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Pharmacy School 2015-16 > PHAR 736 Final Exam (Filtz) > Flashcards

PHAR 736 Final Exam (Filtz) Flashcards

1
Q

N(N) Receptors

A

Neuronal Nicotinic receptors on post-gangliconic neurons and adrenal medulla

5 subunits forming a barrel with inner poor to allow cations to pass through

Required binding of 2 molecules of ACh

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2
Q

Nicotinic receptor antagonists

A

Non-depolarizing (flaccid paralysis)

Competitively blocks ACh binding sites (can be overcome by more ACh)

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3
Q

Nicotinic receptor agonists

A

Depolarizing blocker (spastic paralysis)

Persistent stimulation induced blockade, akin to desensitization

Blockade NOT to be reversed by excess ACh; must wait for resensitization

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4
Q

N(M) blockers cause paralysis of

A

voluntary, striated, skeletal muscle

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5
Q

Curare

A

Classic natural product paralytic agent

Used in South America to paralyze prey

No initial excitation, only blockade resulting in paralysis (80-120min)

Sequential order of paralysis: Eye, jaw, throat and neck, appendages, abdominal muscles, intercostal muscles and diaphragm

Dose can be titrated to avoid asphyxiation but produce waking paralysis

Poisoning treatable with AChE inhibitors

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6
Q

Problems with curare and curare-like drugs

A

Action terminated by excretion in urine so may have extended duration in patients with renal insufficiency

Histamine release also associated with curare, so be careful with asthmatics

Potentially dangerous synergism with antibiotics (streptomycin, tetracyclin)

> antibiotics chelate Ca2+ and contribute to muscle paralysis
Antibiotics prolong duration of action of curare-like drugs beyond expectations

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7
Q

Synthetic curare-like drugs

A

No histamine release

Drugs terminated by renal elimination are better for patients with liver disease, and vice versa

Cisatracurium, Pancuronium, Vecuronium, Rocuronium

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8
Q

Cisatracurium

A

Medium duration (30-40 minutes)

Nm selective because it cannot cross into the ganglionic space

Terminated by metabolism

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9
Q

Pancuronium, Vecuronium, Rocuronium

A

Greater selectivity for Nm over Nn receptors that cisatracurium

Pancuronium is long-lived (120-180 min), renal elimination (great for surgery and for those with liver disease)

Rocuronium and Vecuronium are of intermediate duration, liver metabolized, and can be chemically antagonized by sugammadex.

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10
Q

Succinylcholine

A

Depolarizing neuromuscular blocker; cheap, rapid acting and short duration

Nm selective

Opens ion channel, causing initial depolarization leading to contracting and twitching for 1 minute; persistent stimulation = eventual blockade (~5 minute paralysis)

Succinylcholine hydrolyzed by circulating plasma cholinesterases (pseudocholinesterases) and has short duration

Short term paralysis makes it useful for electroshock therapy, setting fractures and dislocations, endotracheal intubations)

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11
Q

Problems with succinylcholine

A

No chemical antidote for depolarizing blocker

May have muscle pain and soreness from initial twitching

Hyperkalemia due to affinity for K+ channels (problematic for those on digitalis or with electrolyte imbalances)

Duration may be dangerously extended in patients with liver disease or genetic defects resulting in low levels of circulating cholinesterase

May cause malignant hyperthermia when used in conjunction with inhalation anesthetics in some patients

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12
Q

Malignant Hyperthermia

A

Results from Succinylcholine + inhaled anaesthetic causing hypermetabolic response of muscle tissue due to excess calcium release

Treat with Dantrolene (blocks Ca2+ release from SR)

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13
Q

Tetrodotoxin

A

Bacterial toxin concentrated by marine organisms such as pufferfish

Na+ channel blocker that interrupts axonal conductance

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14
Q

Botulin toxin

A

From Clostridium botulinum of food-poisoning fame

Inhibits Ca2+ dependent binding of vesicles to plasma membranes thereby inhibiting neurotransmitter release

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15
Q

Predominant tone and effect of ganglionic blockade effect on Blood Vessels

A

Sympathetic; hypotension

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16
Q

Predominant tone and effect of ganglionic blockade effect on Bladder and GI sphincters

