Neurology Flashcards
Decrease aqueous humor synthesis
via vasoconstriction
For open-angle glaucoma
SE: mydriasis
Contra: closed-angle glaucoma
Epinephrine
Alpha-agonist
Decreases aqueous humor synthesis
For glaucoma
SE: blurry vision, ocular hyperemia, foreign body sensation, ocular allergic reactions, ocular pruritis
Brimonidine
Beta-blockers (3)
Decrease aqueous humor synthesis
For glaucoma
Timolol, betaxolol, carteolol
Decreases aqueous humor synthesis
via inhibition of carbonic anhydrase
Acetazolamide
Increase outflow of aqueous humor
via contraction of ciliary muscle, opening of trabecular meshwork
SE: miosis, cyclospasm (ciliary muscle)
Which one for emergencies?
Direct cholinomimetics
Pilocarpine, carbachol
Indirect
Physostigmine, echothiophate
Emergencies- pilocarpine
open meshwork into canal of Schlemm
Increase outflow of aqueous humor
Darkens color of iris (browning)
Latanoprost
(prostaglandin F2alpha)
Opioid receptor agonist for:
Mu
Delta
Kappa
Mu - morphine
Delta- enkephalin
Kappa- dynorphin
Opioid receptor agonists
Open K+, close Ca2+ channels, limit synaptic transmission
Inhibit release of ACh, NE, 5-HT, glutamate, substance P
For pain, cough supression (1), diarrhea (2), acute pulmonary edema, maintenance for addicts (1)
SEs: addiction, respiratory depression, constipation, miosis, CNS depression.
Toxicity treatment?
Opioid analgesics
Morphine, fentanyl, codeine, heroin, methadone, meperidine, dextromethorphan, diphenoxylate
cough- dextromethorphan
diarrhea- loperamide, diphenoxylate
addiction- methadone
OD Tx: naloxone, naltrexone
Mu receptor partial agonist, kappa receptor agonist
For severe pain (migraine, labor)
Less resp depression
SE: opioid withdrawal if given with full opioid agonists
Butorphanol
OD not reversed with naloxone
Weak opioid agonist
inhibits serotonin, NE reuptake
For chronic pain
SE: similar to opioids, decreased seizure threshold
Tramadol
Na+ channel inactivation
inhibits glutamate release from excitatory presynaptic neuron
1st line: status epilepticus (prophylaxis), tonic-clonic seizure
Also for simple and complex partial seizures
SEs: many
Phenytoin
Nystagmus, diplopia, ataxia, sedation,
gingival hyperplasia, hirsutism, megaloblastic anemia,
teratogenesis, SLE-like syndrome, P450 inducer,
lymphadenopathy, Stevens-Johnson syndrome,
osteopenia
Phenytoin toxicity
Increases Na+ channel inactivation
1st line: simple and complex partial seizures, tonic-clonic seizures, trigeminal neuralgia
Diplopia, ataxia, blood dyscrasias (agranulocytosis, aplastic anemia), liver toxicity, teratogenesis, P450 inducer, SIADH, Stevens-Johnson syndrome
Carbamazepine
Prodrome of malaise, fever
Rapid onset erythematous/purpuric macules (oral, ocular, genital)
Progress to epidermal necrosis and sloughing
Stevens-Johnson syndrome
Blocks voltage-gated Na+ channels
For simple and complex partial seizures, tonic-clonic
Stevens-Johnson syndrome
Lamotrigine
GABA analog
inhibits high-voltage activated Ca2+ channels
For simple, complex partial seizures and tonic-clonic
Also for peripheral neuropathy, postherpetic neuralgia, migraine prophylaxis, bipolar
SE: sedation, ataxia
Gabapentin
Blocks Na+ channels, increase GABA action
For simple, partial complex and tonic-clonic seizures
Also for migrain prevention
SE: sedation, mental dulling, kidney stones, weight loss
Topiramate
Increase GABA-A action
1st line in children
for simple, partial complex seizures and tonic-clonic
SE: sedation, tolerance, dependence, P450 inducer
Phenobarbital
Increase Na+ channel inactivation
Increase GABA concentration
1st line for tonic-clonic
Also for simple, complex partial and absence seizures
Also for myoclonic seizures
SE: GI distress, rare hepatotoxicity, neural tube defects, tremor, weight gain
Contra: pregnancy
Valproic acid
Blocks thalamic T-type Ca2+ channels
For absence seizures
