4. Neuropharmacology Flashcards

1
Q

Most important CNS neurotransmitters?

A

Glutamic acid, GABA, ACh, DA, NE, 5HT, opioid peptides

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2
Q

Action of glutamic acid?

A

Direct coupling and G-protein linked on NMDA -> influx of cation -> excitatory

Potential target for ketamine and PCP

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3
Q

Mechanism of ACh?

A

Excitatory and inhibitory on muscarinic receptors by decreasing/increasing K+ efflux by coupling DAG and cAMP

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4
Q

Mechanism of GABA?

A

Increase K+ influx by direct coupling -> inhibitory

Potential target for anticonvulsant, sedatives, hypnotics, some muscle relaxants

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5
Q

What drugs act on GABA?

A
Barbiturates (duration of Cl- ion channel)
Benzos (frequency of Cl- ion channel)
Propofol (GABA-A)
Baclofen (GABA-B)
Valproic acid (high concentration)
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6
Q

Mechanism of flumazenil?

A

Benzo antagonist (decreases frequency)

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7
Q

What nonbenzo drug binds to benzo receptor?

A

Zolpidem (sleep)

Less tolerance and dependence

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8
Q

Name a nonbenzo anxiolytic

A

Buspirone (partial 5HT1A receptor)

No dependence or withdrawal

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9
Q

Side effects of benzos

A

Sedative, amnestic, anxiolytic, antidepressant, muscle relaxant

Not for T1 preg
May result in hypotension/resp depression if with opioids

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10
Q

Benzo withdrawal syndrome

A

Hypertension, tachycardia, muscle twitching, tremulous, diaphoresis, confusion, dysphoria, seizures

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11
Q

Pharm strategy in Parkinson

A

Increase DA activity and decrease ACh at muscarinic in striatum

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12
Q

Midazolam (1-2mg IV): onset and duration

A

Rapid and shortest

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13
Q

Diazepam (2-10mg BID-QID): onset and duration

A

Rapid and longest

aka Valium

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14
Q

Alprazolam (0.25-0.5 mg TID)

A

Intermediate/Intermediate (Antidepressant effect)

aka Xanax

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15
Q

Chlordiazepoxide (5-10mg TID)

A

Intermediate/Long

aka Librium

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16
Q

Lorazepam (1mg TID)

A

Intermediate/Intermediate (liver ok)

aka Ativan

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17
Q

Temazepam (15-30mg)

A

Intermediate/intermediate (liver ok)

aka Resteril

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18
Q

What 3 benzos are not metabolized in the liver?

A

Alprazolam
Temazepam
Oxazepam

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19
Q

What drug increases dopamine function?

A

Levodopa to dopamine by dopa-decarboxylase

Carbidopa blocks peripheral decarboxylation

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20
Q

Tolcapone and entacapone?

A

COMT inhibitor

Enhances CNS uptake of L-dopa; reduces on-off effects

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21
Q

Dopamine receptor agonists (2)

A

Bromocriptine (hallucinations, confusion, psychosis)

Pramipexole/Ropinirole

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22
Q

MAO B inhibitor

A

Selegiline

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23
Q

What drugs decrease ACh function?

A

Benztropine and trihexyphenidyl (M receptor blockers)

Reduce tremor/rigidity, EPS syndrome, but exacerbates tardive dyskinesia and cause atropine-like effects

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24
Q

Why do antipsych drugs cause atropine-like effects, postural hypotension, sexual dysfunction?

A

Block D2 receptors, muscarinic, alpha receptors

25
Q

Side effects of DR antagonists?

A

Akathisia, acute dystonic rxn, extrapyramidal dysfunction, prolactinemia

26
Q

Chronic dopaminergic receptor bockage?

A

Akathisia and tardive dyskinesia months later

27
Q

Neuroleptic malignant syndrome?

A

Hyperthermia, cardiovascular instability, rigidity, altered MS due to enhanced sensitivity of DR to blocking agents

28
Q

Tx of NMS?

A

Bromocriptine and dantrolene

29
Q

Mechanism of TCA

A

Block reuptake of NE and 5HT

Also block muscarinic/alpha receptors (sedation, decrease seizure threshold, cardiotoxicity)

30
Q

Mechanism of SSRI

A

5HT reuptake blocker

Can cause anxiety, agitation, bruxism, sexual dysfunction, seizure, transitory weight loss

31
Q

Serotonin syndrome?

