The Clinical journal of pain
-
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.
-
Healing or successful intervention usually leads to the resolution of pain. However, in some patients biologic or psychologic symptoms associated with pain persist despite treatment or apparent healing. In cases in which the etiology is not known, persistent pain is categorized as a clinical syndrome known as "chronic pain." Organic, psychologic, and socioenvironmental factors contribute to the development of chronic pain. ⋯ Before successful management can begin, the major etiologic factors and sequelae of the chronic pain syndrome must be understood. Antidepressants, neuroleptics, anticonvulsants, nonsteroidal anti-inflammatory drugs, and hydroxyzine have been proven effective in the treatment of pain syndromes. The treatment of patients who present with chronic pain must be individualized based on a comprehensive understanding of the factors underlying the chronic pain syndrome of each patient.
-
Headache is the most common complaint encountered in clinical practice. Approximately 45 million people in the United States experience chronic headaches. The management of migraine headache involves both pharmacologic and nondrug therapy. ⋯ Prophylactic therapy is focused on reducing the frequency and severity of the attacks. beta-Adrenergic blocking agents, such as propranolol, remain the primary agents for many migraine patients, although other drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDs), including ketoprofen, or calcium-channel blocking agents, such as verapamil, may be beneficial for many patients. For cluster headache and its variants, methysergide and corticosteroids are usually the drugs of choice. Patients with chronic cluster headache may achieve good results from long-term treatment with other therapies, including lithium carbonate, verapamil, and ketoprofen.
-
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.