Anticonvulsants Part 3 (Convulsants, Stimulants) Flashcards

1
Q

Name the 3 convulsants

A
  1. pentylenetetrazole (Metrazole)
  2. strychnine
  3. picrotoxin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which of the 3 convulsants blocks GABA receptors

A

picrotoxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which of the 3 convulsants decreases neuronal recovery time by increasing K permeability

A

pentylenetetrazole (Metrazole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define the action of strychnine

A

blocks glycine receptors on Renshaw cells (postsynaptic inhibition)

  • Produces a generalized convulsion
  • Added to heroin and causes overdose
  • Rat poison
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define the action of picrotoxin

A
  • Blocks GABA receptors
  • Blocks GABA-induced increased chloride conductance and decreasing cAMP concentrations
  • Produces conic convulsions by blocking presynaptic inhibition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define action of pentylenetetrazole (Metrazole)

A

Decreases neuronal recovery time by increasing K permeability
- **Used for provocative diagnosis of epilepsy
- General cortical convulsant
Keeps people awake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Indication for Stimulants

A

Used as an antidote for depression = analeptics

  • No one drug that is very effective
  • ***Primarily used to reverse respiratory, cardiac and CNS depression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an analeptic

A

a drug that acts as a restorative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Primary classes of stimulants

A
  1. Xanthenes
  2. Centrally acting sympathomimetics
  3. Convulsants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

General use for Xanthenes

A

Primarily used for asthma to reverse respiratory depression (Bronchodilators)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

General use for centrally acting sympathomimetics

A

Used primarily for hyperkinetic children

- Amphetamine is prototype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

2 drugs for asthma, chronic bronchitis, COPD (Xanthene)

A

aminophylline

theophylline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How much caffeine or theophylline is needed to increase cortical activity? How much is in an OTC stimulant?

A

50-200 mg (1 to 4 cups of coffee)

-*** OTC stimulants have 100-200 mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

CNS and respiratory stimulation in order of potency

A
  1. Cerebral Cortex = 50-200 mg (Small dose produces effect = more potent)
  2. Brain Stem = >250 mg (greater dose required)
  3. Spinal cord = 1000 mg (highest dose required –> **Can lead to convulsions, shakiness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Summary of Pharmacological Effects by potency/Efficacy

A
CNS -->   caffeine = theophylline
BV -->    theophylline > caffeine
Heart -->    theophylline > caffeine
SM musc -->    theophylline > caffeine
SK musc -->     caffeine > theophyline
Diuresis -->    theophylline > caffeine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the Blood vessel dilation effects of Xanthenes

A
  1. Blood vessel dilation (dilation in coronary and peripheral blood vessels) **BETA 2 Effect
    • caffeine decreases peripheral resistance
    • Can make someone hypotensive
    • **theophylline more potent than caffeine
  2. Blood vessel Constriction (cerebral blood vessels)
    • Treatment for headache
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the Cardiac Muscle stimulation effects of Xanthenes

A

Beta 1 effect

  • **Increases cardiac output
  • theophylline more stimulatory than caffeine
  • theophylline = inhibits ADH which increases perfusion
  • caffeine = hypotension (smooth muscle relaxation of vasculature in periphery), normal heart rate
  • ** caffeine will cause arrhythmias in someone who is at risk for arrhythmias but does not produce arrhythmias in a normal heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the Smooth muscle relaxation effects of Xanthenes

A

Beta 2 effect

  • Bronchial dilation; increases lung capacity to facilitate breathing
  • theophylline more potent than caffeine
  • *** theophylline is a popular asthma medication
19
Q

Describe the Skeletal muscle effects of Xanthenes

A

Skeletal muscle contraction
- Caffeine more stimulatory than theophylline
- **Pain stiffness, psychic tension in neck
Causes by permeability to Ca in skeletal muscle (Contracts more than it normally would)

20
Q

Describe the Diuresis effects of Xanthenes

A

theophylline more potent than caffeine

  • increased glomerular filtration rate
  • inhibits ADH
  • Increased perfusion to kidney
21
Q