SE: GI distress, fatigue, headache, urticaria, Stevens-Johnson syndrome
Ethosuximide
Increases GABA-A action
1st line: status epilepticus (acute)
Also for seizures of eclampsia
SE: sedation, tolerance, dependence
Benzodiazepines
(diazepam, lorazepam)
Inhibits GABA reuptake
For simple, complex partial seizures
Tiagabine
Irreversible GABA transaminase inhibitor
Increases GABA
For simple, complex partial seizures
Vigabatrin
Unknown mechanism
May modulate GABA, glutamate release
For simple, complex partial and tonic-clonic seizures
Levetiracetam
Increases duration of Cl- channel opening
Facilitates GABA-A action, decreased neuron firing
For anxiety, seizures, insomnia, anesthesia
SE: respiratory, cardiovascular depression, CNS depression, dependence, drug interactions (P450 inducer)
Contra: porphyria
OD Tx: supportive
Barbiturates
phenobarbital, pentobarbital, thiopental, secobarbital
Increases frequency of Cl- channel opening
Facilitates GABA-A
For anxiety, spasticity, status epilepticus (2), detoxification (DT), night terrors, sleepwalking, general anesthetic, hypnotic (insomnia)
SE: dependence, CNS depression (esp. w/EtOH), some respiratory depression.
OD Tx: flumazenil
Benzodiazepines
Diazepam, lorazepam, triazolam, temazepam, oxazepam, midazolam, chlordiazepoxide, alprazolam
Short-acting:
triazolam, oxazepam, midazolam
increased risk for addiction
Acts on BZ1 subtype of GABA receptor (3)
For insomnia
SE: ataxia, headaches, confusion
Modest day-after psychomotor depression, little amnesia, lower dependence risk
OD Tx: flumazenil
Nonbenzodiazepine hypnotics
Zolpidem (Ambien), zaleplon, eszopiclone
Anesthetics
Rapid induction, recovery increases with?
Potency increases with?
Increased potency = increased 1/MAC
What is MAC?
Rapid induction, recover increases with low blood solubility
Potency increases with high lipid solubility
MAC is minimal alveolar concentration at which 50% of population in anesthetized.
N2O- low solubility - fast induction, low potency
Halothane- high solubility- slow induction, high potency
Unknown mechanism
For general anesthesia
Causes myocardial depression, respiratory depression, nausea/emesis, increased cerebral blood flow
SE: hepatotoxicity (1), nephrotoxicity (1), proconvulsive (1), malignant hyperthermia, expansion of trapped gas (1)
Inhaled anesthetics
Halothane, enflurane, isoflurane, sevoflurane, methoxyflurane, nitrous oxide
hepatotoxicity- halothane
nephrotoxicity- methoxyflurane
proconvulsive- enflurane
malignant hyperthermia- all but nitrous oxide
expansion of trapped gas- nitrous oxide
Highly potent, lipid soluble anesthetic
Barbiturate
Rapid induction of anesthesia for short procedures
Effects terminated by redistribution into tissue and fat
Decrease cerebral blood flow
Thiopental
Benzodiazepine
Most commonly used in endoscopy
(with inhaled anesthetics and narcotics)
SE: respiratory depression, drop in BP, amnesia
OD Tx: flumazenil
Midazolam
Dissociative anesthetic
PCP analog
Blocks NMDA receptors
Cardiovascular stimulant
SE: disorientation, hallucination, bad dreams
Increased cerebral blood flow
Ketamine
(arylcyclohexylamines)
Opioids (2)
For general anesthesia
with other CNS depressants
Morphine
Fentanyl
For rapid anesthesia induction
Sedation in ICU
Potentiates GABA-A
Less nausea than thiopental
Propofol
Preferentially bind activated Na+ channels
Bind specific receptors on inner portion of channel
Epinephrine increases local action
For minor surgical procedures, spinal anesthesia
SE: CNS excitation, cardiovascular toxicity (1), HTN, hypotension, arrhythmias (1)
Local anesthetics
Esters (may cause allergy)- procaine, cocaine, tetracaine
Amides- lidocaine, mepivacaine, bupivacaine
Order of loss: pain, temp, touch, pressure
Cardiovascular toxicity- bupivacaine
Arrhythmias- cocaine
More anesthetic needed if tissue infected.
