Opioid analgesics : treatment

For the treatment of severe pain, reduce its sensory and emotional components are the major opioid analgesics. Opioids may be administered in traumatic and postoperative pain, chronic cancer pain and, in certain circumstances, for the treatment of severe chronic non-cancer pain.
Opioid analgesics interact with one or more subtypes of opioid receptors, ie m, d and k, at supraspinal, spinal and peripheral levels, causing analgesia, and many other effects. Opioids act by presynaptic inhibition of production of neurotransmitters C-fiber endings, postsynaptic suppression of evoked activity in nociceptive path or remove the remaining parts of the regulation of inhibition of nociceptive impulses. Supraspinal action of opioids is characterized by a strengthening of the descending inhibition of spinal transmission of nociceptive conduction. Opioid analgesics can be full agonists of specific opioid receptors, namely the m-receptor mixed agonist-antagonists have opposite effects on certain receptor subtype or partial m-agonist. Opioids are capable of causing physical and psychological dependence, and are the subject of illegal trade. They are therefore subject to control, assuming the legal responsibility of doctors and pharmacists. Safe use requires knowledge of available drugs, appropriate indications for use, dosage forms and routes of administration, as well as possible side effects and methods of prevention and treatment.
Opioid analgesic used for treatment of chronic pain should be well tolerated, does not cause severe sedation and suppress vital functions, allow the combined treatment and is slowly excreted from the body. The important point is the systematic use of opioids with the purpose of achieving the most effective drug concentration in the blood. Of great importance is compliance with a clear time schedule of drug administration (in hours). Opioids to treat chronic pain is not desirable to appoint injections. If the patient is not vomiting, the effectiveness of analgesics for oral administration is not following injection. Injection not only complicate the overall supervision, but also reinforce the "sick role", adding to the possibility of manipulation in relationships.