Sedatives and Hypnotics Flashcards
alpha beta receptor
endogenous agonist: GABA
exogenous agonist: Muscimol
competitive antagonist: Bicucilline
Alpha Gamma receptor
agonist: benzodiapene
competitive antagonist: Flumazenil
Inverse agonist: beta carboline
blocks cloride pore
picrotoxin
ultrashort acting barbiturates
highly lipid soluble - redistribution into fats
- Thiopentone/Na pentothal - general anaesthetic - inducing agent, narcoanalysis, reduces oxygen demand and is cerbro/cardio protective
Thiopentone mixed in sodium bicarbonate
never give intraarterial - Methohexitone/Methohexital
reduces seizure threshold - DOC for ECT in psychiatric disorders, major depression, catatonia
ECT
DOC: Methexitone
other barbiturates like Thiopentane
Propofol (most common)
Ketamine: preferred in depression
Short acting barbiturates
Butabarbitone, Amobarbitone, Pentobarbitone, Secobarbitone
iv drug to produce sedation or anesthesia
Long acting barbiturates
- Primidone - oral - essential tremors (propranolol and primidone), epilepsy
primidone (active drug) converted into phenobarbitone (active drugs) - Phenobarbitone -
oral and iv
metabolised by CYP3A4 + glucuronide conjugation (75%) + rest 25% unchanged, excreted
DOC for neonatal seizure and neonatal jaundice
Criggler Najar type 2, Gilbert syndrome
SE: paradoxical excitation in children (idiosyncratic - suppression of inhibitory neurons) : increased seizures, hyperkinesia, increased pain
essential tremors
Propranolol and Primidone
clinical features of porphyria
pallor
photosensitivity
craving for blood
abdominal pain, vomiting
drugs contraindicated in porphyria
Sulfonamides
Estrogens
Valproate
Ergotamine
Rifampicin
Erythromycin
Phenytoin
OCP
Barbiturates
Alcohol
barbiturate poisoning clinical features
unconscious/ comatose and flabby
hypotension and cardiovascular collapse
renal shut down
pulmonary complications
bulbous eruption on skin
respiratory depression
treatment of barbiturate poisoning
urea + malonioc acid = barbiturates
- gastric lavage using activated charcoal
- supportive measures such as maintenance of blood volume by fluid infusion and use of vasopressors- dopamine may be preferred
- forced alkaline diuresis using NaHCO3
4.. hemodialysis and hemoperfusion - analeptics - Doxapram and Bemegride
- picrotoxin is effective
Analeptics for barbiturates poisoning
Doxapram, Bemegride
BZDs in antiseizures
Diazepam
Lorazepam
Clonazepam
Clobazam
Midazolam
iv Diazepam/Lorazepam - used to control life threatening seizures in status epilepticus (DOC - iv Lorazepam), tetanus, drug induced convulsions, febrile convulsions (Doc - rectal Diazepam; intranasal Midazolam also used)
Clonazepam - absence seizures
BZDs in antianxiety
Diazepam
Clonazepam
Oxazepam
Lorazepam
Alprazolam
Chlordiazepoxide
Anxiety
performance anxiety - Propranolol
anxiety disorder / neurosis - SSRi
acute anxiety attack - BZD
BZDs as preanesthetic
Diazepam
Lorazepam
Midazolam
Remimazolam
sedation, anxiolytic, anterograde amnesia
BZDs in insomnia (insomnia and daylight anxiety)
Flurazepam
Triazolam
Estazolam
Quazepam
Temazepam
Hypnosis-
Diazepam
Flurazepam
Nitrazepam
Alprazolam
Lorazepam
Triazolam
BZDs as muscle relaxants and miscellaneous
muscle relaxants - all ( Diazepam is a GABA-A agonist and Baclofen (non sedative, non addictive muscle relaxant)is GABA-B agonist)
Delirium tremens - iv Diazepam
Anticipatory vomiting - Lorazepam
Date rape drugs
Alcohol (most commonly misused)
Flunitrazepam (Rohypnol) - colourless and tasteless BZD, now banned
Ketamine
Barbiturates and BZDs
Gamma hydroxy butyrate
Class B metabolism of BZDs
no CYP3A4 metabolism, inly glucuronide conjugation
Triazolam
Oxazepam
Temazepam
Estazolam
Lorazepam
Longest acting BZD
Flurazepam
Shortest acting BZD
Remimazolam
Midazolam
Max plasma protein bound BZD
Diazepam
