Anxiolytics Flashcards
Fear
Fear is a response to imminent, clear and present danger or threat.
Anxiety
Anxiety is a response to anticipated threat, which may be vague and ill-defined.
what are fear and anxiety
For both fear and anxiety, the threat may be real or perceived.
For both fear and anxiety, the response include defensive behaviors, autonomic reflexes, arousal, corticosteroid production, and negative emotions.
Under normal emotion: aroused, efficient, “fight or flight”.
For a psychiatric state: interferes with activities of daily living, work and relationships
- psychiatric state = ill-defined and chronic
Manifestation of anxiety states
• Psychological components: – Negative emotions: Worry, nervousness, unease. – Arousal. (continuously alert) – Lack of concentration. – Insomnia.
• Physical symptoms: – Tachycardia. – Shortness of breath. – Nausea. – Gastric acid hypersecretion. (ulcer) – Trembling.
Biochemical basis of anxiety
- Central and peripheral noradrenergic / adrenergic activation —> the “Flight or Fight” response
- Stress response —> Hypothalamus-pituitary-adrenal (HPA) axis —> secretion of stress hormones (cortisol).
Types of Anxiety disorders
• Generalized anxiety disorder (GAD):
– Excessive,uncontrollable worry over everyday matters.
– Interferes with daily functioning.
– Has both psychological and physical symptoms.
– Diagnosed when present for at least 6 months.
– Most common cause of disability in the workplace.
• Other anxiety and fear disorders: – Post-traumatic stress disorders (PTSD). – Phobias. – Panic disorder. – Obsessive compulsive disorders (OCD).
Anxiety disorders: therapeutic rationale
• CNS depressant:
– Sedative –> causes sedation, relaxation.
– Hypnotic –> induces drowsiness and sleep, may have amnestic effects.
– Anxiolytic –> reduces anxiety.
Note: These actions are closely-related. The same drug can have more than one action depending on dose.
Eg:
– Low dose –> anxiolytic and sedative effects
– Higher doses –> hypnotic
– Even higher doses –> can cause anesthesia, used for surgery
Strength of CNS depression
1) Hypnotic
2) Sedative
3) Anxiolytic
Benzodiazepines
– Used as anxiolytics / sedatives: eg, diazepam, lorazepam, alprazolam.
– Used as hypnotics: eg, diazepam, triazolam, temazepam.
– Used as pre-anaesthetics: eg, diazepam, midazolam.
– May also have anti-convulsant effects: eg, diazepam, clonazepam
Benzodiazepines Used as anxiolytics / sedatives:
– Used as anxiolytics / sedatives: eg, diazepam, lorazepam, alprazolam.
Benzodiazepines – Used as hypnotics:
Used as hypnotics: eg, diazepam, triazolam, temazepam.
Benzodiazepines – Used as pre-anaesthetics:
– Used as pre-anaesthetics: eg, diazepam, midazolam
Benzodiazepines – May also have anti-convulsant effects:
– May also have anti-convulsant effects: eg, diazepam, clonazepam
Benzodiazepines MOA
Binds to +ve allosteric site of GABA receptor and potentiate the effect of GABA actions by increasing the frequency of GABA-induced channel opening.
GABA—inhibitory transmitter in brain regions: acts via GABAA receptors Cl-channels. It causes the CL ions channel to open, leading to hyperpolarization of the cell.
BZD potentiates influx of CL ions leading to hyperpolarization, making cell more difficult to depolarize and therefore reduces neural excitability.
therefore neurons not firing.
Eg:
- limbic system (alter mood)
- Reticular activating system (causes drowsiness)
- Motor cortex (relax muscles)
Short acting BZD
1) Midazolam (Anxiety. induction of general anesthesia, procedural sedation)
2) Triazolam (insomnia)
Midazolam
Short acting BZD
1) Midazolam (Anxiety. induction of general anesthesia, procedural sedation)
