Pharmacology - Drugs affecting the Nervous System Toxicology

  1. List the AED's which work by blocking off the sodium channels (4)
    • Phenytoin
    • Carbamezepine & Oxcarbazepine
    • Lamotrigine
    • Valproic Acid
  2. What is the difference between new AEDs and old AEDs
    • same efficacy
    • Newer drugs are more expensive and have fewer side effects
  3. What do you use to treat absence seizures?
  4. What is the loading and maintenance dose for phenytoin (Dilantin)?
    Load: 15-20 mg/kg first. If no response in 20 mins add another 10 mg/kg

    Maintenance dose: 5 mg/kg/day
  5. Why might carbamazepine stop working after a few months?
    It induces its own metabolism.
  6. When should you NOT give carbamazepine and oxcarbazepine?
    They may worsen absence and myoclonic seizures. Some Asian people may have a people that causes SJS
  7. What AEDs should be avoided in pregnancy (3)? What is important that they be supplemented with? How much?
    Valproic acid, phenytoin, and barbituates (e.g. penobarbitol). Give 4mg vit D daily.
  8. Which AEDs potentiate the effects of GABA? (2)
    • Benzodiazepines (lorazepam and diazepam)
    • barbituates (phenobarbitol)
  9. what is phenobarbitol especially good at treating?
    neonatal seizures
  10. What are 2 CCB AEDs?
    • ethosuximide
    • Valproic Acid
  11. What AED binds to synaptic vesicles and prevents the release of neurotransmitters?
    Levetiracetam (Keppra)
  12. Common side effects in AEDs (8)
    • -N/V
    • -sedation
    • -ataxia
    • -rash
    • -hyponatremia
    • -weight fluctuation
    • -Teratogenicity
    • -Osteoporosis
  13. Which AEDs help with both focal and generalized seizures (5)?
    • -valproic acid
    • -lamontrigine
    • -Levetiracetam (Keppra)
    • -Zonisamide
    • -Benzodiazepines
  14. Which AEDs should you only use for focal seizures?
    • -Phenytoin
    • -Carbamazepine
    • -Oxcarbazepine
  15. How many mg's of oral morphine would you need to give to match 10 mg IV morphine? 40 mg of oral codeine?
    • 30 mg
    • 4 mg
  16. How much more potent is hydromorphone (dilaudid) than morphine?
    • oral: 7.5x more potent
    • Subcutaneous: 5x more potent
  17. Adverse effects observed in tmt with opioids (6)?
    • -sedation
    • -constipation
    • -nausea
    • -urinary retention
    • -addiction
    • -resp depression (this is what kills)
  18. Why is methadone good to treat addiction to opioids?
    It has a long half life (35 hours)
  19. What are two drugs you can give someone you is ODing on opioids? What is their MOA?
    • Naloxone
    • Naltrexone

    Both are EOP receptor antagonists
  20. Describe the overarching MOA of opioids?
    • activation of the opioid receptors:
    • -decreases Ca++ inflow into presynaptic neuron (decreases release of neurotrans)
    • -Increases K+ outflow in the postsynaptic neuron (Hyperpolarizes the cell)
  21. Describe the role of prostaglandins in pain and inflammation
    • 1) sensitize nociceptors to pain, physical, and thermal stimulii
    • 2) increase blood flow to injured tissues, increasing leukocyte infiltration and thereby increasing edema and inflammation
  22. Name two selective cox II inhibitors
    • -Celecoxib (celebrex)
    • -Rofecoxib (Vioxx)
  23. List the 4 main adverse effects in NSAIDS due to inhibiting cox 1
    • 1) GI effects (ulcers)
    • 2) decreased blood coagulation
    • 3) bronchoconstriction
    • 4) decrease renal blood flow
  24. Besides inhibiting the breakdown of dopamine, how to MAO-B inhibitors help with parkinsons?
    Decrease free radicals produced by the breakdown of dopamine. This spares the SN neurons from being broken down.
  25. Describe the Sympathiomimetic Toxidrome (6) Which three are the same as the anticholinergic toxidrome?
    • -tachycardia
    • -hypertension
    • -febrile
    • -Agitated/violent
    • -dilated pupils (reactive though)
    • -Sweaty

    First three are the same as the AC toxidrome
  26. What is the antidote for someone who is having an OD from a sympathiomemetic (e.g. meth)?
    -Midazolam (a benzo that calms the ANS)
  27. Describe the anticholinergic toxidrome (8)
    • Features that are the same as sympathiomimetic toxidrome:
    • -tachycardia
    • -HTN
    • -fever

    • Others
    • -dilated pupils (non-reactive)
    • -hallucinations
    • -dry skin
    • -absent bowel sounds
    • -urinary retention
  28. How do you treat someone who has OD'd on an anticholinergic (e.g. gravol)?
    Supportive care usually, usually don't give an AChEi
  29. Describe the opioid toxidrome (4)
    • -Resp rate depression (<12)
    • -Altered mental status -> coma
    • -pinpoint pupils
    • -absent bowel sounds
  30. How do you treat an opioid OD? how much?
    give them Narcan, just enough to bring up their RR so that you don't need to intubate
  31. Describe the Benzo toxidrome (2). How do you differentiate it from an opioid presentation
    • -resp depression
    • -altered metal status -> coma

  32. How do you usually treat a benzo OD?
    Supportive care
  33. Describe the cholinergic toxidrome (7)
    • DUMBELS mnemonic
    • Diarrhea
    • Urination
    • Miosis
    • Killer B's: Bradycadria, Bronchorrhea, Bronchospasm
    • Emesis
    • Lacrimation
    • Salivation
  34. What is the antidote for someone having a cholinergic OD (e.g. a farmer with pesticide exposure)
    give an anticholinergic like atropine
  35. Describe three tmts that are used in decontamination. What should NOT be used?
    • -Activated charcoal
    • -Whole bowel irrigation
    • -Gastric Lavage

  36. When should you get a urine tox screen?
    Basically you shouldn't order this. It doesn't change your management and can have a ton of false positives. Make a clinical diagnosis AND GET A SERUM ACETAMINOPHEN LEVEL!
  37. Describe the normal metabolism of tylenol. What happens in a tylenol OD
    Normally 85-95% of tylenol is metabolized by Kidney, sulfation, and glucoronidation. 5-15% is oxidized in the liver and produces NAPQI, which damages the liver. This is normally handled by glutathione.

    In an OD all the other pathways become saturated and there isn't enough glutathione to handle all the NAPQI being made. Liver failure.
  38. How do you treat a Tylenol OD? MOA?
    • -CATCH IT EARLY (takes time for hepatic damage to occur so you have a bit of a window)
    • -N-acetylcysteine
    • -It replenishes the glutathione
Card Set
Pharmacology - Drugs affecting the Nervous System Toxicology
Pharmacology - Drugs affecting the Nervous System, Toxicology