Chapter 7- Drugs Affecting The Nervous System

Front 1

Neurons

Back 1

Sensory-toward CNS

Associative-between neurons

Motor-away from CNS

Front 2

Parts of the neuron

Back 2

Cell body.

Dendrite-impulse toward cell body

Axon-impulse away cell body

Front 3

Two parts of the nervous system

Back 3

CNS-central

PNS-peripheral

Front 4

CNS

Back 4

Brain and spinal cord.

Interpret impulses and send signals to PNS.

May increase or block activity.

Front 5

PNS

Back 5

12 cranial nerves.

Paired spinal nerves (Dorsal roots-sensory in, Ventral roots-motor out)

Autonomic nervous system (involuntary)

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Autonomic nervous system

Back 6

Sympathetic-adrenergic

Parasympathetic-cholinergic

Front 7

Sympathetic

Back 7

"fight or flight"-increases heart rate, etc.

Short preganglionic fibers, AcetylCholine neurotransmitter.

Long postganglionic fibers, epinephrine or norepinephrine.

Arise from thoracic and lumbar regions.

Front 8

Effects of Anticholinergic Drugs: "EAD"

Cardiac:

Back 8

Increases heart rate

Front 9

"EAD"

Vascular

Back 9

Causes vasoconstriction to digestive organs and skin and vasodilation to skeletal muscles.

Front 10

"EAD"

Bronchi

Back 10

Dilates bronchi and decreases bronchial secretions.

Front 11

"EAD"

Gastointestinal

Back 11

Relaxes smooth muscle tone of the GI tract, decreases GI motility and peristalsis, and decreases GI secretions.

Front 12

"EAD"

Urinary

Back 12

Relaxes urinary bladder muscles, increases constriction of the internal sphincter muscle of the urinary bladder, and causes urine retention.

Front 13

"EAD"

Ocular

Back 13

Causes mydriasis (pupillary dilation) and paralyzes the ciliary muscle.

Front 14

"EAD"

CNS/Muscular system

Back 14

Decreases muscle rigidity and can cause drowsiness and disorientation.

Front 15

"EAD"

Glandular

Back 15

Decreases salivation, perspiration, and tear production.

Front 16

alpha 1

Back 16

Effect-increases force of heart contraction, increases blood pressure, and causes mydriasis.

Blocking-Vasodilation and miosis

Front 17

alpha 2

Back 17

Effect-Inhibits release of norepinephrine and dilates blood vessels, producing hypotension

Blocking-None

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beta 1

Back 18

Effect-Increases heart rate and force of heart contraction

Blocking-decreases heart rate

Front 19

beta 2

Back 19

Effect-Dilates bronchioles and relaxes GI tract.

Blocking-Constricts bronchioles

Front 20

Parasympathetic

Back 20

"homeostatic". Normal heart rate, etc.

ACh released at both pre and postganglionic synapse. Long pre, short post fibers.

Fibers found in brain stem and sacral nerves.

Front 21

Effects of Cholinergic Drugs: "ECD"

Cardiac

Back 21

Decreases heart rate and slows conduction of the AV node.

Front 22

"ECD"

Vascular

Back 22

Causes vasodilation (lowers blood pressure)

Front 23

"ECD"

Bronchi

Back 23

Stimulates bronchial smooth muscle contraction and increases bronchial secretions.

Front 24

"ECD"

GI

Back 24

Increases motility of the smooth muscles of the stomach, increases peristalsis, and relaxes sphincter muscles.

Front 25

"ECD"

Urinary

Back 25

Contracts urinary bladder muscles, relaxes sphincter muscles of the urinary bladder, and stimulates urination.

Front 26

"ECD"

Ocular

Back 26

Causes miosis (pupillary constriction)

Front 27

"ECD"

Skeletal muscle

Back 27

Maintains muscle strength and tone

Front 28

"ECD"

Glandular

Back 28

Increases salivation, perspiration, and tear production.

Front 29

Seizures

Back 29

Periods of altered brain function due to recurrent abnormal electrical impulses in cerebral cortex

Front 30

Anticonvulsants

Back 30

Help prevent seizures by suppressing the spread of abnormal electric impulses from the seizure focus to other areas of the cerebral cortex.

All anticonvulsants are CNS depressants- May cause ataxia, drowsiness, and hepatotoxicity.

