CNS Pharma Flashcards
Importance of drugs on CNS
Action of neurotransmitter and or receptors contributes to therapeutic benefit /side effects
Can enhance or diminish action of endogenous neurotransmitters
- kinetic differences can include route/rate of elim
Agonist action at receptor
Direct
Indirect (increases action of exogenous neurotransmitter, often by decreasing degredation)
Antagonist action at receptor
Direct (comp inhibition)
Indirect antagonist decease availability of neurotransmitter
Conduction pathways in CNS
Excitatory or inhibitory, redundant or not
5 major processes identifying a neurotransmitter
1 - synthesis
2 - storage
3 - release
4 - receptor interaction
5 - inactivation
Ionotropic receptors
GABA, glutamate, ACh
Send electrical signals, short term effect
Metabotropic receptors
GABA, opioids, monoamines (norepinephrine, DA, Serotonin) also ACh
Only Ionotropic receptor
Glutamate
Why do not all patients respond the same when administered the same drugs?
Glutamate can make gaba
GABA can make glutamate
GABA = inhibitory
Glutamate = excitatory
T/F
Neurotransmitters of the peripheral nervous
system (ANS) can also be neurotransmitters of the CNS.
True
Synthesis and degradation of glutamate and
GABA are interrelated.
True
Dopamine, norepinephrine and serotonin have similar synthetic pathways.
True
- Identified CNS neurotransmitters are routinely
modulated for therapeutic purposes.
True
Glutamate
Excitatory
Pain perception
Overstimulation detriments - seizures, brain damage
Multiple sites on this Ionotropic receptor for drugs
- glutamate, glycine, aminoglycosides antibiotics, hallucinogens
Antagonist used as dissociative anesthetic
- ketamine
GABA
Amino acid neurotransmitter
Inhibitory
2 receptors, GABAa (Cl- channel) GABAb
Structural analogs for pain modification (gabapentin, NOT GABAa receptor targeting)
GABA receptor agonist drugs are tranquilizers, anticonvulsants/muscle relaxants, anesthetics
- benzodiazepines (oral IV)
- barbiturates (oral IV)
- general anesthetics (inhalants, IV) low safety margin
Ketamine
Could be aware but not able to move, only comes in injectable form
Good for cardiac risk clients
Drugs for Ionotropic receptors
Glutamate, glycine, aminoglycosides, antibiotics, hallucinogens
Receptors for gaba
GABAa - cl - channels
GABAb
Drugs that target GABA
Benzodiazepines (oral IV)
Barbiturates (oral IV)
General anesthetics (inhalants, iV)
What GABA drugs are controlled drugs?
Class III, class IV
Barbiturates - cause respiratory depression
Benzodiazepines - muscle relaxants
Why are obese patients risky for dosing?
All drugs are lipid soluble, drugs linger in fat, just because drugs aren’t present in blood concentration could still be too high
- lower secondary dose
Opioids
Enkephalins, endorphins are endogenous neuropeptides w role in tolerance to pain
Opioid drugs
Agonist used for analgesia
- mu, kappa receptors - full and partial agnoists
- respiratory & cardio depressants, antitussives, emetics
- antagonist
- oral, parenteral & topical preparations
Action of opioids
Act on presynaptic sensory neurons to reduce pain causing neurotransmitter release
What drug targets Kappa receptors?
Tramadol
Biggest risk to opioids
Respiratory depression
Analgesic action
Weak bases of opioids
Lipophilic, low margin of safety
Dose response for resp t and cardio depression
PK of opioids
Oral or parenteral, microsomal metabolism
Urinary excretion, variable duration based on route/formulation
Metabotropic receptors of opioids
Mu, Kappa
Antidotes - competitive antagonist
Use of opioids
Analgesics, emetics, antitussives, vet sedatives
Controlled substances (class III)
T/F All receptors for GABA, glutamate and natural opioids are ionotropic
False
- T/F Drugs that are agonists at GABA, glutamate and enkephalin receptors act at the same site on the receptors as the natural neurotransmitters.
False
- T/F Excitatory and inhibitory pathways can stimulate the same postsynaptic neuron.
True
T/F Relief of pain occurs because opioid analgesics have a direct effect on neurotransmitter release
False
Act on Ca channels blocked
Monoamines
Dopamine, norepinephrine, serotonin
Features of monoamines
Multiple roles/receptors - role in direct agonist
Nonspecific action with indirect agonist
- action on degredation enzymes
- nonspecific reuptake inhibition
More specific action w direct agonist and drugs are more specific reuptake inhibitors
Role of monoamines in disease and treatments
Analgesics
Disorders of behavior
Chemical restrains/tranquil
Emesis/antiemetics
Functions drugs can alter
Release, receptors, enzymes of degredation, reuptake
Monoamine agonists
Norepinephrine
Alpha 1 - stimulates
Alpha 2 - analgesics, tranq, antihypertensives, emetics in cats
Monoamine antagonist
Dopamine
Antiemetics
- phenothiazine - antihistaminic & anti cholinergic action
Metocolpramide - antagonists, prokinetic agent
Vet use of Monoamine antagonist
Tranq and antiemetics
C hoose from (a) glutamate, (b) GABA, (c) opioids, (d) monoamine (dopamine, norepinephrine, serotonin) as major contributor to –
1. general anesthesia
2. pain tolerance during surgery 3. pain perception 4. behavioral changes associated with pain 5. addiction 6. emesis (for early treatment of
General anesthesia - B
pain tolerance during surgery - B
Pain perception - A
Behavioral changes - C
Additiction = C
Emesis -
Antiemetics - D
