Английская Википедия:Analgesic

Материал из Онлайн справочника
Перейти к навигацииПерейти к поиску

Шаблон:Short description Шаблон:For Шаблон:Redirect Шаблон:Infobox drug class An analgesic drug, also called simply an analgesic, pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in some instances eliminate, sensation, although analgesia and anesthesia are neurophysiologically overlapping and thus various drugs have both analgesic and anesthetic effects.

Analgesic choice is also determined by the type of pain: For neuropathic pain, recent research has suggested that classes of drugs that are not normally considered analgesics, such as tricyclic antidepressants and anticonvulsants may be considered as an alternative. [1]

Various analgesics, such as many NSAIDs, are available over the counter in most countries, whereas various others are prescription drugs owing to the substantial risks and high chances of overdose, misuse, and addiction in the absence of medical supervision.

Etymology

The word analgesic derives from Greek an- (Шаблон:Lang, "without"), álgos (Шаблон:Lang, "pain"),[2] and -ikos (Шаблон:Lang, forming adjectives). Such drugs were usually known as "anodynes" before the 20th century.Шаблон:SfnpШаблон:Sfnp

Classification

Analgesics are typically classified based on their mechanism of action.[3]

Файл:Tylenol.jpg
A bottle of acetaminophen

Paracetamol (acetaminophen)

Шаблон:Main Paracetamol, also known as acetaminophen or APAP, is a medication used to treat pain and fever.[4] It is typically used for mild to moderate pain.[4] In combination with opioid pain medication, paracetamol is now used for more severe pain such as cancer pain and after surgery.[5] It is typically used either by mouth or rectally but is also available intravenously.[4][6] Effects last between two and four hours.[6] Paracetamol is classified as a mild analgesic.[6] Paracetamol is generally safe at recommended doses.[7]

NSAIDs

Шаблон:Main Nonsteroidal anti-inflammatory drugs (usually abbreviated to NSAIDs), are a drug class that groups together drugs that decrease pain[8] and lower fever, and, in higher doses, decrease inflammation.[9] The most prominent members of this group of drugs, aspirin, ibuprofen and naproxen, are all available over the counter in most countries.[10]

COX-2 inhibitors

Шаблон:Main

These drugs have been derived from NSAIDs. The cyclooxygenase enzyme inhibited by NSAIDs was discovered to have at least two different versions: COX1 and COX2. Research suggested most of the adverse effects of NSAIDs to be mediated by blocking the COX1 (constitutive) enzyme, with the analgesic effects being mediated by the COX2 (inducible) enzyme. Thus, the COX2 inhibitors were developed to inhibit only the COX2 enzyme (traditional NSAIDs block both versions in general). These drugs (such as rofecoxib, celecoxib, and etoricoxib) are equally effective analgesics when compared with NSAIDs, but cause less gastrointestinal hemorrhage in particular.[11]

After widespread adoption of the COX-2 inhibitors, it was discovered that most of the drugs in this class increase the risk of cardiovascular events by 40% on average. This led to the withdrawal of rofecoxib and valdecoxib, and warnings on others. Etoricoxib seems relatively safe, with the risk of thrombotic events similar to that of non-coxib NSAID diclofenac.[11]

Opioids

Шаблон:Main

Morphine, the archetypal opioid, and other opioids (e.g., codeine, oxycodone, hydrocodone, dihydromorphine, pethidine) all exert a similar influence on the cerebral opioid receptor system. Buprenorphine is a partial agonist of the μ-opioid receptor, and tramadol is a serotonin norepinephrine reuptake inhibitor (SNRI) with weak μ-opioid receptor agonist properties.[12] Tramadol is structurally closer to venlafaxine than to codeine and delivers analgesia by not only delivering "opioid-like" effects (through mild agonism of the mu receptor) but also by acting as a weak but fast-acting serotonin releasing agent and norepinephrine reuptake inhibitor.[13][14][15][16] Tapentadol, with some structural similarities to tramadol, presents what is believed to be a novel drug working through two (and possibly three) different modes of action in the fashion of both a traditional opioid and as an SNRI. The effects of serotonin and norepinephrine on pain, while not completely understood, have had causal links established and drugs in the SNRI class are commonly used in conjunction with opioids (especially tapentadol and tramadol) with greater success in pain relief.

