Pharmacology Flashcards
What are CNS Stimulants
Increase CNS activity
Lead to heightened alertness and stress
Often mimic or increase the action of excitatory neurotransmitters
Examples of CNS stimulants
Amphetamines
Caffeine
What is neurotransmitter modulation?
When CNS drugs directly affect neurotransmitter levels or receptor activity
Reflexly acting drugs
They influence the CNS indirectly through peripheral actions, like nicotine
List of neurotransmitters in the CNS
- Amino Acids
- Monoamines
- Peptides
- Nitric oxide
- Endocannabinoids
- Histamine
- Tachykinins
Examples of Amino Acids
Ach, GABA, Glutamate, Glycine
Examples of monoamines
NE, Dopamine, Serotonin
What are antidepressants
Medications that increase levels of certain neurotransmitters in the brain to improve mood.
Modulate neurotransmitter systems without slowing down overall CNS activity
Notably serotonin and norepinephrine
Examples of peptides
Opioid peptides, Neurotensin, Substance P, Somatostatin, Neuropeptide Y
Examples of antidepressants
SSRIs, like prozac,
SNRIs are serotonin and norepinephrine reuptake inhibitors
TCA are also reuptake inhibitors
MAOIs
Depressants and their uses
Drugs that lower neurotransmission levels and decrease electrical activity in the brain, reducing arousal or stimulation.
Used for anxiety, insomnia, seizures and as muscle relaxants
Examples of CNS depressants
Alcohol
Benzodiazepines
Barbiturates
Opioids
What are CNS stimulants?
Increase activity, speeding up mental and physical processes.
Work by increasing levels of neurotransmitters like dopamine and norepinephrine
Used to treat ADHD, narcolepsy and sometimes depression
Examples of CNS stimulants
Caffeine, nicotine, cocaine, methamphetamine, MDMA
Classes of CNS depressants
- Sedatives
- Hypnotics - depress CNS to sleep
- Narcotics - cause sleep and pain relief
- GAs - cause period of unconsciousness
Sedatives
Anxiolytic drugs that reduce anxiety excitement, nervousness etc.
This involves mild depression of CNS, but not enough to cause sleep or much effect on motor or mental functions.
Concentration dependent
Classification of sedatives/hypnotics
Benzodiazepines
Barbiturates
Newer agents
Tranquilizers
Produce calmness and quietness
Reduce anxiety, tension and aggression
Anticonvulsant drugs
Used to treat epileptic seizures
Convulsion is caused by depolarization of the nerve
So to return to normal state need to repolarize
Method of action of anticonvulsant/antiepileptic drugs
Blocking of Na+ channels
Enhance GABA mediated synaptic inhibition
Ca2+ channel blockade (block)
Analgesics
Relieve pain without impairing consciousness
Narcotics can be natural like morphine and codeine or synthetic, but may cause addiction
Non-narcotics are NSAIDs or salicylates, like paracetamol
Affects of opioids
- Analgesia
- Respiratory depression
- Waste retention
- Cough suppression
- Sedation
- Euphoria/dysphoria
Method of action of opioids
Stimulation of µ, δ, κ opioid receptors
Increase K+ efflux and reduce Ca2+ influx
Decreased cAMP
More polarized, so less firing
Elimination of pain
Progressive grade of CNS excitation
Mild hyper-excitability
Severe hyper-excitability
Mild convulsion
Severe convulsion
What kind of stimulants act directly on the CNS?
Cortical stimulants
Medullary stimulants
Spinal stimulants
Sympathetic Nervous System
Preganglion nerve connects CNS to ganglia
Fight or flight
Parasympathetic Nervous System
Postsynaptic nerve connects ganglia to organs
Rest and digest
Ganglia
Contains nerve endings of pre-G and nerve fibres and cell bodies of post-G nerve fibres
Properties of neurotransmitters of sympathetic nerves
Adrenergic
NE
Post G
Neurotransmitters of parasympathetic nerves
Cholinergic
Ach
Post G
Types of cholinergic or choline agonists
Direct acting
Indirect acting
* Irreversible AChE agents
* Reversible AChE agents
Types of Anticholinergic/Parasympatholytic drugs
Nonselective muscarinic receptor antagonists
Selective muscarinic antagonists
Uses of Anticholinergic drugs
As spasmolytic (relieves spasms)
Treat hypermotility of GIT (too much activity in digestion)
Treat hypertonicity (too much solute) of uterus, UB, ureter, bronchioles
Action of α1 receptor
- Vasoconstriction of blood vessels
- Increased blood pressure
- Decreased GI motility
- Contracts UB sphincter
- Dilates pupil
- Contracts uterus
Action of α2 receptor
- Inhibits release of NE
- Decreases blood pressure
- Decreases intestinal secretion
Action of β1 receptors
- Increases heart rate
- Forces contraction of the heart
- Cardiac stimulant
Action of β2 receptors
- Relaxation of smooth muscle in the bronchi
- Bronchodilator
- Relaxation of smooth muscle in uterus
- Relaxation of smooth muscle in peripheral blood vessels
_ receptors seem to increase sympathetic traits and _ receptors tend to decrease them
1 and 2
Uses for adrenergic drugs
Adrenaline can be used to treat cardiac arrest or anaphylaxis
Heart block - isoprotenerol
Cardiogenic shock
Adverse effects of anti-adrenergic drugs
Hypertension
Bradycardia
Edema
Indications of anti-adrenergic drugs
Hypertension
Visceral ischemia
Angia pectoris
Myocardial infarction
Cardiac dysrhythmia
Classification of antiadrenergic drugs
Adrenergic neuron blockers (e.g. Methyldopa, Reserpine)
Adrenergic receptor blockers (α & β antagonists)
Adrenergic drugs classification
Direct acting α or β agonists (can be selective or non selective)
Indirect acting (Amphetamines)
Mixed acting (Ephrdrine)
