This document provides an overview of various drugs that affect the nervous system, organized by drug class. It begins with analgesics like opioids, salicylates, and NSAIDs. It then covers anesthetics, anti-anxiety drugs, anti-seizure medications, CNS stimulants, and psychotherapeutics. For each class, it lists example drugs and briefly describes their mechanisms of action and effects. The document also discusses drugs that affect the autonomic nervous system, including cholinergic and anticholinergic agents.

1. Drugs That Affect The: Nervous System

3. But first... A colorful review of neurophysiology!

4. Nervous System CNS PNS Somatic Autonomic Parasympathetic Sympathetic

7. Actions of Opioid Receptors Response Mu Kappa Analgesia   Respiratory Depression  Sedation   Euphoria  Physical Dependence   GI motility  

8. Actions at Opioid Receptors Drugs Mu Kappa Pure Agonists -morphine, codeine, meperidine (Demerol ® ), fentanyl (Sublimaze ® ), remifentanil (Ultiva ® ), propoxyphene (Darvon ® ), hydrocodone (Vicodin ® ), oxycodone (Percocet ® ) Agonist Agonist Agonist-Antagonist - nalbuphine (Nubaine ® ), butorphanol (Stadol ® ) Antagonist Agonist Pure Antagonist - naloxone (Narcan ® ) Antagonist Antagonist

11. NSAID Properties Drug Fever Inflammation Pain Aspirin    Ibuprofen    Acetaminophen  

15. Acetaminophen Metabolism Acetaminophen Non-toxic metabolites Major Pathway Minor Pathway P-450 Toxic metabolites Non-toxic metabolites Induced by ETOH Glutathione Depleted by ETOH & APAP overdose

20. Benzodiazepines vs. Barbiturates Criteria BZ Barb. Relative Safety High Low Maximal CNS depression Low High Respiratory Depression Low High Suicide Potential Low High Abuse Potential Low High Antagonist Available? Yes No

22. Barbiturates Subgroup Prototype Typical Indication Ultra-short acting thiopental (Pentothol ® ) Anesthesia Short acting secobarbital (Seconal ® ) Insomnia Long acting phenobarbital (Luminal ® ) Seizures

27. Where Does Diffusion Take the Ion? Exterior Interior K + 5 mM Cl - Low Cl - High K + 150 mM Na + 15 mM Na + 150 mM O U T I N I N

28. Action Potential Components Membrane Potential (mV) -50 -70 0 +30 Time (msec) Threshold Potential Resting Membrane Potential Na + equilibrium Action Potential Depolarization! Hyperpolarized

29. Membrane Permeability Membrane Potential (mV) -50 -70 0 +30 Time (msec) Threshold Potential Resting Membrane Potential Na + Influx K + Efflux

30. What Happens to the Membrane If Cl - Rushes Into the Cell During Repolarization? Membrane Potential (mV) -50 -70 0 +30 Time (msec) Threshold Potential Resting Membrane Potential Na + Influx K + Efflux It gets hyperpolarized!

31. What Happens to the Frequency of Action Potentials If the Membrane Gets Hyperpolarized? Membrane Potential (mV) -50 -70 0 +30 Time (msec) It decreases!

33. Gamma Amino Butyric Acid Receptors GABA Receptor Exterior Interior Cl - Hyperpolarized!

34. GABA+Bz Complex Bz Receptor GABA Receptor Exterior Interior Cl - Profoundly Hyperpolarized!

35. Are You Ready for a Big Surprise? Many CNS drugs act on GABA receptors to effect the frequency and duration of action potentials!

40. A patient is taking theophylline and becomes tachycardic (SVT). You want to give her adenosine. Is there an interaction you should be aware of? How should you alter your therapy? Methylxanthines blocks adenosine receptors. A typical dose of adenosine may not be sufficient to achieve the desired result. Double the dose!

47. Extrapyramidal Symptoms Reaction Onset Features Acute dystonia Hours to 5 days Spasm of tongue, neck, face & back Parkinsonism 5 – 30 days Tremor, shuffling gait, drooling, stooped posture, instability Akathesia 5 – 60 days Compulsive, repetitive motions; agitation Tarditive dyskinesia Months to years Lip-smacking, worm-like tongue movement, ‘fly-catching’

56. MAOI & Dietary Tyramine

57. Antidepressant Mechanism TCAs & SSRIs Block Here

60. Parkinson’s Disease

64. Levodopa Mechanism

66. Drugs That Affect the Autonomic Nervous System Word of Warning Carefully review the A&P material & tables on pages 309 – 314 and 317 – 321!

68. Acetylcholine Receptors Figure 9-8, page 313, Paramedic Care, V1

82. Adrenergic Receptor Specificity Drug α 1 α 2 β 1 β 2 D opaminergic Epinephrine Ephedrine Norepinephrine Phenylephrine Isoproterenol Dopamine Dobutamine terbutaline