Sedatives and hypnotics Flashcards
What is the definition of anxiolytics, sedatives, and hypnotics?
• Anxiolytics: Relief anxiety with less sedation.
• Sedatives: Reduce agitation, motor activity, and cognitive function.
• Hypnotics: Induce sleep and are used in insomnia.
What is the mechanism of action of Benzodiazepines?
Benzodiazepines bind to receptors (BNZsR), potentiate the action of GABA (the major inhibitory neurotransmitter in the central nervous system), increase the frequency of opening of chloride ion channels, enhance the entrance of chloride ions inside the cell, leading to hyperpolarization of the neuron and reduced action potential in the nerve cell.
What are the clinical uses of Benzodiazepines?
- Anxiety disorders: Generalized anxiety disorder, panic attacks, and phobia.
- Sleep disorders (hypnotic): Temazepam reduces latency to sleep and increases sleeping time.
- Seizures: Lorazepam and diazepam are used in emergencies.
- Muscular disorders: Treatment of skeletal muscle spasms and spasticity.
- Amnesia: In short-term procedures such as endoscopes.
What are the adverse effects of Benzodiazepines?
- Daytime sedation, fatigue, drowsiness (hangover effect).
- Ataxia and motor incoordination.
- Cognitive impairment.
- Respiratory and CNS depression at high doses if coadministered with opioids or alcohol.
- Tolerance and dependence.
What is the treatment for Benzodiazepine overdose?
Flumazenil is a selective competitive antagonist that acts at BNZs receptors, can reverse the effects of benzodiazepines, and is given intravenously.
What are the clinical uses of Barbiturates?
- Epilepsy: In tonic-clonic epilepsy (oral phenobarbitone).
- Induction of anesthesia: I.V thiopentone.
- Neonatal jaundice: As enzyme inducers.
What are the adverse effects of Barbiturates?
- Drowsiness, dizziness, confusion, coma, and death.
- Respiratory depression, especially in patients with asthma and bronchitis.
- Hypotension, reduced cardiac output, and myocardial depression.
- Physical and psychological dependence with withdrawal symptoms.
- Drug interactions; potentiate the effect of other CNS depressants and induce metabolism of other drugs.
What is the mechanism of action of Buspirone?
Buspirone acts as a partial agonist at the serotonin 5HT receptors, relieving anxiety with less sedative, hypnotic, or CNS depressive effect and less cognitive impairment.
What are the effects of Nonbenzodiazepine hypnotic drugs (Z-drugs)?
Zolpidem and Zaleplon act like benzodiazepines on benzodiazepines/GABA receptors but have different chemical structures. They have similar effects to benzodiazepines but cause less dependence and fewer withdrawal symptoms.
What is the role of Melatonin in sleep?
Melatonin maintains the circadian rhythm in the normal sleep-wake cycle and reduces latency to sleep.
What are the withdrawal symptoms of Benzodiazepines?
Withdrawal symptoms include anxiety, insomnia, confusion, and convulsions. Gradual withdrawal by tapering is recommended, and symptoms are more severe with short-acting benzodiazepines.
What is the difference between short-acting, intermediate-acting, and long-acting Benzodiazepines?
• Short-acting: Alprazolam, midazolam (less prone to accumulation or drug interactions).
• Intermediate-acting: Diazepam.
• Long-acting: Chlordiazepoxide (have pharmacologically active metabolites).
What is the dose-response relationship for Barbiturates and Benzodiazepines?
• Barbiturates: Can cause coma, medullary depression, and anesthesia at increasing doses.
• Benzodiazepines: Cause hypnosis, sedation, and anxiolysis at increasing doses.