Front 31

Anticonvulsant Catergories

Back 31

Barbiturates-CNS depressants (phenobarbital)

Benzodiazepines-potentiate GABA (diazepam, Valium)

Potassium Bromide (KBr)-Chloride competitor

Phenytoin (Dilantin)-side effects limit use in animals

Add ons-used in small animals with refractory seizures uncontrolled by standard drugs

Front 32

Barbiturates

Back 32

Derivative of barbituric acid. Grouped by duration of action.

Long acting (6-8 hrs)-phenobarbital

Short acting (1-2 hrs)-pentobarbital

Ultrashort-(10-15 min)-thiopental, methohexital

Front 33

Phenobarbital (oral-Primidone)

Back 33

Long acting, anticonvulsant of choice in dogs and cats. C-IV controlled, IV or PO.

May cause liver enzymes (SAP, ALT) to rise, animal may develop tolerance.

Should take periodic blood samples for signs of liver damage.

Front 34

Pentobarbital

Back 34

Short acting, administered IV, C-11 controlled substance.

Commonly used as an euthanasia solution.

Front 35

Thiopental

Back 35

Ultra short. Administered IV for induction of anesthesia prior to intubation or for short procedures.

Front 36

Benzodiazepines

Back 36

Potentiate effects of GABA.

Used IV for status epilepticus.

diazepam (Valium), iorazepam (Ativan), clorazepate

Front 37

GABA

Back 37

Inhibitory neurotransmitter that stabilizes nerve cell membrane.

Front 38

Potassium bromide (KBr)

Back 38

Hyperpolarizes membrane, raises seizure threshold and limits spread of seizures. Long half life (24 days) takes several days to reach therapeutic range.

Front 39

Add-Ons

Back 39

Used for refractory seizures.

Front 40

Add-On-levetiracetam (Kappra)

Back 40

Dogs and cats with refractory epilepsy.

Binds to synaptic vesicle protein.

Side effects include sedation, ataxia, and anorexia.

Front 41

Add-On-zonisamide (Zonagran)

Back 41

Blocks calcium and sodium channels in the brain.

Facilitates serotonin and dopamine.

Side effects include ataxia and sedation.

Front 42

Add-on-gabapentin (Neurontin)

Back 42

Inhibits calcium channels resulting in decreased excitatory neurotransmission.

Side effects-sedation, ataxia, and potential hepatotoxicity.

Front 43

Add-on-felbamate (Felbatol)

Back 43

Used in dogs to control seizures by potentiating GABA and inhibiting calcium channels.

Side effects-hepatotoxicty, reversible blood dyscrasias, and keratoconjunctvitis sicca.

Front 44

Calming Agents

Back 44

Tranquilizers, Sedatives, Anti-anxiety drugs

Front 45

Phenothiazines (acepromazine)

Back 45

Sedation, antianxiety, antiemetic, antiarrhythmic, antihistamine effect, peripheral vasodilation, seizure threshold reducer.

Front 46

Butyrophenones (Not in U.S.)

Back 46

Sedation, Antiemetic

Front 47

Benzodiazepines (Valium, Telazol)

Back 47

Antianxiety, Muscle relaxant. No analgesia. Used with ketamine or tiletamine for short-term anesthesia.

Front 48

Alpha 2 Agonists (Xylazine)

Back 48

Sedation, Analgesic, Muscle relaxant, Emetic.

Premedicate with atropine (anticholinergic)

xylazine (Rompun)- most common

detomidine (Dormosedan)- used for colic in horses.

Domitor & Dexdomitor-sedation and analgesia in dogs. IM or IV. Reversed with atipamezole, (Antisedan)

Front 49

Phenothiazine derivatives

Back 49

Causes sedation, relieves fear and anxiety.

acepromazine-(Promace)

chlorpromazine-(Thorzine)

compazine

promazine-(Sparine)

Front 50

xylazine (Rompum)

Back 50

Combined with ketamine for short term procedures. Emetic. Can be reversed with yohimbine or tolazoline.

IMPORTANT: Always check Rompum label for dosage concentration. Large animal is 100mg/ml, small is 20.

Front 51

Analgesia (Pain Relief)

Classified as:

Back 51

Physiologic: the bodies protective mechanism to avoid tissue injury.