Dosing of all opioids may be limited by opioid toxicity (confusion, respiratory depression, myoclonic jerks and pinpoint pupils), seizures (tramadol), but opioid-tolerant individuals usually have higher dose ceilings than patients without tolerance.[17] Opioids, while very effective analgesics, may have some unpleasant side-effects. Patients starting morphine may experience nausea and vomiting (generally relieved by a short course of antiemetics such as phenergan). Pruritus (itching) may require switching to a different opioid. Constipation occurs in almost all patients on opioids, and laxatives (lactulose, macrogol-containing or co-danthramer) are typically co-prescribed.[18]

When used appropriately, opioids and other central analgesics are safe and effective; however, risks such as addiction and the body's becoming used to the drug (tolerance) can occur. The effect of tolerance means that frequent use of the drug may result in its diminished effect. When safe to do so, the dosage may need to be increased to maintain effectiveness against tolerance, which may be of particular concern regarding patients with chronic pain and requiring an analgesic over long periods. Opioid tolerance is often addressed with opioid rotation therapy in which a patient is routinely switched between two or more non-cross-tolerant opioid medications in order to prevent exceeding safe dosages in the attempt to achieve an adequate analgesic effect.

Opioid tolerance should not be confused with opioid-induced hyperalgesia. The symptoms of these two conditions can appear very similar but the mechanism of action is different. Opioid-induced hyperalgesia is when exposure to opioids increases the sensation of pain (hyperalgesia) and can even make non-painful stimuli painful (allodynia).[19]

Alcohol

Шаблон:See also Alcohol has biological, mental, and social effects which influence the consequences of using alcohol for pain.[20] Moderate use of alcohol can lessen certain types of pain in certain circumstances.[20]

The majority of its analgesic effects come from antagonizing NMDA receptors, similarly to ketamine, thus decreasing the activity of the primary excitatory (signal boosting) neurotransmitter, glutamate. It also functions as an analgesic to a lesser degree by increasing the activity of the primary inhibitory (signal reducing) neurotransmitter, GABA.[21]

Attempting to use alcohol to treat pain has also been observed to lead to negative outcomes including excessive drinking and alcohol use disorder.[20]

Cannabis

Шаблон:Main Medical cannabis, or medical marijuana, refers to cannabis or its cannabinoids used to treat disease or improve symptoms.[22][23] There is evidence suggesting that cannabis can be used to treat chronic pain and muscle spasms, with some trials indicating improved relief of neuropathic pain over opioids.[24][25][26]

Combinations

Analgesics are frequently used in combination, such as the paracetamol and codeine preparations found in many non-prescription pain relievers. They can also be found in combination with vasoconstrictor drugs such as pseudoephedrine for sinus-related preparations, or with antihistamine drugs for people with allergies.

While the use of paracetamol, aspirin, ibuprofen, naproxen, and other NSAIDS concurrently with weak to mid-range opiates (up to about the hydrocodone level) has been said to show beneficial synergistic effects by combating pain at multiple sites of action,[27][28] several combination analgesic products have been shown to have few efficacy benefits when compared to similar doses of their individual components. Moreover, these combination analgesics can often result in significant adverse events, including accidental overdoses, most often due to confusion that arises from the multiple (and often non-acting) components of these combinations.[29]

Alternative medicine

There is some evidence that some treatments using alternative medicine can relieve some types of pain more effectively than placebo.[30] The available research concludes that more research would be necessary to better understand the use of alternative medicine.[30]

Other drugs

Nefopam—a monoamine reuptake inhibitor, and calcium and sodium channel modulator—is also approved for the treatment of moderate to severe pain in some countries.[31]

Flupirtine is a centrally acting K+ channel opener with weak NMDA antagonist properties.[32] It was used in Europe for moderate to strong pain, as well as its migraine-treating and muscle-relaxant properties. It has no significant anticholinergic properties, and is believed to be devoid of any activity on dopamine, serotonin, or histamine receptors. It is not addictive, and tolerance usually does not develop.[33] However, tolerance may develop in some cases.[34]

Ziconotide, a blocker of potent N‐type voltage‐gated calcium channels, is administered intrathecally for the relief of severe, usually cancer-related pain.[35]

Adjuvants

Шаблон:Main Certain drugs that have been introduced for uses other than analgesics are also used in pain management. Both first-generation (such as amitriptyline) and newer antidepressants (such as duloxetine) are used alongside NSAIDs and opioids for pain involving nerve damage and similar problems. Other agents directly potentiate the effects of analgesics, such as using hydroxyzine, promethazine, carisoprodol, or tripelennamine to increase the pain-killing ability of a given dose of opioid analgesic.