Adverse reactions of Xanthenes

A
  1. CNS
  2. GI
  3. CVS - hyoptension
  4. Habit forming
22
Q

How much caffeine is needed to produce toxicity

A

300 mg required

23
Q

Withdrawal syndrome begins how soon after discontinuance with caffeine

A

wihtin 24 hours

24
Q

2 OTC caffeine preparations

A

No Doz = 100 mg caffeine per tablet; recommended dose is 2 tablets

Vivarin = 200 mg caffeine tablet

25
Q

Therapeutic uses of xanthenes

A

1- Asthma, chronic bronchitis, COPD, status asthmaticus
2- Maintains wakefulness, overcomes mild depression of CNS caused by fatigue, alcohol and sedatives
3- Some CNS depressant poisonings (Opioid poisoning)
4- Migraines - caffeine used with analgesics
5- Treatment of acute pulmonary edema and apnea in preterm infants
6- Diuretic (increases kidney perfusion, inhibits ADH)

26
Q

T or F, Xanthenes are very effective in treating alcohol OD and may help to overcome mild opiate OD

A

1st statement False: not effective in treating alcohol OD

2nd statement True

27
Q

Mechanism of Action for CNS Sympathomimetics

A
  • Direct alpha 1 or dopamine receptor agonists
  • MAO inhibitors
  • Re-uptake inhibitors
  • Presynaptic releasers of endogenous catecholamines
28
Q

Effects of CNS sympathomimetics

A
  1. Decrease fatigue
    • They don’t improve performance just allow you stop stay awake for longer
  2. Reduces rapid eye movement (REM)
  3. Produces psychic depression, parania
  4. May depress appetite
  5. Stimulates medullary respiratory center
29
Q

Indications for CNS sympathomimetics

A
  1. Narcolepsy - only good therapeutic indication (30 mg/kg)
  2. Hyperkinetic syndromes (hyperactivity)
    • Can’t concentrate for long periods of time.
30
Q

Adverse effects of CNS sympathomimetics

A
  1. Acute toxicity - Xerostomia, irritability, palpitations, etc.
  2. Chronic toxicity - Psychosis resembling paranoid schizophrenia
  3. Dependency/addiction
31
Q

Action of Cocaine

A

Blocks sodium/potassium ATP-ase reuptake mechanism

  • Dopamine and NE remains in the synapse
  • Rapid onset of sympathetic effects
  • Reaches CNS and *causes euphoria
  • Crosses blood brain barrier, which increases sympathetic effects
32
Q

Drugs for ADHD

A

Adrenergic agonists = CNS stimulation
- methylphenidate (Ritalin) –> blocks repute of dopaminergic neurons

Stimulants
- dextroamphetamine (Dexadrine)

Selective norepinephrine reuptake inhibitor
- atomoxetine (Straterra)

33
Q

What should you avoid with Ritalin

A

vasoconstrictors

34
Q

Action of Dexadrine

A
  • blocks the repute of dopamine and norepinephrine
  • inhibits monamine oxidase
  • Enhances sympathomimetic response of epinephrine/norepinephrine = avoid vasoconstrictor
35
Q

Action of atomoxetine (Straterra)

A

Selectively inhibits repute of norepinephrine with little to no activity at other repute or receptor sites
- May increase heart rate and blood pressure in presence of a pressor agent = use vasoconstrictor with caution

36
Q

Name the 3 specific amphetamines

A
  1. amphetamine (Benzedrine)
  2. dextroamphetamine (Dexedrine) = Narcolepsy
  3. ephedrine (Pretz-D)
    • Cough and cold medications to relieve bronchial and nasal congestion
37
Q

Amphetamines pulled from market

A

phenylpropanolamine (PPA)
- Deaths from heart attack and stroke

ephedra

- Deaths from heart attack and stroke
- Stimulatns for performance enhancement
38
Q

Amphetamines stimulate what nervous system?

A

Sympathetic nervous system - many cardiac effects

39
Q

T or F, Use caution when administering local anesthetics with vasodilators to patients using these drugs

A

False, vasoconstrictors

40
Q

Action of doxapram (Dopram)

A

Selectively stimulates respiratory centers

41
Q

Indication of doxapram (Dopram)

A

Sold as parenteral drug to reverse general anesthesia or drug-induced respiratory depression
- also used to treat apnea in infants

42
Q

Action of Nicotine

A

low doses of nicotine from smoke stimulates nicotinic receptors in brain stem and cortex, even though most cholinergic receptors in brain are muscarinic

43
Q

T or F, higher concentrations of nicotine cause convulsions, which can be fatal. One of the most addicting substances known

A

True