Neurology Flashcards by M B

Decrease aqueous humor synthesis

via vasoconstriction

For open-angle glaucoma

SE: mydriasis

Contra: closed-angle glaucoma

Epinephrine

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Alpha-agonist

Decreases aqueous humor synthesis

For glaucoma

SE: blurry vision, ocular hyperemia, foreign body sensation, ocular allergic reactions, ocular pruritis

Brimonidine

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Beta-blockers (3)

Decrease aqueous humor synthesis

For glaucoma

Timolol, betaxolol, carteolol

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Decreases aqueous humor synthesis

via inhibition of carbonic anhydrase

Acetazolamide

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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

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Increase outflow of aqueous humor

Darkens color of iris (browning)

Latanoprost

(prostaglandin F2alpha)

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Opioid receptor agonist for:

Delta

Kappa

Mu - morphine

Delta- enkephalin

Kappa- dynorphin

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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

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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

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Weak opioid agonist

inhibits serotonin, NE reuptake

For chronic pain

SE: similar to opioids, decreased seizure threshold

Tramadol

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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

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Nystagmus, diplopia, ataxia, sedation,

gingival hyperplasia, hirsutism, megaloblastic anemia,

teratogenesis, SLE-like syndrome, P450 inducer,

lymphadenopathy, Stevens-Johnson syndrome,

osteopenia

Phenytoin toxicity

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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

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Prodrome of malaise, fever

Rapid onset erythematous/purpuric macules (oral, ocular, genital)

Progress to epidermal necrosis and sloughing

Stevens-Johnson syndrome

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Blocks voltage-gated Na+ channels

For simple and complex partial seizures, tonic-clonic

Stevens-Johnson syndrome

Lamotrigine

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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

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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

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Increase GABA-A action

1st line in children

for simple, partial complex seizures and tonic-clonic

SE: sedation, tolerance, dependence, P450 inducer

Phenobarbital

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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

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Blocks thalamic T-type Ca2+ channels

For absence seizures

SE: GI distress, fatigue, headache, urticaria, Stevens-Johnson syndrome

Ethosuximide

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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