Benzodiazepines Flashcards
What are common indications for benzodiazepines?
- Seizure and status epilepticus
- Alcohol withdrawal reactions
- Sedation for interventional procedure
- Anxiety
- Insomnia
What is the mechanism of action of benzodiazepines?
Benzodiazepines facilitate and enhance binding of GABA to GABAa receptor. This has a widespread depressant effect on synaptic transmission, resulting in reduced anxiety, sleepiness, sedation and anticonvulsive effects
Why are benzodiazepines used in alcohol withdrawal?
Ethanol (‘alcohol’) also acts on the GABAA receptor, and in chronic excessive use the patient becomes tolerant to its presence. Abrupt cessation then provokes the excitatory state of alcohol withdrawal. This can be treated by introducing a benzodiazepine, which can then be withdrawn in a gradual and more controlled way
What are important side effects of benzodiazepines?
- Sedation
- Drowsiness
- Coma
- Cardiorespiratory depression
- DEpendence
- Withdrawal
- Amnesia
- Paradoxical excitability
- Increased appetite
When are benzodiazepines best avoided?
- Respiratory Impairment
- Neuromuscular disease
- Liver disease
What would you prescribe someone if they had liver failure but were going through alcohol withdrawal?
Lorazepam - depends less on the liver for its elimination
What is the function of GABAa receptors?
Chloride channel that opens in response to binding of GABA. Flow of sodium into cell causes hyperpolarisation
What is the antidote to benzodiazepine overdose?
Flumazenil
Why shoudl flumazenil no be given to reverse benzodiazepine-induced sedation when it is part of a mixed/uncertain overdose?
May precipitate seizures, which will subsequently be difficult to treat due to blockade of GABA receptors
What are examples of benzodiazepines?
- Lorazepam
- Midazolam
- Temazepam
- Chlordiazepoxide
What is the duration of action of Midazolam?
Short
What are the long acting benzodiazepines?
- Lorazepam
- Diazepam
- Chlordiazepoxide
What are features of benzodiazepine overdose?
- CNS depression: lethargy, somnolence, hyporeflexia
- Respiratory depression
- Mild hypotension
- Ataxia
- Slurred speech
What are indications for flumazenil use?
- Severe respiratory depression
- Overdose in benzodiazepine-naive patients (e.g., accidental ingestion in children, periprocedural oversedation with benzodiazepines)
What are features of benzodiazepine withdrawal?
- Autonomic nervous system - Sweating, Nausea, vomiting, and anorexia, Hypertension
- Neurological - Seizure, Tremors, Memory impairment
- Psychiatric - Withdrawal psychosis with optic and auditory hallucinations, Depressive moods
