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ANALGESICS

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Suyog Mali
Suyog Mali

Analgesics are drugs that relieve pain by acting in the central nervous system or on peripheral pain mechanisms without altering consciousness. There are two main classes of analgesics: nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin, ibuprofen, and naproxen; and opioids like morphine, codeine, and fentanyl. NSAIDs work by blocking the enzyme cyclooxygenase, which produces inflammatory mediators. Opioids act on opioid receptors in the brain and spinal cord. Both classes have a long history of medical use and come with risks like gastrointestinal irritation, dependence, and respiratory depression that require precautions. The document provides details on the mechanisms, pharmacokinetics,

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Analgesics -SUYOG MALI III B.D.S
What is Analgesia? The word analgesia is derived from Greek word analgetos (an – without ; algesia – pain ) Analgesia simply means the absence of pain without losing consciousness’
Analgesics “Analgesics are drugs that selectively relieve pain by acting in the CNS or on the peripheral pain mechanisms, without altering consciousness” -
History of AnalgesicsHistory of Analgesics • BC:BC: Ancient Greeks and Romans used salicylate extracts derived from willow leaves as analgesics and antipyretics • Middle Ages: Medicinal herb gardens featured salicylate containing wintergreen and meadowsweet plants • 1763: Edward Stone reported on use of willow bark powder as an anti-inflammatory agent. • 1853: Von Gerhardt synthesized a crude form of aspirin (acetylsalicylic acid) • 1860: Felix Hoffman synthesized pure aspirin
continued • Opiates are one of the oldest types of drugs in history • Opium is extracted from poppy seeds (Paper somniforum) • Undisputed reference to opium found in writings from the third century BC • Use of Opium was first recorded in China over 2000 years ago • Greeks dedicated the Opium poppy to the Gods of Death (Thanatos), Sleep (Hypnos), and Dreams (Morpheus) • Sixteenth Century is the first reported use of Opium for its Analgesic qualities
Contnd… • 1949: The NSAID Phenylbutazone was introduced • 1963: Indomethacin was introduced • 1971: Vane and Piper demonstrated that NSAIDs inhibit prostaglandin production • 1974: Ibuprofen was introduced • 1976: Miyamoto et al identified the COX-1 enzyme • 1989: Simmons et al identified the COX-2 enzyme • 1999: The COXIBs celecoxib and rofecoxib were introduced • 2004: Rofecoxib was banned in india due to its cardiotoxic effect .
Important medicines include ibuprofen (Motrin), naproxen (Aleve) and Aspirin.  Can reduce fever and suppress inflammation.  Work by blocking cyclooxygenase (COX), an enzyme in various tissues that produce the chemical mediators which are the cause for inflammation, related pain, and fever.  Aspirin besides acting as a pain killer also has anti-platelet properties, which helps in the treatment for heart attacks and strokes.
Classification of NSAIDs • Non selective COX inhibitors (conventional NSAID’s) • Salicylates: Asprin • Propionic acid derivatives: Ibuprofen, Naproxen, Ketoprofen, Flurbiprofen • Anthranilic acid derivative: Mephenamic acid • Aryl-acetic acid derivatives: Diclofenac • Oxicam derivatives: Piroxicam, Tenoxicam • Pyrrolo-pyrrole derivative: Ketorolac • Indole derivative: Indomethacin • Pyrazolone derivatives: Phenylbutazone, Oxyphenbutazone
Classification of NSAID’s contd… • Preferential COX-2 inhibitors • Nimesulide, Meloxicam, Nabumetone • Selective COX-2 inhibitors • Celecoxib, Rofecoxib, Valdecoxib, Etoricoxib • Analgesics-antipyretics with poor anti inflammatory action • Para aminophenol derivative: Parcetamol (Acetaminophen) • Pyrazolone derivatives: Metamizol (Dipyrone), Propiphenazone • Benzoxazocine derivative: Nefopam
MECHANISM OF ACTION
Salicylates -Asprin • Is acetylsalicylic acid • Pharmacological actions • Analgesic, antipyretic, anti inflammatory actions • Analgesic action is due to prevention of PG mediated sensitization of nerve endings • Resets the hypothalamic thermoregulatory centre • Anti inflammatory at high doses • Blood • Long term use of large doses decreases synthesis of clotting factors in liver
Aspirin • Respiration • Anti inflammatory doses – stimulates respiration • Hyperventilation in salicylate poisoning, in doses higher than this there is respiratory depression • Acid-base electrolyte balance • Adults treated with aspirin 4-6g/day stay in a state of compensated respiratory alkalosis • Still higher doses can cause respiratory acidosis • Dehydration occurs in poisoning due to increased urine output, sweating and hyperventilation • CVS • No direct effect in therapeutic doses
Aspirin • GIT • Aspirin irritates gastric mucosa & causes epigastric pain, nausea and vomiting • ‘Acute ulcers, erosive gastritis, congestion and microscopic hemorrhages • Metabolic effects • Chronic use can cause negative nitrogen balance by increased conversion of protein to carbohydrate.
