9. Anxiolytic and Hypnotic Drugs Flashcards
What are the key types of anxiolytic and hypnotic drugs?
Benzodiazepines, barbiturates.
What is the naming rule of benzodiazepines? Name 3 examples.
Normally ends in -lam or -pam. Diazepam, lorazepam, temazepam.
Name the benzodiazepine antagonist drug.
Flumazenil.
What is the naming rule of barbiturates? Name 2 examples.
Ends in -barbital. Phenobarbital, amobarbital, pentobarbital.
What is the mechanism of action of benzodiazepines?
Modulate GABA effects (allow Cl- through pore for hyperpolarisation and decreased neurotransmission from neurone) to increase them.
What are the actions of benzodiazepines?
Reduce anxiety, sedative/hypnotic, anterograde amnesia, anticonvulsant, muscle relaxant.
How are benzodiazepines anxiolytic?
Selectively enhance GABAergic transmission to inhibit neuronal circuits in limbic system of the brain.
How can benzodiazepines cause muscle relaxation?
High doses - increase presynaptic inhibition in spinal cord.
What are the therapeutic uses of benzodiazepines?
Severe anxiety, sleep disorders, amnesia, seizures, muscular disorders.
Are benzodiazepines lipophilic and/or hydrophilic? What is the implication of this on absorption?
Lipophilic. Means they’re rapidly and completely absorbed after oral administration.
How are most benzodiazepines metabolised?
Hepatic system metabolises them, excreted in urine.
What is a risk of long term benzodiazepine use? What reduces the harm of this?
Dependence. Doses should be stopped very gradually.
What are the common side effects of benzodiazepines?
Drowsiness and confusion. Ataxia at high doses. Cognitive impairment.
What is the mechanism of action of barbiturates?
Sedative-hypnotic action by enhancing GABAergic transmission and prolonging the duration of chloride channel openings. Also block excitatory glutamate receptors.
What are the adverse actions of barbiturates?
Depression of CNS - sedation at low doses, hypnosis-anaesthesia-coma-death at high doses; respiratory depression.
What are the therapeutic actions of barbiturates?
Anaethesia, anticonvulsant, sedative/hypnotic.
How are barbiturates metabolised and excreted?
Metabolised by liver, excreted in urine.
What are the adverse effects of barbiturates?
Drowsiness, impaired concentration, P450 enzyme induction, tremor, nausea, potential for addiction.
What are the withdrawal effects of barbiturates?
Tremors, anxiety, weakness, restlessness, nausea, vomiting, seizures, delirium, cardiac arrest.
What are the therapeutic advantages of benzodiazepine use?
Potential use in chronic therapy for seizures, less potent and slowly eliminated so no rebound insomnia on discontinuation, agent of choice for panic disorders, fewer drug interactions as no phase I metabolism and can be used in patients with hepatic impairment.
What are the therapeutic disadvantages of benzodiazepine use?
May disturb intellectual functioning and motor dexterity, potential for dependence and withdrawal seizures.