A

Excess seratonergic activity in CNS

Diaphoresis, rigidity, myoclonus, hyperthermia, instability of autonomic NS, seizures

32
Q

Drug of choice for GTC

A

Valproic acid, phenytoin, carbamazepine - prevent Na+ influx through fast Na channel

33
Q

First-line drug for complex partial seizure

A

Carbamazepine

34
Q

Absence seizure tx

A

Ethosuximide (presynaptic calcium influx through type T channels in thalamic neurons)

35
Q

Common side effects of phenytoin

A

Sedation, ataxia, diplopia, acne, gingival overgrowth

36
Q

Common side effects of valproic acid

A

Pancreatitis, hepatotoxicity, thrombocytopenia

37
Q

Meds that lower seizure threshold

A

1) Antidepressants (baclofen)
2) Analgesics (meperidine, fentanyl, tramadol)
3) Anesthetics (methohexital, enflurane)
4) Benzodiazepines
5) Barbiturates and withdrawal of antiepileptic
6) Antibiotics: Cefazolin, imipenem, metronidazole
7) Radiographic contrast materials

38
Q

Propofol infusion syndrome

A

High dose/long-term use of propofol
Metabolic acidosis, cardiac failure, rhabdo, hypotension, death

Using >5mg/kg/h

39
Q

Intrathecal baclofen pump overdose

A

Hallucinations, seizures, confusion, psych, resp depression, hypotension, coma

40
Q

Time course for intrathecal baclofen withdrawal

A

Over 1-3 day

Tx: restoration of baclofen

41
Q

Toxic doses of acetaminophen

A

> 10g/d (lower if liver dx, and taking cytochrome p450 enzyme-inducing drugs)

42
Q

Prescribing NSAIDS

A

Do not create dependence
misoprostol may reduce side effects
ASA is irreversible - inhibits platelet function for 8-10 days.

All can cause water and sodium retention and potential nephrotoxicity

43
Q

Ketorolac (Toradol)

A

Only parenteral. Useful if sensitive to narcotics.

30 mgIV or IM q6h; maximum 120 mg/d

44
Q

Celecoxib

A

COX-2 inhibitor; 200mg 2x daily

45
Q

Most common antispasmodics in spine surgery

A

Little evidence
Cyclobenzaprine, methocarbamol, carisoprodol
Diazepam for muscle spasms

46
Q

1/2 life of cortisone

A

90 min

47
Q

Normal physiologic replacement of steroids (under no stress)

A

Prednisone 5mg qAM and 2.5mg qPM (or hydrocortisone 10mg qAM and 5mg qPM)

48
Q

Which doses of steroids unlikely to cause HPA axis suppression

A

<1w

Axis suppression with 40-60mg after 2w

49
Q

Equivalent corticosteroid doses

A
Dexamethasone 0.75mg
Methylprednisolone 4mg
Prednisone 5mg
Hydrocortisone 20mg
Cortisone 25mg
50
Q

Neurologic side effects of steroids

A

Mental agitation “steroid psychosis”, spinal epidural lipomatosis, multifocal leukoencephalopathy, pseudotumor cerebri

51
Q

Weak opioids, doses and delivery time

A

Codeine 30-60 mg IM/PO q3 PRN
Propoxyphene 1-2 tablets PO q4-6h
Tramadol 50-100mg PO q4-6 PRN

52
Q

Antidote for morphine

A

Naloxone

53
Q

Dexmedetomidine - indication?

A

Anxiety
Opioid sparing analgesia/sedation without resp depression

Allows brain mapping without interfering with electrophysiologic monitoring

54
Q

Dexmedotomidine on traumatic spinal cord injury

A

Decreases inflammation.

55
Q

Two types of antiemetics

A

Phenothiazine (promethazine, prochlorperazine) - lower seizure threshold

Trimethobenzamide - for nausea 2/2 posterior fossa surgery

Metoclopramide - can cause EPS

Ondansetron - n/v post chemo and surgery

56
Q

Why use acid inhibitors in nsu px?

A

Stress ulcers from brain/spinal injury, tumors, ICH, SIADH

57
Q

Acid inhibitors use in NSU patients

A

Ranitidine 150mg PO BID or 50 mg IV Q8
Famotidine 40mg PO (thrombocytopenia)
Omeprazole 20-40mg BID
Sucralfate 1g PO QID

58
Q

Ondansetron mechanism of action

A

5HT3 receptor in area postrema and peripheral sensory/enteric nerves.