Pathologic: arises from tissue injury and inflammation or from damage to nervous system.

Front 52

Analgesia can be further divided into:

Back 52

Nociceptive: transient pain due to peripheral tissue injury.

Neuropathic: damage to the peripheral nerves or central nervous system.

acute/chronic

Front 53

Nociceptive pain

Back 53

Somatic Pain-arises from joint, bone, muscle, skin, or connective tissue.

Visceral Pain-arises from visceral organs

Front 54

Neuropathic Pain

Back 54

Centrally generated pain-peripheral or central nervous system injury. Dysregulation of the ANS

Peripherally Generated Pain-Peripheral nerve injury.

Front 55

Nociceptive Pain Pathway

Back 55

Transduction-Stimulus to electrical energy

Transmission-Through PNS to spinal cord, brain

Modulation-What CNS does with pain signal

Perception-Awareness

Front 56

Signs of pain

Back 56

abnormal, licking, biting, changes, etc.

Front 57

Analgesics

Back 57

Non or narcotic.

Preemptively-before pain starts

Multimodally-combining drugs from different classes to achieve synergism.

Front 58

Narcotics

Back 58

Refers to opiate (natural from opium poppy seeds) or opioid-like (synthetic). Work on CNS.

Front 59

Non-Narcotics

Back 59

Used for mild to moderate pain, are non-addictive, and work on the PNS receptors.

Front 60

Opoids

Back 60

Do not produce anesthesia. Produce analgesia and sedation, and relieve anxiety.

Described by their action at the opioid receptor.

Side effects: respiratory depression, excitement if given too rapidly.

Front 61

Mu

Back 61

Found in the pain area of the brain and spinal cord.

Front 62

Kappa

Back 62

Found in the cerebral cortex and spinal cord

Front 63

Delta

Back 63

Found in the brain, spinal cord, provide minimal analgesia in animals.

Front 64

Affinity

Back 64

Drug's ability to bind with a receptor.

Affects a drug POTENCY.

Front 65

Activity

Back 65

Ability of drug to cause action in or on receptor cell.

Front 66

Based on affinity and activity, opioids are:

Back 66

Full agonists-bind to receptor & produce effect.

Partial agonists-potent activity

Full antagonists- No activity

Partial antagonists-reversal agents

Front 67

Opioids

Back 67

Opium, Morphine sulfate, hydromorphone, butorphanol, hydrocodone, fentanyl, etorphine, buprenorphine, pentazocine, methadone, codeine, tramadol, diphenoxylate, loperamide, apomorphine.

Front 68

Opium

Back 68

C-lll, paregoric in tincture. Natural opioid, antidiarrheal in calves and foals.

Front 69

Morphine sulfate

Back 69

C-ll, inject or oral. Naturally occurring, affects mu and kappa receptors. Treats severe pain, preanesthetic, anesthetic, emetic

Front 70

Hydromorphone

Back 70

(Dilaudid) IV, IM, SQ pre-op. Semisynthetic mu agonist, C-ll, 5x more potent than morphine, also treats severe post-op pain

Front 71

Butorphanol

Back 71

(Torbugesic) (Torbutrol) C-lV. Synthetic opioid, 2-5x analgesia of morphine. Potent antitussive, analgesic, preanesthetic. Comes in small animal and horse concentrations.

Front 72

Fentanyl

Back 72

(Duragesic). Transdermal, IV, tablet. Synthetic, transdermal patch, C-ll, 200x morphine

Front 73

Etorphine

Back 73

(M-99) for immobilization of zoo and exotic animals, C-ll, 1000x morpine

Front 74

Tramadol

Back 74

(Ultram) Centrally acting opioid agonist with mu receptor activity, SSRI. Used to control chronic pain, for oral analgesia and antitussive.

Front 75

Loperamide

Back 75

(Immodium) antidiarrheal

Front 76

Opioid Antagonists

Back 76

Blockers. Used to treat respiratory and CNS depression. Naloxone. Naltrexone

Front 77

Naloxone

Back 77

a opioid antagonist used to reverse respiratory depression following narcotic overdose, given IV, IM, SQ

Front 78

Naltrexone

Back 78

used to treat behavior disorders and chronic licking

Front 79

Neuroleptanalgesics

Back 79

combination of an opioid and a tranquilizer or sedative to relieve pain and calm anxiety. No longer available commercially.

