5.1 - Central Nervous System (Anxiolytics, Antidepressants, Antipsychotics) Flashcards
What is anxiety?
Difficulty to control apprehension/worry occurring more days than not (6+ months)
Symptoms:
–> Restlessness
–> Easily fatigued
–> Difficulty concentrating
–> Irritability
–> Muscle tension
–> Sleep disturbances
What drugs are anxiolytics?
Benzodiazepines, non-benzodiazepines, buspirone
What are the sedative hypnotics?
Barbituates
What sympathetic blockers are used to treat anxiety?
Propanolol, clonidine
What are the three benzodiazepines that act on GABA-A?
Lorazepam (Ativan), Clonazepam, Diazepam
What is GABA? What receptors does it act on?
Main inhibitory NT in the brain
GABA-A
–> When stimulated, increased opening of chloride channels, making cells more negative (less excitable)
GABA-B
–> Inhibits neuronal activity
What is baclofen? What does it act on?
Stimulates GABA-B to reduce muscle spasticity
What are the sites on a GABA receptor?
GABA receptor, benzodiazepine receptor, non-benzodiazepine receptor, barbituate site
What are the clinical uses of benzodiazepines?
Sedation (before surgery)
Reduce anxiety
Muscle relaxation
What are the adverse effects of benzodiazepines?
–> Drowsiness, ataxia
–> Danger of drug accumulating in body (esp w long t1/2)
–> Dangerous when combined with alcohol
–> Can cause anterograde amnesia
–> Risk of substance use disorder and tolerance (14+ days)
–> Prolonged use may lead to withdrawal syndrome if discontinued suddenly (Insomnia, restlessness, sweating, tremors, tachycardia
What is the antidote to benzodiazepines overdose?
Flumazenil
–> Benzodiazepine receptor antagonist
–> Can trigger seizures
What is psychological (behavioural) dependence?
Emotional reliance on a drug to produce pleasure or relieve discomfort
–> State of need driven by the rewarding effects of the drug (taps into reward system)
–> Can lead to cravings and compulsive use despite harmful effects
What is physical dependence?
State of adaptation to the presence of a drug leading to the development of tolerance as well as marked withdrawal syndrome following the abrupt cessation of a drug.
What is flunitrazepam?
Rohypnol
–> 10x more potent than diazepam
–> Approved for use in Europe/South America
often slipped in drinks
What is gamma hydroxybutyrate?
Found in the brain and acts on GABA receptors
–> Often contains toxic residues leftover from their chemical synthesis
Often slipped in drinks
What happens when flunitrazepam and gamma hydroxybutyrate are mixed with alcohol?
Can cause:
–> Fainting
–> Anterograde amnesia
–> Resp depression/bradycardia/hypotension
What kind of drugs are zopiclone and zolpidem? What are they used for? What are the adverse effects?
Non Benzodiazepines
–> Anxiolytic drugs that do not share same chemical structure as benzodiazepines but act on the same receptor GABA-A
–> Used to treat insomnia without decreasing stages of restorative sleep
Fewer adverse effects affecting coordination/memory
Generally, shorter duration and onset of action benzodiazepines
What does buspirone do? What are the side effects?
Decreases the release of serotonin (5-hydroxytryptamine or 5-HT)
Less sedative, does not act quickly, fewer interaction with alcohol, and less abuse than benzodiazepines.
Side effects: dizziness and lightheadedness
What alpha-2 agonist is used to treat anxiety? What does it do for anxiety?
Clonidine
–> May reduce physical symptoms but not particularly effective at reducing anxiety at the emotional level
Which B-blocker is used to treat anxiety?
Propanolol
–> Used to treat social phobia, performance anxiety, and anxiety related to the memory of stressful events
What kind of drug is phenobarbital? What is its use?
Barbiturate
–> Sedative hypnotic
Pronounced Sedative Effect
–> Was used as IV anesthetic, also in death penalty
–> Gradual tolerance leads required dose for effect to be greater than the lethal dose
What are the adverse effects of phenobarbital?
–> Lethargy, cardiovascular and respiratory depression
–> Induction of CYP enzymes
Adrenergic anxiolytics are useful at relieving what symptoms of anxiety?
Feelings of anxiety, dilated pupils, tachycardia, tremor, and remembering on stressful events
Depression is classified as…
Depressed mood or apathy + Four of the following:
–> Psychomotor retardation or restlessless
–> Weight/appetite disturbances
–> Sleep disturbances
–> Fatigue
–> Feelings of guilt or worthlessness
–> Executive dysfunction
–> Suicidal ideation
One hypothesis about depression suggests that what kinds of NTs are low?
Amines
–> Na, Da, 5HT
What is a synonym for serotonin?
5-hydroxytryptamine
What is the process of synthesizing serotonin?
Tryptophan –> 5-hydroxytrytophan –> 5-hydroxytryptamine
What are the MAO inhibitors used to treat depression? What is the mechanism of action?
Phenelzine, pargyline
–> Irreversible inhibition of monoamine oxidase, resulting in increased release of NA, DA, 5HT in synaptic cleft
What interaction of drugs can result in malignant hyperthermia?
Meperidine + irreversible MAO inhibitor (phenelzine, pargyline)