Pharmacology of Anxiolytics Flashcards
What drugs are used to treat anxiety?
Barbiturates (not recommended) Benzodiazepines Antidepressant drugs Buspirone Pregabalin β-blockers (propanolol)
What are some examples of benzodiazepines?
Midazolam
Lorazepam
Temazepam
Diazepam
What are the pharmacological effects of benzos?
Reduce anxiety and aggression Hypnosis/sedation Muscle relaxation Anticonvulsant effect Anterograde amnesia
How do benzos act?
All act by increasing GABA-mediated inhibition
What is the choice of benzo determined by?
Duration of action
Describe Gamma amino butyric acid (GABA)
The main inhibitory transmitter in the brain
Widespread distribution
Causes hyperpolarisation of target cells
Where is glycine found?
Spinal cord and brain stem
What are the clinical uses of benzos?
Acute treatment of extreme anxiety Hypnosis Alcohol withdrawal Mania Delirium Rapid tranquillisation Premedication before surgery or during minor procedures Status epilepticus
What are the problems with benzos?
Usually safe in overdose
Paradoxial aggression
Anterograde amnesia and impaired coordination (Rohypnol)
Do cause tolerance and dependence
What causes withdrawal symptoms?
Neuroadaptation of the GABA response- chronic treatment causes decreased response to GABA. Withdrawal results in anxiety/conculsions possibly due to decreased density of BZ receptors
What withdrawal symptoms can occur after stopping benzos?
Confusion Toxic Psychosis Convulsions Insomnia Anxiety Loss of appetite and weight Tremor Perspiration Tinnitus Perceptual disturbances
How should you withdraw benzos?
Transfer patient to equivalent daily dose of diazepam/chlordiazepoxide- preferably taken at night
Reduce dose every 2-3 weeks in steps of 2/2.5mg: if withdrawal symptoms occur, maintain dose until symptoms improve
Reduce further, if necessary in smaller steps, better to reduce too slowly than quickly
Stop completely: can take 4 weeks to more than a year
When should beta blockers be used?
For somatic anxiety symptoms e.g. palpitation, tremor
When should pregabalin be considered in anxiety?
When patient is not responsive to other treatments
What is pregabalin?
Anxiolytic- CCB/ GABA enhancer
