Substance abuse & toxicology Tikal


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Substance abuse & toxicology Tikal

  2. 2. PHYSIOLOGY OF SUBSTANCE ABUSE<br />Main addiction pathway is “Dopaminergic Pathway”.<br />Activation leads to “positive reinforcement” feeling and makes us want to repeat the action that triggers the feeling.<br />If there is an environmental stimulus, this pathway makes behavior adaptive and goal directed.<br />
  3. 3. Activated by all substances that have the tendency to produce dependence.<br />The most common examples are:<br />Gambling<br />Being in LOVE…<br />
  4. 4. NAC PATHWAY<br />
  5. 5. ROLE OF INSULA CORTEX<br />Anterior insula:<br />Direct projections from thalamus and amygdala<br />Project directly to amygdala<br />Amygdala important for emotional anticipation and conditional response<br />Functions<br />Conscious desires, “craving”<br />Damage to this area, example by stroke, addiction to cigrette smoking eliminated.<br />
  6. 6. ALCOHOLISM<br />Costs to US health system more than $ 100 billion per year.<br />Most common abused drug<br />Binge drinking has become more common and per capita drinking is declining<br />Implicated in:<br />Auto accidents<br />Homicides<br />Hospital admissions<br />
  7. 7. MEDICAL COMPLICATIONS<br />Fatty liver, Alcoholic hepatitis, Cirrhosis<br />Gastric & Duodenal ulcers<br />All complications of cirrhosis<br />Peripheral Neuropathy<br />Myopathies<br />Wernicke-Korsakoff Syndrome <br />
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  9. 9. FETAL ALCOHOL SYNDROME<br />Leads to mental retardation<br />Craniofacila abnormalities<br />Limb dislocation<br />
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  13. 13. TREATMENT<br />Behavioral modifications<br />Pharmacologic treatments<br />
  14. 14. BEHAVIORAL MODIFICATIONS<br />Psychotherapy and behavioral therapy useful<br />Stages of behavioral therapy:<br />Precomtemplation - unaware of the problem<br />Contemplation – aware but ambivalent about the action<br />Preparation – 1st decision to change<br />Action – change begins. Trial & error<br />Maintenance – new behaviors practiced. Focus on relapse prevention<br />Relapse – efforts to change abandoned.<br />
  15. 15. PHARMACOTHERAPY<br />Disulfiram (Antabuse)<br />Decreases alcohol consumption<br />Interaction with alcohol produces<br />Nausea, chest pain<br />Hyperventilation, tachycardia, vomitting<br />For short term use only<br />Must be accompanied with psychotherapy.<br />
  16. 16. MECHANISM OF ACTION OF DISULFIRAM<br />Disulfiram inhibits<br />Aldehyde dehydrogenase<br />Alcohol dehydrogenase<br />
  17. 17. OTHER DRUGS USED<br />ACAMPROSATE<br />Helps prevent relapse<br />Reduce activity of glutamate receptors (chronic alcoholism increases its activity)<br />Effect persists even after treatment has ended<br />
  18. 18. TOPIRAMATE (ANTICONVULSANT)<br />Helps support abstinence<br />Abstinence 6x more likelyy if not on any other drug for the last one month<br />
  19. 19. BENZODIAZEPINES (e.g. lorazepam)<br />Helps prevent seizures<br />Seizures occur during heavy drinking & also during detoxification<br />FLUMAZENIL<br />Benzodiazepine receptor antagonist<br />Can help prevent relapse.<br />
  20. 20. NALTREXONE<br />Given to recovering alcoholics<br />Reduces craving. Drinks don’t taste good. Helps them to stop the first drink<br />On naltrexone, relapse = 50%, if not, relapse = 95%<br />
  21. 21. TOBACCO INTOXICATION<br />Forms of tobacco intake are:<br /><ul><li>Chewing tobacco
  22. 22. Cigars
  23. 23. Hookahs
  24. 24. Snuff </li></li></ul><li><br />
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  26. 26. DRUGS OF ABUSE<br />The drugs of abuse are categorized as follows:<br />CNS stimulants<br />CNS depressants<br />Opioids<br />Hallucinogens<br />Miscellaneous Abused Drugs.<br />
  27. 27. CNS STIMULANTS<br />The most common drugs are:<br />Cocaine<br />Amphetamines<br />caffeine<br />
  28. 28. COCAINE & AMPHETAMINES<br />Amphetamines – Release DA, weak MAO-I<br />Cocaine – Prevent reuptake of DA, NE & 5HT<br />
  29. 29. COCAINE & AMPHETAMINES<br />
  30. 30. CAFFEINE<br />
  31. 31. CNS DEPRESSANTS<br />The most common drugs are:<br />Benzodiazepines<br />Barbiturates<br />Ethanol <br />Neurotransmitter involved : GABA<br />
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  33. 33. TREATMENT OF TOXICITY<br />Basic steps:<br />Gastric lavage<br />Supportive measures – patent airway, assisted respiration, oxygen, fluid infusion.<br />For barbiturate toxicity<br />Alkaline diuresis – jsod. Bicarb 1 mEq/kg IV with/without mannitol<br />Hemodialysis & hemoperfusion. <br />For BZD toxicity<br />Flumazenil 0.2 mg/min till patient regains consciousness<br />
  34. 34. OPIOIDS<br />Most common drugs of abuse are Morphine, Heroin, Methadone, Fentanyls and Other Opioids.<br />Activate opioid u, k & delta. Potent u receptor activators have the most abuse & dependence liability, via dopaminergic transmission.<br />
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  36. 36. HALLUCINOGENS<br />The most common hallucinogens are divided into two groups:<br />Cannabis<br />Marijuana<br />Hashish <br />Halucinogens<br />LSD<br />Ketamine<br />Mescaline <br />
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  39. 39. MISCELLANEOUS ABUSED DRUGS<br />PCP (Phencyclidine) – Horizontal & vertical nystagmus, paranoia, asssaultive, combative, agitated, violant behavior, decreased response to pain, psychosis.<br />MDMA (Ecstasy) - hallucinogenic<br />
  40. 40. ORGANOPHOSPHATE POISONING<br />Orgaanophosphates are irreversibly acting anticholinesterases<br />They are available as agricultural & household insecticides<br />Initial signs are of local manifestations & then signs of systemic involvement appears<br />
  41. 41. CLINICAL FEATURES<br />The very well known pneumonic is SLUDGE i.e.<br />Salivation<br />Lacrimation<br />Urination<br />Defecation<br />Gastric upset<br />Other symptoms include: fall in BP, brady/tachycardia, arrythmias, vascular collapse<br />Excitement, tremers, ataxia, convulsions, coma & death<br />
  42. 42. TREATMENT<br />Termination of further exposure to the poison – freash air, wash the skin & mucus membrane with soap & water, gastric lavage with NS or KMnO4 solution<br />Maintain airway, positive pressure ventilation if it is falling<br />Supportive measure – maintain BP, hydration, control of convulsions<br />
  43. 43. SPECIFIC ANTIDOTES<br />ATROPINE: Effective in counteracting muscarinic effects.<br />2 mg IV every 10 mins till symptoms subside or pupil dilation occurs<br />OXIMES: Used only for OP poisoninig. Pralidoxime(2-PAM) is given 1-2 gm slowly IV, but within 24 hours.<br />
  45. 45. KEY VIGNETTES<br />