanding possibilities of causal therapy, symptomatic pain relief has still remained one of the main tasks of medical practice. In addition, as a result of rapid drug development, the majority of drugs prescribed, especially those for causal therapy, have been produced in the last two decades, while the analgetics most widely used like morphine, codeine, acetylsalicylic acid, aminopyrine, phen-acetin were all developed before this century. Unfortunately, these analgetics do not owe their steady use to some ideal properties but to the mere fact that none of the many products of a world-wide intensive research has met better the requirements of the “ideal agent”. An ideal agent would be effective against either mild or severe pain, it would be free from respiratory depressant and other side effects and it would be non-addicting. Of the drugs used neither the so-called “major” nor the “minor” analgetics fulfil these criteria. The minor, or antipyretic analgetics are effective only against mild pain and evoke serious side effects. Because of the danger of bone-marrow depression and agranulocytosis aminopyrine is not used anymore in many countries. There is a world-wide tendency to withdraw phenacetin, too, since it damages haemoglobin in the circulating erythrocytes.