General Principles The non-narcotic analgesics, aspirin and paracetamol remain the first line drugs of choice for relief of musculo-skeletal conditions, while the narcotic are much more specified for severe pain of visceral origin. Often in severe musculo-skeletal pain a combination of non-narcotic with one of the milder narcotic (codeine or dihydro-codeine) combination of peripheral and central action. Best results are then obtained by writing the two separately rather than in the expensive fixed combination preparations. Paracetamol remains the first choice with least side-effects in mild to moderate pain. Aspirin is more potent but produces more side-effects especially gastric irritation. There is rarely any justification for use of the expensive non-steroidal anti-inflammatory drugs (NSAIDs) in self limiting acute painful conditions. These are mainly used for rheumatic disease as a safer, longer acting alternative to aspirin. The narcotic analgesics are indicated for the severe pain of terminal malignant disease, skeletal fractures, labour, surgical pain and sometimes sickle cell crises. They produce tolerance and dependance with repeated use but this does not contra-indicate their use. Concurrent use of chlorproma-zine or prochlorperazine (stemetil) prevents nausea or vomiting. Dose Response It must be emphasized that there is a wide variation in response to analgesics, both for pharmacokinetic and psychological reasons. Thus paracetamol and aspirin may completely fail to reach effect-tive blood levels if taken after a meal. After surgery, it is particularly important to titrate the dose regimen of morphineor pethidine to the individual patient. Thus 50mg i.m. 6 hourly may be effective in a little old lady while a large male after major surgery may require 100mg 3 hourly. It is best to write a large loading dose, to reassess the patient on more than one occasion and to write a FLEXIBLE REGIMEN e.g. 75 - 100mg 3 - 6 hourly.