A

Sympathetic; Relaxation

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17
Q

Predominant tone and effect of ganglionic blockade effect on Heart

A

Parasympathetic; Tachycardia

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18
Q

Predominant tone and effect of ganglionic blockade effect on Eye

A

Parasympathetic; Mydriasis, blurred vision

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19
Q

Predominant tone and effect of ganglionic blockade effect on GI Tract

A

Parasympathetic; Decreased motility

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20
Q

Predominant tone and effect of ganglionic blockade effect on Urinary Bladder

A

Parasympathetic; Urinary retention

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21
Q

Predominant tone and effect of ganglionic blockade effect on Salivary glands

A

Parasympathetic; dry mouth

22
Q

Non-depolarizing and depolarizing ganglionic blockers have __________________ clinical use

A

very-limited

No antidote for depolarizing, induce vomiting

23
Q

Nicotine

A

Some selectivity for Nn over Nm

At high dose, Nm receptor effects cause muscle twitching

Most noticeable effect is initial EPI release following excitation of adrenal medualla Nn receptors (increase in HR, BP)

Nicotine dependency/addictive properties based on CNS effects

Special effects include: concentrated nicotine is lethal; analgesia following through blockade of pain sensory nerves; nausea and vomiting from activation of vomiting reflex center; respiratory distress and hyperventilation (activation of chemosensory nerves); and may have neuroprotective, anxiolytic or GI protective effects

24
Q

Varenicline

A

Partial agonist at (a4)2(b2)3 and full agonist at (a7)5 nicotinic receptors

Predominant CNS nicotinic receptor subtypes

Nicotine withdrawal symptoms due to elevated receptor levels - irritability, insomnia, restlessness, aches and pains, constipation, increased appetite, sugar cravings

As a partial agonist, will reduce withdrawal symptoms without activating dependency pathways (doubles abstinence rate compared to placebo over 52 weeks)

25
Q

Draw graph of verenicline by itself and in presence if nicotine

A

…

26
Q

ACHe inhibitors that do not pass the BBB and ganglionic barriers will increase ACh levels to

A

Affect muscarinic receptors on PNS target organs

Affect Nm receptors on skeletal muscle

27
Q

Inhibitors of AChE that DO pass the BBB and ganglionic barriers will

A

Affect Nn receptors in autonomic ganglia

Affect Nn receptors on adrenal medulla

Affect Nn and muscarinic receptors in the CNS

28
Q

Pseudocholinesterase

A

Produced by the liver and in the circulation

AKA butyryl cholinesterase

29
Q

Indications for AChE inhibitors

A

Nm effects, Nn (ganglionic) effects, muscarinic (M) effects, CNS effects

30
Q

Describe Nm effects of AChE inhibitors

A

For Myasthenia Gravis (antibodies attack and destroy Nm, not Nn, receptors)

> diagnosis can be made with AChE inhibitors which have no effect on other muscle diseases characterized by weakness
symptoms treated by increasing ACh levels at neuromuscular junction
longterm treatmnet may involve thymectomy or immune suppression

Also used to reverse effects of non-depolarizing (competitive) Nm blockers

31
Q

AChE inhibitors ganglionic (Nn) effects

A

Orthostatic hypotension

Prolongs ganglionic transmission leading to increased basal tone

32
Q

AChE inhibitors muscarininc effects

A

Glaucoma (increases miosis through MI and M3 receptor activation on iris sphincter; increased aqueous humor flow through contraction of ciliary muscle)

Antidote to poisoning by deadly nightshade (atropine) or other muscarinic antagonist (competitive antagonist actions overcome by excess agonist)

GI and Bladder atony-limited use (increased GI motility and bladder emptying through activation of muscarinic receptors in gut and bladder, smooth muscle and sphincters)

Paroxysmal atrial tachycardia-very limited use (decrease heart rate through M2 receptor activation on cardiac muscle)

33
Q

AChE inhibitors CNS effects

A

Treatment of Alzheimer’s disease (increasing ACh levels in CNS have short term therapeutic benefit; longterm loss of cholinergic neurons eventually render AChE inhibitors impotent)

34
Q

Side effects with AChE inhibitors

A

Secretory, cardiac, bronchiol, and GI effects same as with a muscarinic receptor agonist (may decrease over time, can be controlled by concurrent admin of muscarinic antagonist, and at toxic levels hypoxia activates chemosensory reflexes to increase HR)

Actions on the vasculature (No ACh to release at vascular endothelium so vascular muscarinic receptor not affected; AChE inhibitors may have unpredictable effects on BP depending on degree of ganglionic stimulation, basal tone of blood vessels, age and level of excitement)