Aspirin • Pharmacokinetics • Absorbed from stomach and small intestine • Precautions and contraindications • Contraindicated in patients sensitive to it and in peptic ulcer, bleeding tendencies. • In chronic liver disease • Asprin should be stopped 5 days before elective surgery, dental extraction • Pregnancy and lactating mothers
Asprin • Adverse effects • Most important – gastric mucosal damage and peptic ulceration • Acute salicylate poisoning • Uses • As analgesic • As antipyretic • Acute rheumatic fever • Rheumatoid arthritis • Osteoarthritis
Propionic acid derivatives • Pharmacokinetics • Well absorbed orally • Uses • Analgesic and Antipyretic and anti-inflammatory • Soft tissue injuries, tooth extraction, fractures, post operative pain. • Rheumatoid arthritis, osteoarthritis and musculoskeletal disorders… where pain is more prominent than inflammation
Anthranilic acid dervative • Mephenamic acid- • Inhibits COX & antagonises certain actions of PG’s • Exerts peripheral as well as central analgesic action • Pharmacokinetics • Oral absorption is slow but complete • Adverse effects - Diarrhoea • Uses • Muscle, joint and soft tissue pain • Effective in dysmenorrhoea
Beneficial actions due to PGBeneficial actions due to PG synthesis inhibitionsynthesis inhibition • Analgesia • Anti pyresis • Anti inflammatory • Anti thrombotic
Routes of analgesic administration • Oral • Intramuscular Injection • Intravenous Injection • Other routes • Transdermal • Fentanyl patch • Sublingual • Morphine
Opioid analgesics
Classification of opioids • Natural opium alkaloids • Morphine, codeine • Semi synthetic opiates • Diacetylmorphine (heroin), pholcodeine • Synthetic opioids • Pethidine (meperidine), fentanyl, methadone, dextropropoxyphene, tramadol
Morphine • Alkaloid of opium • Widely used • Pharmacological actions • CNS • Analgesia • Strong analgesic • Nociceptive pain arising from peripheral pain receptors is better relieved than neuritic pain • Reactions associated with intense pain – apprehension, fear are also depressed
Morphine • CNS • Sedation • Drowsiness and indifference to surroundings as well as to own body , ataxia and apparent excitement also occur • Higher doses produce sleep and coma • Mood and subjective changes • Calming effect • Loss of apprehension, feeling of detachment,mental clouding and inability to concentrate
Morphine • Respiratory and cough centres • Depresses Repiration and Cough centre • Temperature regulating and vasomotor centre • Depressed • CTZ(chemoreceptor trigger zone), vagal centre & certain cortical areas are stimulated • GIT • Constipation is a prominent feature
Morphine • Neuro-endocrine • Enhances ADH release and so urine volume is reduced • Causes sympathetic stimulation – mild hypoglycemia • CVS • Causes vasodilation • Cardiac work is consistently reduced due to decrease in peripheral resistance
Morphine • Pharmacokinetics • Oral absorption is unreliable – high and variable first pass metabolism • Freely crosses placenta, affects foetus more than the mother • Adverse effects • Mental clouding, sedation and lethargy • constipation • Acute morphine poisoning • Human lethal dose is 250mg . • Death is due to respiratory failure
Morphine • Tolerance and dependence • Partly pharmacokinetic (enhanced rate of metabolism) but mainly pharmacodynamic (cellular tolerance) • Treated by substitution with oral methadone Precautions and contraindications • Infants and elderly • Bronchial asthma(wheezing) • Head injury •
Codeine • Is methyl morphine • Less potent than morphine (1/10th as analgesic) • Is more selective cough suppressant
Pethidine • Synthesized as an atropine substitute • Interacts with opioid receptors (mu) • Similar to morphine in most of its properties • Uses • As analgesic (substitute to morphine) • In pre anaesthetic medication
Methadone • Chemically dissimilar but pharmacologically similar to morphine • Used • primarily as substitution therapy for opioid dependence • Also in methadone maintenance therapy
Opioids in dental pain • Opioids are less effective and suitable than NSAID’s for dental pain • Mostly used as additional drugs with NSAID’s to boost their analgesic effect • Among opioids oral codeine is most suitable • Oral tramadol and pentazocine are alternatives
Analgesics & Medical conditions • NSAIDs should be given in 2nd triemister of pregnancy and opioids should be avoided . • Paracetamol is the safest drug to use in pregnancy • Aspirin & Ibuprofen should not be given in asthmatic patients • Aspirin & Paracetamol should not be given in nephropathy(affected state of kidney) • Codein should not be used in renal dysfunction while fentanyl & methadone are safe .
