The Clinical journal of pain
-
This article reviews the literature and describes clinical methods of providing analgesia for acute pain using epidural and intrathecal (spinal) opiates. The mechanism of action of these drugs, their basic pharmacology and spinal pharmacodynamics, and useful drugs and dosages are presented. The side effects of these drugs when administered by injection and possible ways to diminish their incidence and severity are discussed. A clinical protocol for the dosage and selection of these drugs is included.
-
Recent research advances indicate that specialized neural pathways are involved in the encoding of pain sensations and that these pathways are sensitive to changes in stimulus features, such as intensity, quality, duration, and location. It has also been established that there are three major families of opioid peptides in the brain: the enkephalins, the dynorphins, and the endorphins. In addition to these opioid peptides, other neurochemicals such as serotonin and norepinephrine play a role in the modulation of signals related to tissue damage. ⋯ Opioid drugs are administered into the membranes surrounding the spinal cord to provide long-lasting pain relief. Peripherally acting opioid drugs may represent a new functional class of analgesics devoid of the undesirable side effects of centrally acting opioids. Tricyclic antidepressant drugs are used in the treatment of neuropathic pain, based on their effects on noradrenergic and serotoninergic pathways in the central nervous system.
-
Migraine headache variants consist of the complicated migraine headache subtypes such as basilar artery migraine, migraine equivalents, and late-life migraine accompanients. Although these disorders occur infrequently, diagnosis may be more difficult. Generally, comprehensive diagnostic studies are required to rule out underlying pathogenic conditions that may present with similar symptom complexes. Standard migraine treatment is often useful in these disorders; however, migrainous variants deserve special therapeutic considerations.
-
Opioid receptors are described and differentiated by their affinities for specific agonists and antagonists. Their sites of action and receptor activities are discussed. Tachyphylaxis and tolerance are described and methods for overcoming these problems are recommended. Suggestions are made regarding future drugs to act at specific receptors.