Neurology--Pharmacology Flashcards
Epinephrine in glaucoma moa, tox
alpha-agonist, decreases humor synthesis via vasoconstriction; Tox: mydriasis–do NOT use in closed angle glaucoma
brimonidine in glaucoma moa, tox
alpha2-agonist; decrease aqueous humor synthesis; Tox: blurry vision, ocular hyperemia, foreign body sensation, ocular allergic reactions/pruritus
Timolol, betaxolol, carteolol in glaucoma
B blockers; decrease aqueous humor synthesis
Acetazolamide in glaucoma
diuretic; decrease aqueous humor synthesis via inhibiton of carbonic anhydrase
pilocarpine, carbachol in glaucoma
direct cholinomimetic; increase outflow of humor via contraction of ciliary muscle and opening of trabecular meshwork
physostigmine, echothiophate in glaucoma
indirect cholinomimetics
use in emergencies glaucoma
pilocarpine
Tox of cholinomimetics in glaucoma?
miosis, cyclospasm
Latonoprost moa in glaucoma? Tox?
prostaglandin that increases outflow of humor; darkens color of iris (browning)
opioid MOA?
opioid receptors to modulate synaptic transmission; open K channels, close Ca channels–>decrease synaptic transmission; inhibit release of ACh, NE, 5HT, glutamate, substance P
opiate used for cough supression?
dextromethorphan
opiate used for diarrhea?
loperamide, diphenoxylate
butorphanol moa?
Mu opioid partial agonist and kappa-opiod receptor agonist–>analgesia; can cause withdrawal symptoms if used with full opioid agonist
tramadol moa? tox?
very weak opioid agonst, inhibits serotonin and NE uptake; used in chronic pain; decreases seizure threshold, serotonin syndrome
ethosuximide use? moa?
1st line for absence seizures; blocks thalamic T-type Ca channels
ethosuximide tox?
EFGHIJ: fatigue, GI distress, Headache, itching, Stevens johnson syndrome
benzodiazepines in epilepsy? moa?
1st line for acute status epilepticus; increase GABA action
1st line for eclampsia seizures?
MgSO4, then benzos
Phenytoin in seizures? moa?
first line in tonic clonic, first line for status epilepticus prophylaxis; increased Na channel inactivation; zero order kinetics;
phenytoin tox?
nystagmus, diplopia, ataxia, sedation, gingival hyperplasia, hisutism, peripheral neuropathy, megaloblastic anemia, teratogenesis, SLE like syndrome, induction of CYP450, LAD, SJ syndrome, osteopenia
drugs responsible for fetal dilantin syndrome?
phenytoin, carbamazepine; intrauterine growth restriction with microcephaly and develop minor dysmorphic craniofacial features and limb defects including hypoplastic nails and distal phalanges
carbamazepine in epilepsy? moa?
first line for simple, complex, tonic/clonic seizures; increases Na channel inactivation;
1st line for trigeminal neuralgia
carbamzepine
carbamazepine tox?
diplopia, ataxia, blood dyscrasias (agranulocytosis, aplastic anemia), liver toxic, teratogenesis, P450 induction, SIADH, SJ syndrome
valproic acid uses?
1st line for tonic/clonic seizures; myoclonic disorders, bipolar disorder
valproic acid moa?
increases Na channel inactivation, increases GABA concentration by inhibiting GABA transaminase;
valproic acid tox?
GI distress, rare but fatal liver tox, neural tube defects in fetus (spina bifida), tremor, weight gain, contraindicated pregnancy
measure before giving valproic acid?
LFTs (liver toxic
Gabapentin uses?
simple, complex, tonic clonic seizures but not first line; also used in peripheral neuropathies, postherpetic neuralgia, migraine prophylaxis, bipolar disorder
Gabapentin moa? tox?
inhibits high voltage Ca channels, designed as GABA analog; sedation, ataxia
Phenobarbital in epilepsy?
