Opiods, Antiepileptics, Anaesthetics Flashcards
What are some examples of opioid drugs?
Morphine, fentanyl, codeine, heroin, methadone, meperidine, dextromethorphan, diphenoxylate
Mechanism of opioids?
Agonists at opioid receptors to modulate synaptic transmission.
What drugs correspond to the following receptors?
mu
delta
kappa
mu = morphine delta = enkephalin kappa = dynorphin
What channels do opiods act on?
open K+ channels, close Ca2+ channels
Which NTs are prevented from release by opioid activity?
ACh, NE, 5-HT, glutamate, substance P
Which opioid is indicated for cough suppression?
dextromethorphan
Which opioids are indicated for diarrhea?
loperamide and diphenoxylate
What analgesic class can be used to treat acute pulmonary edema?
opioids
What are two toxicities of opiods that patients do not develop tolerance to?
miosis and constipation
How can you treat toxicity of opioids?
opioid receptor antagonists: naloxone or naltrexone
What drug is a partial agonist of mu and kappa- receptors?
Butorphanol
What is the advantage of using Butorphanol over other opioids?
It causes less respiratory depression than full agonists
What are two toxicities of Butorphanol?
- Because it’s a partial agonist, it can cause withdrawal if giving concomitantly with full agonists
- Overdose not easily reversed with nalaxone
What is tramadol?
A very weak opioid agonist; it also inhibits serotonin and NE reuptake – “tram it all” with tramadol)
What is butorphanol indicated for?
Severe pain such as migraines and labor
What is tramadol indicated for?
chronic pain
What are toxicities of tramadol?
- similar to opiods
- decreases seizure threshold
- serotonin syndrome
What is the mechanism of Ethosuximide?
Blocks thalamic T-type Ca2+ channels
What are the side effects of Ethosuximide?
EFGHIJ: Ethosuximide causes fatigue, GI distress, Headache, Itching (urticaria), and Stevens-Johnson syndrome
What is ethosuximide used for?
absence seizures
What kind of seizures are benzodiazapenes used for?
- Status epilipticus
2. Eclampsia seizures (1st line is MgSO4)
What is the mechanism of benzos?
Increases GABA(a) action
What are side effects of benzos?
Sedation, tolerance, dependence, respiratory depression
What are three indications for phenytoin?
- Partial seizures (simple and complex)
- tonic clonic (1st line)
- status epilepticus prevention
Side effects of phenytoin:
Eyes: nastagmus, diplopia
Mouth: gingival hyperplasia
Nerves: ataxia, sedation, peripheral neuropathy
Metabolic: induction of P450
Blood: megaloblastic anemia (inhibits intestinal conjugase);
Lymph: lymphadenopathy
Bone: osteopenia
Skin: Stevens Johnson Syndrome
Developmental: fetal hydantoin syndrome (teratogenesis)
What are the indications for carbamazepine?
1st line for partial (simple and complex) and tonic-clonic
What is the mechanism of action of carbamazepine?
Na+ channel inactivation
Side effects of carbamazepine:
Eyes: diplopia
Nerves: ataxia
Metabolic: induction of P450, liver toxicity
Blood: dyscrasias (agranulocytosis, aplastic anemia)
Skin: Stevens-Johnson
Development: Teratogenesis
What is the mechanism of action of Valproic acid?
Na+ channel inactivation, increased GABA concentration by inhibiting GABA transaminase
What are some toxicities of Valproic acid?
GI, distress, fatal hepatotoxicity (rare, measure LFTs), neural tube defects (spina bifida), tremor, weight gain, contraindicated in pregnancy
What is valproic acid for?
all seizures except status epilepticus, myoclonic seizures, bipolar disorder
What three drugs are used primarily for partial seizures?
Gabapentin, Tiaginbine, Vigabatrin
Primary side effects of gabapentin?
Sedation, ataxia
Mechanism of gabapentin?
high voltage-activated Ca2+ channels despite designation as GABA analog
What drug can be used for migraine prophylaxis?
gabapentin
Which antiepileptics can be used for bipolar d/o?
Valproic acid and gabapentin
Which antiseizure drug is marketed for postherpetic neuralgia?
gabapentin
Which antiseizure drug is marketed as first line for trigeminal neuralgia?
carbamazapine
Phenobarbital mechanism and indications
Increases GABA(a) (like phenytoin) and is used to treat partial and tonic-clonic seizures
What are the mechanism and indications for topiramate?
Blacks Na+ channels, increases GABA action
Indicated for partial and tonic-clonic
Indications and mechanism for lamotrigine
partial, tonic clonic; blocks voltage-gated Na+ channels
Toxicity of lamotrigine
Stephens-Johnson (must be titrated slowly)
Mechanism and indications for levetiracetam
unknown (may modulate GABA and Glu release); partial and TC
Indications and mechanisms for Tiagabine and Vigabatrin
both indicated for partial seizures; increase GABA by inhibiting uptake (Tiagabine) and transaminase (Vigabatrin)
What are some barbituates?
Phenobarbital, penorbital, thiopental, secorbarbital
What do barbituates work?
Facilitate GABAa action by increasing duration of Cl- channel opening–> decrease neuron firing
Clinical uses for barbituates
sedative for: anxiety, seizures, insomnia, induction of anesthesia
What drug is used as a sedative for induction of anesthesia? What class of drug is this?
Thiopental; barbituate
Toxicities of barbituates
Respiratory and cardiovascular depression (can be fatal)
CNS depression (can be exacerbated by EtOH use)
Dependence
Drug interactions (induces P450)
How do you treat a barbituate overdose?
Supportive: assist respiration and maintain BP
What are some examples of Benzodiazepines?
Diazepam, lorazempam, triazolam, temazepam, oxazepam, midazolam, chlordiazepoxide, alprazolam
