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Neurology pharmacology - Coggle Diagram
Neurology pharmacology
epilepsy drugs
gabapentin
for partial epilepsy, peripheral neuropathy, postherpetic neuralgia
adverse: sedation, ataxia
inhibit high-voltage-activated Ca channel; designed as GABA analog
valproic acid
for partial, tonic-clonic, absence epilepsy, myoclonic seizure, bipolar disorder, migraine prophylaxis
adverse: GI distress, fatal hepatotoxicity, pancratitis, neural tube defect, tremor, weight gain, contraindicated in pregnacy
↑Na channel inactivation, ↑GABA concentration
ethosuximide
for absence epilepsy
block thalamic T-type Ca channels
adverse: fatigue, GI distress, headache, itching, Steven-Johnson syndrome
lamotrigine
for partial, tonic-clonic, absence epilepsy
adverse: Stevens-Johnson syndrome
block voltage-gated Na channels, inhibit release of glutamate
tigabine
for partial epilepsy
↑ GABA by inhibiting reuptake
levetiracetam
for partial, tonic-clonic epilepsy
adverse: neuropsychiatric symptoms, fatigue, drowsiness, headache
unknown
carbamazepine
for partial and tonic-clonic epilepsy
adverse: diplopia, ataxia, blood dyscrasias, liver toxicity, teratogenesis, etc
block Na⁺ channel
1st line for trigeminal neuralgia
topiramate
for partial, tonic-clonic epilepsy, migraine prevention
adverse: sedation, mental dulling, kidney stone, weight loss, glaucoma
block Na channel, ↑GABA action
phenobarbital
for partial, tonic-clonic epilepsy, status epilepticus (1st line in neonate), anxiety, insomnia(不眠症)
adverse: sedation, tolerance dependence, etc, respiratory and cardiovascular depression, contraindicated in porphyria
↑ GABA action
phenytoin, fosphenytoin
for partial, tonic-clonic epilepsy, status epilepticus
block Na channel
P450 induction, hirsutism, enlarged gums, nystagmus, teratogenicity, etc
benzodiazepine
for anxiety, spasticity(痙縮), status epilepticus, eclampsia(子癇), detoxification, night terrors, sleepwalking, general anesthetic(麻酔), hypnotic(催眠)
adverse: sedation, tolerance, dependence, respiratory depression
↑GABA action by ↑ frequency of Cl⁻ channel opening
vigabatrin
for partial epilepsy
adverse: permanent visual loss
↑GABA
nonbenzodiazepine hypnotics
for insomnia
adverse: ataxia, headache, confusion
act via BZ₁ subtype of the GABA receptor, short duration
suvorexant
for isomnia
adverse: CNS depression, headache, dizzness, upper respiratory tract infection; contraindicated in narcolepsy, not recommended in liver disease; contraindicated with strong CYP3A4 inhibitor
orexin receptor antagonist
ramelteon
for isomnia
adverse: dizziness, nausea, fatigue, headache
melatonin receptor agonist
triptan
for acute migraine, cluster headache attacks
adverse: coronary vasospasm, mild paresthesia, serotonin syndrome; contraindicated in patient with CAD or Prinzmetal angina
5-HT agonist, inhibit trigeminal nerve activation; induce vasoconstriction
Parkinson disease drugs
↑L-DOPA availability
levodopa/cardidopa: cardidopa block peripheral conversion of L-DOPA
entacapone prevent peripheral L-DOPA degradation, used in conjunction with levodopa
central L-DOPA available for conversion to dopamine, can cross BBB
adverse: nausea, hallucination, postural hypotension
prevent dopamine breakdown
entacapone: block conversion of dopamine to 3-MT by inhibiting central COMT
selegiline, resagiline: block conversion of dopamine into DOPAC by selectively inhibiting MAO-B
↑dopamine availability
amantadine
toxicity: ataxia, livedo reticularis
curb excess cholinergic activity
benztropine, trihexyphenidyl (antimuscarinic)
dopamine agonists
ergot(麦角): bromocriptine
non-ergor: pramipexole, ropinirole; toxicity includes impulse control disorder, postural hypotension, hallucination/confusion
tetrabenazine, reserpine
for Huntington chorea, tardive dyskinesia(遅発性ジスキネジア)
inhibit vesicular monoamine transporter(VMAT) dopamine→↓vesicle packing and release
riluzole
for ALS, ↑survival
↓ neuron glutamate excitotoxicity
Alzheimer disease drugs
memantine
adverse: dizziness, confusion, halliucination
NMDA receptor antagonist; helps prevent excitotoxicity
donepezil, rivastigmine, galantamine
adverse: nausea, dizziness, insomnia
AChE inhibitors
anesthetics
general principles
↓sulubility in blood→rapid induction and recovery time; ↑solubility in lipids→↑potency, 1/MAC
