What are Analgesics and its Classification? NCERT Chemistry Class 12

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Analgesics and its Classification NCERT Chemistry
Class 12
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Analgesics and its Classification NCERT Chemistry
Class 12

• What is Analgesics?
• Analgesics (known as painkillers) are a class of
  drugs that are generally used to reduce or
  relieve pain. It also remedies any displeasing
  emotional and sensory experience in a human body
  which is caused due to tissue damage or expressed
  in terms of such damage. The term Analgesic is
  derived from two Greek wordsan means without
  and algos means pain. So, analgesics are
  therapeutic substances that diminish or reduce
  pain.
• MODE OF ACTION
• When part of the body is injured or suffering
  from pain, special nerve endings send pain
  messages back to the brain. Painkilling drugs
  interfere with these messages, either at the site
  of the injury, in the spinal cord or in the brain
  itself. Many painkillers are based on one of two
  naturally occurring drugs aspirin and opiates. 

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Analgesics and its Classification NCERT Chemistry
Class 12

•  Aspirin ,also known as acetylsalicylic acid
  (ASA) is a mild analgesic and work by indirectly
  blocking the enzyme-controlled synthesis
  of Prostaglandins(Prostaglandins are hormone-like
  substances that participate in a wide range of
  body functions such as the contraction and
  relaxation of smooth muscle, the dilation and
  constriction of blood vessels, control of blood
  pressure, and modulation of inflammation). By
  restricting the synthesis of Prostaglandins, mild
  analgesics can reduce pain, fever, and
  inflammation. Chemical painkillers such
  as Endorphins and Enkephalins are produced
  naturally in the body. Aspirin uses a chemical
  found in willow bark, used by the Ancient Greeks
  to relieve pain. Opiates (any drug derived from
  opium), all work in a similar way to opium, which
  is extracted from poppies.
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Analgesics and its Classification NCERT Chemistry
Class 12

• CLASSIFICATION OF ANALGESICS
• Paracetamol (Acetaminophen)
• Paracetamol, also known as acetaminophen or APAP,
  is used to treat pain and fever. It is typically
  used for mild to moderate pain. In combination
  with opioid pain medication, paracetamol is now
  used for more severe pain such as cancer pain and
  after surgery. It is used either by mouth or
  rectally. It is also available intravenously. The
  effects last for two and four hours. Paracetamol
  is a mild analgesic. Paracetamol is a safe
  analgesic at recommended doses by the doctor.
• NSAIDs
• Nonsteroidal anti-inflammatory drugs (usually
  abbreviated to NSAIDs), are drugs that decrease
  pain and lower fever. In higher doses, it
  decreases inflammation also. The most prominent
  members of this group of drugs are aspirin,
  ibuprofen, and naproxen.

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Analgesics and its Classification NCERT Chemistry
Class 12

• COX-2 inhibitors
• These drugs have been derived from NSAIDs.
  The cyclooxygenase enzyme inhibited by NSAIDs has
  two forms COX1 and COX2. The analgesic effects
  are mediated by the COX2 (inducible)
  enzyme. Cyclooxygenase-2 (COX2), the enzyme acts
  to speed up the production of certain chemical
  messengers, called prostaglandins that play a key
  role in promoting inflammation. When COX-2
  activity is blocked, inflammation is reduced.
  Thus, the COX2 inhibitors were developed to
  inhibit only the COX2 enzyme. These drugs (such
  as rofecoxib, celecoxib, and etoricoxib) are
  equally effective analgesics when compared with
  NSAIDs, and cause less gastrointestinal
  haemorrhage.
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Analgesics and its Classification NCERT Chemistry
Class 12

• Opioids
• Morphine is an exemplary opioid. The other
  opioids are codeine, oxycodone, hydrocodone,
  dihydromorphine, pethidine) all exert a similar
  influence on the cerebral opioid receptor system.
  Certain side effects of opioids toxicity are
  confusion, respiratory depression, myoclonic
  jerks and pinpoint pupils, seizures (tramadol),
  but opioid-tolerant individuals usually have
  higher dose limits than patients without
  tolerance. Patients starting morphine may
  experience nausea and vomiting. Constipation
  occurs in almost all patients on opioids, and
  laxatives (lactulose, macrogol-containing or
  co-danthramer) are typically co-prescribed.
• Alcohol
• Alcohol has biological, mental, and social
  effects which influence the consequences.
  Moderate use of alcohol can lessen certain types
  of pain in certain circumstances. Use alcohol to
  treat pain, again and again, has also been
  observed to lead to negative outcomes including
  excessive drinking and alcohol use disorder.
• Medical cannabis

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Analgesics and its Classification NCERT Chemistry
Class 12

• Cannabis can be evidently used to treat chronic
  pain and muscle spasms. Trials are being done,
  indicating improved relief of neuropathic pain
  over opioids.
• Combinations
• Analgesic combination products contain either one
  or more types of analgesics with other medicines.
  The different analgesics generally have different
  modes of action and work simultaneously to reduce
  pain.
• The use of paracetamol, aspirin, ibuprofen,
  naproxen, and other NSAIDs along with weak to
  mid-range opiates (up to about the hydrocodone
  level) has shown beneficial synergistic effects
  by combatting pain at multiple sites of action.
  These combination analgesics can be used in
  significant adverse events, including accidental
  overdoses, especially due to the confusion that
  arises from the multiple (and often non-acting)
  components of these combinations.

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Analgesics and its Classification NCERT Chemistry
Class 12

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