Adjuvant analgesics, also called atypical analgesics, include orphenadrine, mexiletine, pregabalin, gabapentin, cyclobenzaprine, hyoscine (scopolamine), and other drugs possessing anticonvulsant, anticholinergic, and/or antispasmodic properties, as well as many other drugs with CNS actions. These drugs are used along with analgesics to modulate and/or modify the action of opioids when used against pain, especially of neuropathic origin.

Dextromethorphan has been noted to slow the development of and reverse tolerance to opioids, as well as to exert additional analgesia by acting upon NMDA receptors, as does ketamine.[36] Some analgesics such as methadone and ketobemidone and perhaps piritramide have intrinsic NMDA action.[37]

High-alcohol liquor, two forms of which were found in the US Pharmacopoeia up until 1916 and in common use by physicians well into the 1930s, has been used in the past as an agent for dulling pain, due to the CNS depressant effects of ethyl alcohol, a notable example being the American Civil War.[38]Шаблон:Better source needed However, the ability of alcohol to relieve severe pain is likely inferior to many analgesics used today (e.g., morphine, codeine). As such, in general, the idea of alcohol for analgesia is considered a primitive practice in virtually all industrialized countries today.

The anticonvulsant carbamazepine is used to treat neuropathic pain. Similarly, the gabapentinoids gabapentin and pregabalin are prescribed for neuropathic pain, and phenibut is available without prescription. Gabapentinoids work as α2δ-subunit blockers of voltage-gated calcium channels, and tend to have other mechanisms of action as well. Gabapentinoids are all anticonvulsants, which are most commonly used for neuropathic pain, as their mechanism of action tends to inhibit pain sensation originating from the nervous system.[39]

Other uses

Topical analgesia is generally recommended to avoid systemic side-effects. Painful joints, for example, may be treated with an ibuprofen- or diclofenac-containing gel (The labeling for topical diclofenac has been updated to warn about drug-induced hepatotoxicity.[40]); capsaicin also is used topically. Lidocaine, an anesthetic, and steroids may be injected into joints for longer-term pain relief. Lidocaine is also used for painful mouth sores and to numb areas for dental work and minor medical procedures. In February 2007 the FDA notified consumers and healthcare professionals of the potential hazards of topical anesthetics entering the bloodstream when applied in large doses to the skin without medical supervision. These topical anesthetics contain anesthetic drugs such as lidocaine, tetracaine, benzocaine, and prilocaine in a cream, ointment, or gel.[41]

Uses

Topical nonsteroidal anti-inflammatory drugs provide pain relief in common conditions such as muscle sprains and overuse injuries. Since the side effects are also lesser, topical preparations could be preferred over oral medications in these conditions.[42]

List of drugs with comparison


Research

Some novel and investigational analgesics include subtype-selective voltage-gated sodium channel blockers such as funapide and raxatrigine, as well as multimodal agents such as ralfinamide.[127]