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
ANALGESICS
THANKY OU

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ANALGESICS

  • 2. What is Analgesia? The word analgesia is derived from Greek word analgetos (an – without ; algesia – pain ) Analgesia simply means the absence of pain without losing consciousness’
  • 3. Analgesics “Analgesics are drugs that selectively relieve pain by acting in the CNS or on the peripheral pain mechanisms, without altering consciousness” -
  • 4. History of AnalgesicsHistory of Analgesics • BC:BC: Ancient Greeks and Romans used salicylate extracts derived from willow leaves as analgesics and antipyretics • Middle Ages: Medicinal herb gardens featured salicylate containing wintergreen and meadowsweet plants • 1763: Edward Stone reported on use of willow bark powder as an anti-inflammatory agent. • 1853: Von Gerhardt synthesized a crude form of aspirin (acetylsalicylic acid) • 1860: Felix Hoffman synthesized pure aspirin
  • 5. continued • Opiates are one of the oldest types of drugs in history • Opium is extracted from poppy seeds (Paper somniforum) • Undisputed reference to opium found in writings from the third century BC • Use of Opium was first recorded in China over 2000 years ago • Greeks dedicated the Opium poppy to the Gods of Death (Thanatos), Sleep (Hypnos), and Dreams (Morpheus) • Sixteenth Century is the first reported use of Opium for its Analgesic qualities
  • 6. Contnd… • 1949: The NSAID Phenylbutazone was introduced • 1963: Indomethacin was introduced • 1971: Vane and Piper demonstrated that NSAIDs inhibit prostaglandin production • 1974: Ibuprofen was introduced • 1976: Miyamoto et al identified the COX-1 enzyme • 1989: Simmons et al identified the COX-2 enzyme • 1999: The COXIBs celecoxib and rofecoxib were introduced • 2004: Rofecoxib was banned in india due to its cardiotoxic effect .
  • 7. Important medicines include ibuprofen (Motrin), naproxen (Aleve) and Aspirin.  Can reduce fever and suppress inflammation.  Work by blocking cyclooxygenase (COX), an enzyme in various tissues that produce the chemical mediators which are the cause for inflammation, related pain, and fever.  Aspirin besides acting as a pain killer also has anti-platelet properties, which helps in the treatment for heart attacks and strokes.
  • 8. Classification of NSAIDs • Non selective COX inhibitors (conventional NSAID’s) • Salicylates: Asprin • Propionic acid derivatives: Ibuprofen, Naproxen, Ketoprofen, Flurbiprofen • Anthranilic acid derivative: Mephenamic acid • Aryl-acetic acid derivatives: Diclofenac • Oxicam derivatives: Piroxicam, Tenoxicam • Pyrrolo-pyrrole derivative: Ketorolac • Indole derivative: Indomethacin • Pyrazolone derivatives: Phenylbutazone, Oxyphenbutazone
  • 9. Classification of NSAID’s contd… • Preferential COX-2 inhibitors • Nimesulide, Meloxicam, Nabumetone • Selective COX-2 inhibitors • Celecoxib, Rofecoxib, Valdecoxib, Etoricoxib • Analgesics-antipyretics with poor anti inflammatory action • Para aminophenol derivative: Parcetamol (Acetaminophen) • Pyrazolone derivatives: Metamizol (Dipyrone), Propiphenazone • Benzoxazocine derivative: Nefopam
  • 11. Salicylates -Asprin • Is acetylsalicylic acid • Pharmacological actions • Analgesic, antipyretic, anti inflammatory actions • Analgesic action is due to prevention of PG mediated sensitization of nerve endings • Resets the hypothalamic thermoregulatory centre • Anti inflammatory at high doses • Blood • Long term use of large doses decreases synthesis of clotting factors in liver
  • 12. Aspirin • Respiration • Anti inflammatory doses – stimulates respiration • Hyperventilation in salicylate poisoning, in doses higher than this there is respiratory depression • Acid-base electrolyte balance • Adults treated with aspirin 4-6g/day stay in a state of compensated respiratory alkalosis • Still higher doses can cause respiratory acidosis • Dehydration occurs in poisoning due to increased urine output, sweating and hyperventilation • CVS • No direct effect in therapeutic doses
  • 13. Aspirin • GIT • Aspirin irritates gastric mucosa & causes epigastric pain, nausea and vomiting • ‘Acute ulcers, erosive gastritis, congestion and microscopic hemorrhages • Metabolic effects • Chronic use can cause negative nitrogen balance by increased conversion of protein to carbohydrate.