MAC: minimal alveolar concentration required to prevent 50% of subjects from moving in response to noxious stimulus
CNS drug must be lipid-soluble(can cross BBB) or be actively transported
inhaled anesthetics
desflurane, halothane, enflurane, isoflurane, sevoflurane, methoxyflurane, N₂O
myocardial depression, respiratory depression, nausea, emesis(嘔吐), ↑cerebral blood flow
adverse: hepatotoxicity, nephrotoxicity, proconvulsant(けいれん), expansion of trapped gas in a body cavity
malignant hyperthermia
rare, life-threatening condition, fever, severe muscle contraction
susceptibility is often inherited as AD (RYR1 gene)
treatment: dantrolene
intravenous anesthetics
midazolam
procedural sedation, anesthesia induction
respiratory depression, ↓BP, anterograde amnesia
facilitate GABA
propofol
potentiate GABA
rapid induction, short procedure, ICU sedation
thiopental
induction of anesthesia, short surgical procedure
↓ cerebral blood flow, high lipid solubility, effect terminated by rapid redistribution into tissue and fat
facilitate GABA
ketamine
dissociative anesthesia, sympathomimetics(交感神経作用)
↑cerebral blood flow, emergence reaction (disorientation, hallucination, vivid dreams)
NMDA receptor antagonist
local anesthetics
esters=procaine, tetracaine, benzocaine, chloroprocaine; amides=lidocaine, mepivacaine, bupivacaine, ropivacaine
mechanism
block Na channel by binding to specific receptors on inner portion of channel
can be given with vasoconstrictors (↓bleeding, ↑anesthesia)
in infected tissue, cannot penetrate membrane effectively→need more anesthetics
small myelinated>small unmyelinated>large myelinated>large unmyelinated
pain→temperature→touch→pressure
for minor surgical procedure, spinal anesthesia
adverse: CNS excitation, severe cardiovascular toxicity, hypertension, hypotension, arrhythmias, methemoglobinemia
neuromuscular blocking drugs
depolarizing neuromuscular blocking drugs
complications include hypercalcemia, hyperkalemia, malignant hyperthermia
reversal of blockade
phase1: prolonged depolarization, no antidote, block potentiated by cholinesterase inhibitors
phase2: repolarized but blocked, ACh receptors are desensitized; may be reversed with cholinesterase inhibitors
succinylcholine: strong ACh receptor agonist
nondepolarizing neuromuscular blocking drugs
reversal of blockade: neostigmine, edrophonium, other cholinesterase inhibitor
atracurium, cisatracurium, pancuronium, rocuronium, tubocurarine, vecuronium: competitive with ACh for receptors
dantrolene
for malignant hyperthermia and neuroleptic malignant syndrome
prevent release of Ca from sarcoplasmic reticulum
cyclobenzaprine
skeletal muscle relaxant, act within CNS
for muscle spasm
glaucoma drugs
↓IOP via ↓amount of aqueous humor
β-blocker
↓aqueous humor synthesis
timolol, betaxolol, carteolol
α-agonist
apraclonidine, brimonidine→↓aqueous homor synthesis
epinephrine→↓aqueous humor synthesis via vasoconstriction
diuretics
↓aqueous humor synthesis via inhibition of carbonic anhydrase
prostaglandin
↑outflow of aqueous humor via ↓resistance of flow through uveoscleral pathway
cholinomimetics
↑ outflow of aqueous humor via contraction of ciliary muscle and opening of trabecular meshwark
use pilocarpine in acute angle closure glaucoma
baclofen
skeletal muscle relaxant, GABA receptor agonist in spinal cord
muscle spasticity(筋痙縮), dystonia, multiple sclerosis
opioid analgesics
types
full agonist: morphine, heroine, meperidine, methadone, codeine
partial agonist: buprenorphine
mixed agonist/antagonist: nalbuphine, pentazocine
antagonist: naloxone, naltrexone, methylnaltrexone
adverse: nausea, vomiting, pruritus, addiction, respiratory depression, constipation, sphincter of Oddi spasm, miosis, CNS depression,,,
act as agonist at opioid receptors to modulate synaptic transmission; close presynaptic Ca channel, open postsynaptic K channel
for severe or refractory pain, cough supression, diarrhea, acute pulmonary edema, maintenance programs for heroin addicts
pentazocine
for analgesia(鎮痛) to severe pain
k-opioid receptor agonist and μ-opioid receptor weak antagonist or partial agonist
butorphanol
for severe pain, less respiratory depression
use with full opioid agonist can precipitate withdrawal
k-opioid receptor agonist and μ-opioid receptor partial agonist
tramadol
very weak opioid agonist
for chronic pain