Front 80

Anesthetics

Back 80

Anesthesia- means without sensation- NO PAIN

Front 81

Local Anesthetics

Back 81

Block pain at site.

Examples: lidocaine, proparacaine, tetracaine, mepivacaine, bupivacaine.

Front 82

Types of Local Anesthesia

Back 82

Infiltration, Topical, Nerve block, Line block, Regional (epidural)

Front 83

Injectable general anesthetics (1)

Back 83

Barbiturates: CNS depressants derived from barbituric acid. Used mainly as anticonvulsants, anesthetics, and euthanasia solutions.

Side effects: potent cardiovascular and respiratory depression.

Front 84

Injectable general anesthetics (2)

Back 84

Dissociatives: belong to the cyclohexamine family (PCP, angel dust)

Examples: ketamine and tiletamine.

Front 85

Misc. Injectable general anesthetics

Back 85

-Guaifenesin: Skeletal muscle relaxant used in combo with an anesthetic drug to induce general anesthesia in horses.

-Propofol: short acting inj. anesthetic agent that produces rapid and smooth induction when given IV.-Side effects-cardiac arrhythmias and apnea. Hypnotic agent.

Front 86

Inhalant General Anesthetics

Back 86

"Volatile anesthetics"

Compared on value called MAC-minimum alveolar concentration. Measure of the strength of anesthetic.

Lower MAC= More potent (halothane)

Higher MAC= Less potent (isofluorane)

Front 87

Blood-to-gas solubility

Back 87

Hi BGS= longer induction, longer recovery

Low BGS= faster induction and recovery

Front 88

Methods of Administering Anesthetics by Inhalation

Back 88

Open-drop, semi-closed, closed

Front 89

Inhalant general anesthetics (1)

Back 89

Halothane (Fluothane). Nonflammable, inhalant anesthetic administered via a precision vaporizer. Leave animals on 100% oxygen following surgery to prevent diffusion hypoxia.

Front 90

Inhalant general anesthetics (2)

Back 90

Isoflurane (Isoflo). Nonflammable, inhalant anesthetic administered via a precision vaporizer.

Side effects include respiratory depression and malignant hyperthermia.

Front 91

Inhalant general anesthetics (3)

Back 91

Isomers of isoflurane. Nonflammable and have fewer cardiovascular side effects than other inhalants. C-sections.

Examples: Enflurane, Desflurane, Sevoflurane-side effect profound respiratory depressant, close monitoring needed.

Front 92

Inhalant general anesthetics (4)

Back 92

Sevoflurane: produces rapid induction and rapid recoveries. Produce fewer cardiovascular side effects. Has low tissue solubility, resulting in rapid elimination of the drug by the body.

Front 93

CNS Stimulants

Back 93

Reverse CNS depression caused by CNS depressants.

Doxapram: (Dopram V)-C-sections, sublingual drop or via umbilical cord.

Methylxanthines: bronchodilators. Include caffeine, theophylline, and aminophylline. Considered performance-enhancing

Front 94

Euthanasia Solutions

Back 94

Used to humanely end an animal's life. When pentobarbital is in combo with other agents, it is a C-lll controlled substance (Beuthanasia-D)

Front 95

ANS drugs

Back 95

Autonomic nervous system drugs work either by acting like neurotransmitters or by interfering with neurotransmitter release.

Front 96

Two groups of drugs affect the parasympathetic nervous system

Back 96

Cholinergics (parasympathomimetics)-mimic the action of the parasympathetic nervous system.

Anticholinergics (parasympatholytics)

Front 97

Two groups affect the sympathetic nervous system.

Back 97

Adrenergics (sympathomimetics)

Adrenergic blockers (sympatholytics)

Front 98

Anticholinergic Drugs

Back 98

Inhibit the actions of acetylcholine by occupying the acetylcholine receptors.

Examples:atropine

Used to decrease salvation during anesthesia.

Front 99

Adrenergic Drugs

Back 99

Simulate the action of the sympathetic nervous system. Examples: epinephrine, norepinephrine, dobutamine, albuterol.

Front 100

Adrenergic Blocking Agents

Back 100

Block the effects of the adrenergic neurotransmitters.

beta-blockers include propranolo, metoprolol, and timolol.