  • 14. Aspirin • Pharmacokinetics • Absorbed from stomach and small intestine • Precautions and contraindications • Contraindicated in patients sensitive to it and in peptic ulcer, bleeding tendencies. • In chronic liver disease • Asprin should be stopped 5 days before elective surgery, dental extraction • Pregnancy and lactating mothers
  • 15. Asprin • Adverse effects • Most important – gastric mucosal damage and peptic ulceration • Acute salicylate poisoning • Uses • As analgesic • As antipyretic • Acute rheumatic fever • Rheumatoid arthritis • Osteoarthritis
  • 16. Propionic acid derivatives • Pharmacokinetics • Well absorbed orally • Uses • Analgesic and Antipyretic and anti-inflammatory • Soft tissue injuries, tooth extraction, fractures, post operative pain. • Rheumatoid arthritis, osteoarthritis and musculoskeletal disorders… where pain is more prominent than inflammation
  • 17. Anthranilic acid dervative • Mephenamic acid- • Inhibits COX & antagonises certain actions of PG’s • Exerts peripheral as well as central analgesic action • Pharmacokinetics • Oral absorption is slow but complete • Adverse effects - Diarrhoea • Uses • Muscle, joint and soft tissue pain • Effective in dysmenorrhoea
  • 18. Beneficial actions due to PGBeneficial actions due to PG synthesis inhibitionsynthesis inhibition • Analgesia • Anti pyresis • Anti inflammatory • Anti thrombotic
  • 19. Routes of analgesic administration • Oral • Intramuscular Injection • Intravenous Injection • Other routes • Transdermal • Fentanyl patch • Sublingual • Morphine
  • 21. Classification of opioids • Natural opium alkaloids • Morphine, codeine • Semi synthetic opiates • Diacetylmorphine (heroin), pholcodeine • Synthetic opioids • Pethidine (meperidine), fentanyl, methadone, dextropropoxyphene, tramadol
  • 22. Morphine • Alkaloid of opium • Widely used • Pharmacological actions • CNS • Analgesia • Strong analgesic • Nociceptive pain arising from peripheral pain receptors is better relieved than neuritic pain • Reactions associated with intense pain – apprehension, fear are also depressed
  • 23. Morphine • CNS • Sedation • Drowsiness and indifference to surroundings as well as to own body , ataxia and apparent excitement also occur • Higher doses produce sleep and coma • Mood and subjective changes • Calming effect • Loss of apprehension, feeling of detachment,mental clouding and inability to concentrate
  • 24. Morphine • Respiratory and cough centres • Depresses Repiration and Cough centre • Temperature regulating and vasomotor centre • Depressed • CTZ(chemoreceptor trigger zone), vagal centre & certain cortical areas are stimulated • GIT • Constipation is a prominent feature
  • 25. Morphine • Neuro-endocrine • Enhances ADH release and so urine volume is reduced • Causes sympathetic stimulation – mild hypoglycemia • CVS • Causes vasodilation • Cardiac work is consistently reduced due to decrease in peripheral resistance
  • 26. Morphine • Pharmacokinetics • Oral absorption is unreliable – high and variable first pass metabolism • Freely crosses placenta, affects foetus more than the mother • Adverse effects • Mental clouding, sedation and lethargy • constipation • Acute morphine poisoning • Human lethal dose is 250mg . • Death is due to respiratory failure
  • 27. Morphine • Tolerance and dependence • Partly pharmacokinetic (enhanced rate of metabolism) but mainly pharmacodynamic (cellular tolerance) • Treated by substitution with oral methadone Precautions and contraindications • Infants and elderly • Bronchial asthma(wheezing) • Head injury •
