Sedatives anxiolytics Flashcards
Barbituants
- narrow therapeutic index
- Obsolete as anxiolytics
- Still used as IV induction agents
- Anti convulsants
Properties of benzodiazepines
- Highly lipophilic
- Well absorbed orally
- Highly protein bound
- Hepatic metabolism
- Active metabolites
What are Benzodiazepines excreted as?
Gluconoride conjugate
What are the major effects of benzodiazepines?
- Anxiolytic: reduce anxiety
- Hypnotic: induce sleep
- Reduce muscle tone
- Anterograde amnesia (pros and cons)
- Anticonvulsant effects
Administration of benzodiazepines
- Normally given orally or intravenously
- Can be given by intranasal or rectal route
- Not advised to be given intramuscular route
Describe the structure of GABA a receptors
- Pentameric arrangement
- Central ion channel pore
- 18 possible subunits
- Approx 30 forms of receptor
What allosterically activates the GABA a receptor
- Anaesthetics
* Benzodiazepines
What is flumazenil
Competitive bezodiazipine antagonist
What are the side effects of flumazenil?
- nausea
- Vomiting
- may precipitate agitation and seizures
How is flumazenil given?
IV in 100microgram increments
What are Z drugs?
- Act via benzodiazepine receptors
- Zopiclone
- Zalepam
- Zolpidem
What is tolerance?
Physiological state characterised by a decrease in the effects of a drug with chronic administration
Describe the tolerance of benzodiazepines
- Tolerance develops quickly for sedative effects
* More slowly for anxiolytic and anticonvulsant effects
What is the mechanism for tolerance?
- Neuro adaptive process
- Desensitisation of inhibitory GABA receptors
- Sensitisation of (excitatory) NMDA receptors
- Adaptions take place on different time scale
Describe dependence
- Drug induces a rewarding experience
- Drug taking becomes compulsive
- Psychological dependence
- Physical dependence
- Genetic factors