CNS effects may cause confusion, convulsions and coma at toxic doses

Skeletal muscle activation of twitching, eventual paralysis and death by asphyxiation at toxic doses

35
Q

Physostigmine

A

AChE inhibitor

Natural plant alkalpoid and prototype

Penetrates peripheral ganglia and CNS - proposed use to treat orthostatic hypotension

Used topically to treat glaucoma

36
Q

Neostigmine

A

AChE Inhibitor

Does not cross BBB

Most used for management of myasthenia gravis

Useful for atropine poisoning

Useful for GI and bladder atony

37
Q

Edrophonium

A

AChE inhibitor

Short duration of action

Used to diagnose myasthenia gravis because it washes away quickly

38
Q

Pyridostigmine bromide

A

AChE inhibitor

Approved for prophylactic use by military to potentially block effects from a feared nerve gas attack

never been clinically tested for this use

39
Q

Rivastigmine

A

AChE inhibitor for Alzheimer’s

Crosses BBB

Approved for mild to moderate dementia in Parkinson’s; may target AChE isoenzymes that are more prominent in the CNS; fewer reported side effects than donepezil, particularly less bradycardia

40
Q

Donepezil, Galantamine

A

AChE inhibitors used in Alzheimer’s

Cross BBB

41
Q

Huperzine A

A

AChE inhibitor used in Alzheimer’s treatment

Cross BBB

Herbal product

42
Q

Organophosphates

A

Irreversible AChE inhibitors

Aging of phosphorylated AChE (in 1 hour) leads to permanently phosphorylated enzyme that can NOT be reactivated

Very lipid soluble and readily cross the BBB, pulmonary and intestinal membranes

Echothiophate, Nerve gases (Sarin, Tabun, Soman, VX), Insecticides (Malathion, Parathion)

43
Q

Echothiophate

A

Very long duration of action

Used topically to treat glaucoma

Decreased lipid solubility and limited systemic absorbance

44
Q

Nerve Gases (Sarin, Tabun, Soman, VX)

A

Airborne organophosphates

Rapidly cross membranes and barriers

Death from asphyxiation may result in minutes

45
Q

Insecticides (Malathion, Parathion)

A

Can be detoxified rapidly by mammals

Over-exposure is similar to nerve gas poisoning

46
Q

Treatment of organophosphate poisoning

A

Support respiration plus atropine + Pralidoxime

  • give atropine within seconds to minutes to reverse muscarinic effects
  • *pralidoxime, an oxime reactivator of AChE must be given within minutes to hours of exposure
  • **support respiration to avoid patient asphyxiation or drowning in secretions

No antidote available if sufficient time has passed for aging of phosphorylated AChE to occur

47
Q

Acute Glaucoma

A

Closed angle

Characterized by an abnormal lodging of the iris against the lens, impeding the flow of aqueous humor, leading to increased intraocular pressure

48
Q

Chronic Glaucoma

A

Open angle

Characterized by excess aqueous humor, from either overproduction or impaired absorption by the Canal of Schlemm

49
Q

Treatment of closed angle glaucoma

A

Best treated by pupillary constrictors

Cholinomimetics (problems with far and night vision)

Constrict the iris sphincter and dislodge the iris, opening a pathway for aqueous humor flow

Contraction of the ciliary muscle increases space for aqueous humor flow through the ciliary ligaments

50
Q

Treatment for chronic open angle glaucoma

A

Use agents that inhibit production of aqueous humor

B-adrenergic receptor antagonists (problems with concurrent airway disease)

a2 adrenergic receptor agonists (problems with drug reactions through alkylation)

Carbonic anhydrase inhibitors, dorzolamide and brinzolamide (carbonic anhydraw is required enzyme for aqueous humor production; systemic administration of inhibitors can cause metabolic acidosis, leading to kidney stones and allergic reactions)

May also be treated with agents that increase aqueous humor drainage (prostaglandin analogues - latanoprost, bimatoprost, travoprost, tafluprost)

51
Q

Prostaglandin analogues side effects

A

Irreversible increase in pigmentation of the iris, eyelid, and lashes

Cosmetically will increase eye lash growth (bimatoprost = Latisse)

52
Q

Alternative glaucoma remedies

A

Cannabinoids, medical marijuana, including delta9-tetrahydrocannabinol

MOA to reduce intraocular pressure not well understood

Tolerance develops

Take systemically due to no topical penetrance

Pharmacy School 2015-16 (34 decks)

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