  • 28. Codeine • Is methyl morphine • Less potent than morphine (1/10th as analgesic) • Is more selective cough suppressant
  • 29. Pethidine • Synthesized as an atropine substitute • Interacts with opioid receptors (mu) • Similar to morphine in most of its properties • Uses • As analgesic (substitute to morphine) • In pre anaesthetic medication
  • 30. Methadone • Chemically dissimilar but pharmacologically similar to morphine • Used • primarily as substitution therapy for opioid dependence • Also in methadone maintenance therapy
  • 31. Opioids in dental pain • Opioids are less effective and suitable than NSAID’s for dental pain • Mostly used as additional drugs with NSAID’s to boost their analgesic effect • Among opioids oral codeine is most suitable • Oral tramadol and pentazocine are alternatives
  • 32. Analgesics & Medical conditions • NSAIDs should be given in 2nd triemister of pregnancy and opioids should be avoided . • Paracetamol is the safest drug to use in pregnancy • Aspirin & Ibuprofen should not be given in asthmatic patients • Aspirin & Paracetamol should not be given in nephropathy(affected state of kidney) • Codein should not be used in renal dysfunction while fentanyl & methadone are safe .

Editor's Notes

  • #23: ORAL 10-50 mg tabs ( Morcontin ) QID IM or SC 10-15 mg/ml (Morphine sulphate) IV 2-6 mg
  • #24: ORAL 10-50 mg tabs ( Morcontin ) IM or SC 10-15 mg (Morphine sulphate) IV 2-6 mg
  • #25: ORAL 10-50 mg tabs ( Morcontin ) IM or SC 10-15 mg (Morphine sulphate) IV 2-6 mg
  • #26: ORAL 10-50 mg tabs ( Morcontin ) IM or SC 10-15 mg (Morphine sulphate) IV 2-6 mg
  • #27: ORAL 10-50 mg tabs ( Morcontin ) IM or SC 10-15 mg (Morphine sulphate) IV 2-6 mg Morphin poisoning – shallow breathing , cynosis , fall in BP , shock,convulsions, coma , death . Treatment of poisoning- Respiratory suppor with the help of ventilator , maintain BP with fluids and vasoconstrictors , gastric lavage with pot. Permangnate, Naloxone 0.4-0.8 mg IV repeated every 2-3 mins till resp picks up Nalorphine 3-5 mg IV
  • #28: ORAL 10-50 mg tabs ( Morcontin ) QID IM or SC 10-15 mg (Morphine sulphate) IV 2-6 mg Its shouldn’t be given in head injusry cause it increases intracranial pressure
  • #29: ORAL - 30-60mg tab Codein QID Combination with aspirin ORAL Codopyrin, Apidin  -- aspirin 325 mg + codein 30 mg
  • #30: Morphine causes respiratory depression hence not being used as a preanasthetic medication ORAL 100mg tab every 4 hourly IM 100mg/ 2ml injection every 4 hourly
  • #31: ORAL 20 mg TDS
  • #32: Opioids cause drug dependence , cns depression along with analgesic effect . Codein--- ORAL - 30-60mg tab Codein QID Combination with aspirin ORAL Codopyrin, Apidin  -- aspirin 325 mg + codein 30 mg Pentazocin --ORAL 30-60mg every 4 hrly Tramadol ---ORAL 100mg tab ( cotramol , domadol) IV 50mg / ml in 2 ml ampules IV morphine IM or SC 10-15 mg (Morphine sulphate) IV 2-6 mg pethidine IM 100mg/ 2ml injection every 4 hourly
  • #33: Miscarriage risk in first trimester Premature Ductus Arteriosus closure in third trimester Safe in preg Ibuprofen (Motrin) Indomethacin (Indocin) Ketoprofen (Orudis) Naproxen (Naprosyn) Piroxicam (Feldene) Sulindac (Clinoril) Aspirin is contraindicated coz there r chances of perinatal death , neonatal hemorg Asthma – nimesulide is preferential cox 2 and can be used