Central nervous system drugs analgesics

Neuropathic pain is initiated or caused by a primary lesion in the peripheral or central nervous system. The causative agent may be trauma, nerve-invading cancer, herpes zoster, HIV, stroke, diabetes, alcohol or other toxic substances. Neuropathic pain is refractory to most analgesic drugs. Altered sodium channel activity is characteristics of neuropathic pain states. 

Analgesics are divided into two groups opioids (morphine-like substances), which predominantly influence the central nervous system (CNS) and nonopioids (nonsteroidal antiinflammatory or fever-reducing drugs—NSAID), which act predominantly on the peripheral nervous system. 

The principal xanthines of medical interest include caffeine, theophylline and aminophylline. Caffeine is synthesized by several plants and was originally isolated from tea in 1838. It is a methylxanthine (Figure 1.12) which stimulates the central nervous system, increasing mental alertness. It also acts as a diuretic and stimulates gastric acid secretion. It is absorbed upon oral administration and is frequently included in drugs containing an analgesic, such as aspirin or paracetamol. 

Janssen, P.A. and Van der Eycken, C.A. The chemical anatomy of potent morphine-like analgesics, in Drugs affecting the central nervous system, edited by A. Burger, 1968, 25-60, Marcel Decker, New York. 

Generally speaking, fentanyl acts on the central nervous system and the gastrointestinal tract. Because of this, most of the effects of the drug are physical. It also causes many of the same effects as heroin, including euphoria and drowsiness. However, some research shows that the effects of heroin are more euphoric, and fentanyl is more analgesic. 

Katzung PHARMACOLOGY, 9e > Section V. Drugs That Act in the Central Nervous System > Chapter 31. Opioid Analgesics Antagonists > ... 

Opioids are compounds that bind one or more of the many different opioid receptors in the body. Opioids act primarily on the central nervous system. The selectivity of a given opioid for the various opioid receptors determines its characteristic activity. While many opioids are powerful analgesics, opioids often cause physical dependence and have tolerance issues. Sedation and decreased rate of breathing are also side effects associated with opioids. Despite their problems, opioids are generally the drug of choice for treating severe, acute pain. 

Drugs and chemicals are known to cause activated interaction. The depressant action of opioid drugs is enhanced by drugs acting on the central nervous system (CNS) such as alcohol, anesthetics, anxiolytics, hypnotics, tricyclic antidepressants, and antipsychotics. Concomitant administration of opioid analgesics and monoamine oxidase inhibitors (MAOIs) should be avoided, or extra care should be taken if such a therapy is inevitable. Fatal reactions are reported when treated along with selegiline. Interactions also are reported with cyclizine, cimetidine, mexiletine, cisapride, metoclopramide, or domperidone. 

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