See also

References

Citations

Шаблон:Reflist

Sources

Шаблон:Refbegin

Шаблон:Refend

Шаблон:- Шаблон:Analgesics Шаблон:Pain Шаблон:Major Drug Groups

Шаблон:Authority control

  1. Шаблон:Cite journal
  2. Шаблон:Cite web
  3. Шаблон:Cite web
  4. 4,0 4,1 4,2 Шаблон:Cite web
  5. Шаблон:Cite book
  6. 6,0 6,1 6,2 Шаблон:Cite book
  7. Шаблон:Cite journal
  8. Шаблон:Cite journal
  9. Шаблон:Cite journal
  10. Шаблон:Cite journal
  11. 11,0 11,1 Шаблон:Cite journal
  12. Шаблон:Cite journal
  13. Шаблон:Cite journal
  14. Шаблон:Cite journal
  15. Шаблон:Cite journal
  16. Шаблон:Cite journal
  17. Шаблон:Cite web
  18. Oxford Textbook of Palliative Medicine, 3rd ed. (Doyle D, Hanks G, Cherney I and Calman K, eds. Oxford University Press, 2004).
  19. Шаблон:Cite journal
  20. 20,0 20,1 20,2 Шаблон:Cite journal
  21. Шаблон:Cite journal
  22. Шаблон:Cite journal
  23. Шаблон:Cite web
  24. Шаблон:Cite journal
  25. Шаблон:Cite journal
  26. Шаблон:Cite journal
  27. Шаблон:Cite journal
  28. Шаблон:Cite journal
  29. Шаблон:Cite journal
  30. 30,0 30,1 *Шаблон:Cite journal
  31. Шаблон:Cite journal
  32. Шаблон:Cite journal
  33. Шаблон:Cite journal
  34. Шаблон:Cite journal
  35. Шаблон:Cite journal
  36. Шаблон:Cite journal
  37. Шаблон:Cite journal
  38. Шаблон:Cite journal
  39. Шаблон:Cite book
  40. Voltaren Gel (diclofenac sodium topical gel) 1% – Hepatic Effects Labeling Changes Шаблон:Webarchive
  41. [1] Шаблон:Webarchive
  42. Шаблон:Cite journal
  43. 43,0 43,1 43,2 43,3 43,4 Шаблон:Cite web
  44. 44,0 44,1 44,2 44,3 Шаблон:Cite book
  45. 45,0 45,1 45,2 45,3 45,4 45,5 45,6 45,7 45,8 Шаблон:Cite book
  46. 46,0 46,1 46,2 Шаблон:Cite book
  47. Шаблон:Cite web
  48. Шаблон:Cite web
  49. Шаблон:Cite journal
  50. 50,0 50,1 Шаблон:Cite web
  51. Шаблон:Cite web
  52. Шаблон:Cite web
  53. 53,0 53,1 Шаблон:Cite book
  54. Шаблон:Cite journal
  55. Шаблон:Cite journal
  56. Шаблон:Cite journal
  57. Шаблон:Cite web
  58. Шаблон:Cite journal
  59. Шаблон:Cite journal
  60. Шаблон:Cite journal
  61. Шаблон:Cite journal
  62. Шаблон:Cite journal
  63. Шаблон:Cite web
  64. Шаблон:Cite journal
  65. Шаблон:Cite journal
  66. Шаблон:Cite journal
  67. Шаблон:Cite journal
  68. Шаблон:Cite journal
  69. Шаблон:Cite journal
  70. Шаблон:Cite journal
  71. Шаблон:Cite journal
  72. Шаблон:Cite journal
  73. Шаблон:Cite web
  74. Шаблон:Cite web
  75. Шаблон:Cite journal
  76. Шаблон:Cite web
  77. Шаблон:Cite journal
  78. Шаблон:Cite web
  79. Шаблон:Cite journal
  80. Шаблон:Cite web
  81. Шаблон:Cite web
  82. Шаблон:Cite journal
  83. Шаблон:Cite journal
  84. Шаблон:Cite journal
  85. Шаблон:Cite journal
  86. Шаблон:Cite journal
  87. Шаблон:Cite journal
  88. Шаблон:Cite journal
  89. Шаблон:Cite journal
  90. Шаблон:Cite journal
  91. Шаблон:Cite journal
  92. Шаблон:Cite web
  93. Шаблон:Cite journal
  94. Шаблон:Cite journal
  95. Шаблон:Cite journal
  96. Шаблон:Cite web
  97. Шаблон:Cite web
  98. Шаблон:Cite web
  99. Шаблон:Cite web
  100. Шаблон:Cite web
  101. Шаблон:Cite web
  102. Шаблон:Cite web
  103. 103,0 103,1 Шаблон:Cite journal
  104. Шаблон:Cite web
  105. Шаблон:Cite web
  106. Шаблон:Cite journal
  107. Шаблон:Cite journal
  108. Шаблон:Cite web
  109. Шаблон:Cite journal
  110. Шаблон:Cite web
  111. Шаблон:Cite journal
  112. Шаблон:Cite journal
  113. Шаблон:Cite journal
  114. Шаблон:Cite journal
  115. Шаблон:Cite web
  116. Шаблон:Cite journal
  117. Шаблон:Cite journal
  118. Шаблон:Cite web
  119. Шаблон:Cite web
  120. Шаблон:Cite journal
  121. Шаблон:Cite journal
  122. Шаблон:Cite web
  123. Шаблон:Cite journal
  124. Шаблон:Cite web
  125. Шаблон:Cite journal
  126. 126,0 126,1 Шаблон:Cite web
  127. Шаблон:Cite journal