opioid analgesics / Benzodiazepines / Barbiturates / Nonbenzodiazepine hypnotics Flashcards
opioid analgesics - drugs
- Morphine 2. fentanyl 3. codeine
- lorepamide 5. methadone
- meperidine 7. dextromethorphan
- diphenoxylate 9. pentazocine
opioid receptors
μ=morphine, δ=enkephalin, κ=dynorphin
opioid analgesics - mechanism of action
act as agonists at opioid receptors to modulate synaptic transmission –> open K+ channels, close Ca2+ channels –> decrease synaptic transmission. Inhibit release of Ach, norepinephrine, 5-HT, glutamate, substance P
opioid analgesics - Inhibit release of
Ach, norepinephrine, 5-HT, glutamate, substance P
opioid analgesics - clinical use (and which drugs, if specific)
- pain controle 2. cough suppressor (dextromethorphan)
- diarrhea (loperamide, diphenoxylate)
- acute pulmonary edema
- maintenance programs for heroin addicts (methadone, buprenorphine + naloxone)
maintenance programs for heroin addicts - drugs
methadone, buprenorphine + naloxone
opioid analgesics - toxicity
- addiction
- respiratory depression
- constipation (no tolerance)
- miosis (pinpoint pupils) (no tolerance) (except meperidine –> mydriasis)
- addictive CNS depression with other drugs
- opioid withdrawal syndrome
- suppressed gag reflex
opioid analgesics - toxicity - tolerance does not develop to
miosis and constipation
opioid analgesics toxicity treated with
opioid receptor antagonists (naloxone or natrexone)
buprenorphine - mechanism of action
- agonistic effects at μ δ opioid receptors
- antagonist effect at κ opioid receptors
butorphanol - mechanism of action
- κ-opioid receptor agonist
- μ-opioid receptor partial agonist
butorphanol - clinical use
severe pain (migraine, labor)
butorphanol vs full opioids agonists according to side effects
butorphenol causes less respiratory depression than full opioid agonists
butorphanol - toxicity
- can cause opioid withdrawal symptoms if patient is also taking full opiod agoinsts (competition for opioid receptor)
- overdose not easily reversed with naloxone
- less respiratory depression than full opioid agonists
butorphenol - antidote
overdose not easily reversed with naloxone
tramadol - mechanism of action
very weak opioid agonist
also inhibits 5-HT and norepinephrine reuptake
tramadol - clinical use
chronic pain
tramadol toxicity
- similar to opioid
- decreases seizure threshold
- serotonin syndrome
dextromethorphan + seretonergic agents –>
seretonin syndrome
barbiturates - drugs
(-BARBITAL + THIOPENTAL)
- phenobarbital
- pentobarbital
- secobarbital
- thiopental
barbiturates - mechanism of action
facilitate GABA A by increase DURATION of Cl- channel opening, thus decrease neuron firing
barbiturates - contraindicated during
- porphyria 2. pregnancy
- liver disease 4. alcohol
- benzodiazepines
- CNS depression
barbiturates - clinical use
sedative for ANXIETY, SEIZURES, INSOMNIA
induction of anesthesia (thiopental)
barbiturates - induction of anesthesia - drugs?
thiopental
barbiturates - toxicity
- respiratory and cardiovascular depression (can be fatal)
- CNS depression (can be exacerbated by alcohol use)
- dependence
- induces of P-450
- withdrawal syndrome
- teratogen
barbiturates - overdose treatment
- mechanical respiration
- hemodialysis
- urine alkalinization
- maintain BP
benzodiazepines - drugs
- diazepam 2. lorazepam 3. triazolam 4. oxazepam
5. midazolam 6. chlordiazepoxide 7. alprazolam 8. Temazepam
benzodiazepines - mechanism
facilitate GABA - A action by increase FREQUENCY of CL- channel opening
Most benzodiazepines have … half lives and … metabolites
long
active
(NOT THOSE WITH SHORT HALF LIVES)
benzodiazepines with short half lives
- alprazolam
- Triazolam
- oxazepam
- Midazolam
benzodiazepines with short half lives - characteristic
higher addictive potential
substances that bind GABA-A receptor (ligant-gated Cl- channel)
- benzodiazepines
- barbiturates
- alcohol
benzodiazepines - clinical use
- anxiety
- spasticity
- status epilepticus (lorazepam, diazepam)
- hypnotic (insmonia)
- general anesthetics (amnesia, muscle relaxation)
- night terrors
- sleepwalking
- detoxification (especially alcohol withdrawal - delirium tremens)
- ECLAMPSIA
benzodiazepines - side effects
- dependence
- addictive CNS depression effects with alcohol
- respiratory deppresion less and coma (less risk that barbiturates)
benzodiazepines vs barbiturates according side effects
benzodiazepines have less respiratory deppresion less and coma risk
benzodiazepines - overdose treatment
flumazenil (comptetitive antagonist at GABA benzodiazepine receptor)
flumazenil - mechanism of action and clinical use / side effects
- comptetitive antagonist at GABA benzodiazepine receptor
- treat benzodiazepines overdose
- can precipitate seizures by causing acute benzodiazepine withdrawal
Nonbenzodiazepine hypnotics - drugs
- Zolpidem
- Zaleplon
- Eszopiclone
Nonbenzodiazepine hypnotics - mechanism of action
act via the BZ1 subtype of the GABA receptor
Nonbenzodiazepine hypnotics - reverse by
flumazenil
Nonbenzodiazepine hypnotics - clinical use
insomnia
benzodiazepines - useful as general anesthetics because
- amnesia
2. muscle relaxation
Nonbenzodiazepine hypnotics - side effects
- ataxia 2. headaches 3. confusion
- dependency (less risk than benzodiazepines)
- modest day-after psychomotor depression and few amnestic effects
- short because of rapid metabolism by liver enzyme
Nonbenzodiazepine hypnotics vs benzodiazepines according side effects
- Nonbenzodiazepine hypnotics have less risk than benzodiazepines for dependency
- sleep cycle is less affected
Nonbenzodiazepine hypnotics - duration (why)
short because of rapid metabolism by liver enzyme
Nonbenzodiazepine hypnotics vs older sedative hypnotics
Nonbenzodiazepine hypnotics cause only modest day-after psychomotor depression and few amnestic effects
overdose treatment of 1. opioids 2. benzodiazepines 3. barbiturates
- opioids –> naloxone, naltrexone
- benzodiazepines –> flumazenil
- mechanical respiration, hemodialysis, urine alkalinizationm maintain BP
Barbiturates vs benzodiazepines according to mechanism of action on GABA - A
Barbiturates –> increase the DURATION of Cl- opening
Benzodiazepines –> increase the FREQUENCY of Cl- opening
Pentazocine - mechanism
- κ-opioid receptor agonist
- μ-opioid receptor antagonist
Pentazocine - clinical use
analgesia for moderate pain
Pentazocine - adverse effects
opioid withdrawal symptoms if patient is also taking full opioid antagonist (competition for opioid receptor)