1st line in neonates for simple/complex/tonic-clonic; increases GABA action; sedation, tolerance, dependence, P450 induction, cardiorespiratory depression
topiramate moa?
blocks Na channels, increases GABA action
topiramate tx?
sedation, mental dulling, kidney stones, weight loss
lamotrigine moa? tox?
blocks voltage gated Na channels, SJ syndrome (titrate slowly)
levetiracetam moa?
unknown, may modulate GABA and glutamate release
Tiagabine moa?
increases GABA by inhibiting reuptake
vigabatrin moa?
increases GABA by irreversibly inhibiting GABA transaminase
which epilepsy drugs increase GABA action?
benzos, barbituates, valproic acid (inhibit GABA transaminase), topiramate, levetiracetam, tiagabine, vigabatrin
which epilepsy drugs increase Na channel inactivation?
phenytoin, carbamazepine, valproic acid, topiramate, lamotrigine
which epilepsy drugs increase GABA action and increase Na channel inactivation?
valproic acid, topiramate
which epilepsy drugs act on Ca channels?
ethosuximide (blocks thalamic T type); gabapentin (inhibits high voltage activated Ca 2+ channels)
barbituate moa?
facilitates GABA-A action by increasing duration of Cl channel opening–>decr neuron firing
barbituate contraindication?
porphyria; induces CYP450 and increases demand for heme metabolism–>toxic buildup of precursors
benzos, barbs, EtoH all bind which receptor?
GABA-A receptor, ligand gated Cl channel
moa of flumazenil
competitive antagonist at GABA benzo receptor
zolpidem, zaleplon, eszopiclone
non-benzo hypnotics that act via BZ1 subtype of GABA receptor; reversed by flumazenil
anesthetics with low blood solubility…
rapid induction and recovery times
anesthetics with high solubility in lipids…
high potency = 1/MAC
halothane SEs
liver tox, malignant hyperthermia
methoxyflurane SEs
kidney tox; malignant hyperthermi
what can cause malignant hyperthermia?
all inhaled anesthetics except N2O, succinylcholine
IV anesthetic that is effect terminated by redistribution into tissue and fat
barbituates (thiopental); high potency, high solubility, rapid entry into brain
IV anesthetic associated with anterograde amnesia, post-op respiratory depression, low BP
benzodiazepine
IV anesthetic associated with hallucination and bad dreams
arylcyclohexylamines (ketamine) PCP analogs, block NMDA receptors
propofol moa?
potentiates GABA-A receptor
which anesthetics increase cerebral blood flow?
inhaled anesthetics, ketamine
which anesthetics decrease cerebral blood flow?
barbiturates
local anesthetics moa?
block Na channels by binding to specific receptors on inner portion of the channel; preferentially bind to activated Na channels–most effective in rapidly firing neurons
infected tissues need more or less anesthetic?
more anesthetic if alkaline anesthetic cannot penetrate membrane effectively
what is the order of nerve blockade with local anesthetics?
small diamter > large diameter. Myelinated > unmyelinated. smaller size predominates. Loss of pain, temp, touch, pressure in order.
local anesthetic that is cardio toxic?
bupivicaine
succinylcholine moa? tox?
strong Ach receptor agonist–>sustained depolarization, prevents muscle contraction; hypercalcemia/hyperkalemia, malignant hyperthermia
nondepolarizing nmj blockers? moa?
competitive antagonists that compete with Ach for receptors; reverse with neostigmine (given with atropine to prevent muscarinic effects like bradycardia) and other AchE inhibitors
dantrolene moa?
prevents release of Ca2+ from sarcoplasmic reticulum of skeletal muscle
Parkinson drug families?
dopamine agonists; increase dopamine release; prevent dopamine breakdown; curb excess cholinergic activity
bromocriptine, pramipexole, ropinirole
dopamine agonists
amantadine, L-dopa/carbidopa
increase dopamine levels
selegiline
selective MAO type B inhibitor; preferentially metabolizes dopamine over NE and 5-HT; increases dopamine availability
entacapone, tolcapone
COMT inhibitors–prevent L-dopa degradation; increased dopamine
benztropine
anti-muscarinic that improves tremor/rigidity, does not affect bradykinesia
carbidopa
peripheral decarboxylase inhibitor
Alzheimer drugs:
memantine, donepezil/galantoamine/rivastigmine
memantine moa?
NMDA receptor antagonist; prevents excitotoxicity mediated by Ca; Tox: dizziness/confusion/hallucinations
donepezil, galantamine, rivastigmine
AChE inhibitors; Tox: insomnia
Huntington drugs:
Tetrabenzine + reserpine (limit VMAT; limit dopamine vesicle packaging and release); haloperidol: D receptor antagonist
Sumatriptan moa?
5HT 1B/1D agonist; inhibits Trigeminal nerve activation; prevents vasoactive peptide release; induces vasoconstriction; 2 hr half-life; used in acute migraine, cluster headache attacks
sumatriptan contraindication?
patients with CAD or prinzmetals angina because induces coronary vasospasm; mild tingling