ACh receptor agonist
Prevents muscle contraction w/sustained depolarization
For muscle paralysis in surgery or mechanical ventilation
Selective for motor nicotinic receptors
SE: hypercalcemia, hyperkalemia, malignant hyperthermia
Succinylcholine
Reversal of blockade
Phase I - prolonged depolarization
Antidote, what potentiates?
Phase II- repolarized, but blocked (receptors desensitized)
Antidote
Phase I
No antidote
Potentiated by cholinesterase inhibitors
Phase II
Antidote is cholinesterase inhibitor
(neostigmine)
Competitive ACh antagonists
Nondepolarizing
Antidote?
Curare drugs
Tubocurarine, atracurium, mivacurium, pancuronium, vecuronium, rocuronium
Antidote: cholinesterase inhibitor
(neostigmine, edrophonium)
Blocks Ca2+ release from sarcoplasmic reticulum
For malignant hyperthermia
(side-effect of inhalation anesthetics and succinylcholine)
And neuroleptic malignant syndrome
(antipsychotic toxicity)
Dantrolene
Dopamine agonists
(3)
For Parkinson’s
Ergot:
Bromocriptine
Non-ergot:
Pramipexole, ropinirole
(Non-ergots preferred)
Increases dopamine levels
(2)
For Parkinson’s
Amantadine
(SE: ataxia)
L-DOPA/carbidopa
Prevents dopamine breakdown
(1 MAOI, 2 COMTI)
For Parkinson’s
MAO-B inhibitor:
Selegiline
COMT inhibitors:
entacapone, tolcapone
Antimuscarinic
Curbs excess cholinergic activity
For Parkinson’s
Improves tremor, rigidity
Little effect on bradykinesia
Benzotropine
(park your benz)
Increases level of dopamine in brain
Converted to dopamine by dopa decarboxylase
Adjunct is peripheral decarboxylase inhibitor
For Parkinson’s
SE: arrhythmias (increased catecholamine production), dyskinesia after use, akinesia between uses
L-dopa/carbidopa
Selectively inhibits MAO-B
(metabolizes DA over NE, 5HT)
For Parkinson’s
Adjunct to L-dopa, may enhance side effects
Selegiline
NMDA receptor antagonist
Prevents excitotoxicity (Ca2+ mediated)
For Alzheimer’s
SE: dizziness, confusion, hallucinations
Memantine
Acetylcholinesterase inhibitors
(3)
For Alzheimer’s
SE: nausea, dizziness, insomnia
Donepezil, galantamine, rivastigmine
Inhibit VMAT
(2)
Limit dopamine packaging and release
For Huntington’s
Tetrabenazine, reserpine
DA receptor antagonist
For Huntington’s
Haloperidol
5-HT 1B/1D agonist
Inhibits CN V activation
Prevents vasoactive peptide release –> vasoconstriction
For acute migraine, cluster headache attacks
SE: coronary vasospasm, tingling
Contra: Prinzmetal’s angina, CAD
Sumatriptan
