Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pharmacology > Adrebergic System > Flashcards

Adrebergic System Flashcards

1
Q

Possibilities to influence the adrenergic system

A

Presynaptic stimulation
Postsynaptic stimulation
= sympathomimetics

Presynaptic inhibition
Poststnaptic inhibition
= sympatholytics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Presynaptic stimulation

A
  1. synthesis:
    - precursor substance = levodopa
  2. release:
    - depolarization = 4-aminopyridine/fampiridin
    K+ channel blocker
    - increased ca2+ concentration
    - latrotoxin - explosive release of NE
  3. Presynaptic receptors
    - activation of presynaptic stimulatory b2 receptors
    - inhibition of presynaptic inhibitory a2 receptors (yohimbine, mianserine)
    - activation of presynaptic stimulatory hereroreceptors (AT1)
  4. Indirectly acting sympathomimetics
    - thyramine, ephedrine, ampthanine, they promote transmitter release
  5. Reuptake inhibitors
    - cocaine, tricyclic antidepressants (amitryptyline, desipramine)
  6. MAO inhibitors
    - tranylcypromine, selegiline, moclobemid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Postsynaptic stimulation groups

A

Direct acting sympathomimetics

  • catecholamines
  • b1 receptor agonist
  • b2 receptor agonist
  • a1 receptor agonist

Indirectly acting sympathomimetics

  • tyramine
  • ephedrine
  • amphetamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Catecholamines

A

Direct acting sympathomimetics

```
Epinephrine/adrenaline
Norepinephrine/noradrenaline
Isoprenaline
Dopamine
Dobutamine and dopexanine
~~~

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Epinephrine/adrenaline

A

Direct acting sympathomimetics
- activate all adrenergic receptors
- vasodilation = b2
- vasoconstriction = a1
— determined by receptor distribution (MAP IS NOT CHANGED)
- positive inotropic and chromotropic actions on the heart
- bronchodilation
- indication; anaphylactic shock, emergency heart block and cardiac arrest, asthmatic state, inhaled E for croup/subglottic laryngitis, reduction of regional blood flows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Norepinephrine/noradrenaline

A

Direct acting sympathomimetics

  • activates a and b1 receptors, but little effect on b2
  • vasoconstriction and increased BP
  • Compensatory vagal reflexes can overcome its direct positive chronitropic effect on heart
  • indication: neurogenic shock, septic shock, cardiogeic shock and locally to reduce blood flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Isoprenaline

A

Direct acting sympathomimetics

  • potent and selective b receptor agonist
  • positive inotropic and chronitropic action on heart
  • vasodilation, decreased diastolic pressure, and decreased MAP
  • bronchodilation
  • indication: bradycardia and AV blocks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Dopamine

A

Direct acting sympathomimetics

  • low dose: d1 receptor
  • medium dose: b1 receptor
  • high dose: a receptor (act as e)
    Indication: cardiogenic shock (low to medium dose).
    Adverse effects: tachycardia, tolerance,
  • bad pharmacokinetics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Selective b1 receptor agonist

A

Dopamine in medium dose
Dobutamine
Ibopamine
Prenalterol

Indication: cardiogenic shock, limited use in CHF

Adverse effects: tachycardia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Peripheral D receptor agonists

A
  • Dopamine in low dose: dilation of mesenteric and renal blood vessels
  • fenoldopam: peripheral vasodilation in mesenteric vascular bed, for severe hypertension
  • dopexamine: D, B2, (b1) agonist, reuptake inhibitor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Selective b2 receptor agonist

A

Main action and indication
- bronchodilation (COPD, asthma)
—SABA; salbutamol, terbutaline, fenoterol, levosalbutamol
—LABA; salmeterol, formoterol, clenbuterol, bambuterol, procaterol, indacaterol, clodaterol, vilanterol

  • relaxation of pregnant uterus
    — terbutaline, ritodrine

Potential adverse effects
- tremor, tachycardia, hyperglycemia, hypokalemia

No absolute specificity - if possible= topical use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Alpha receptor agonists

- local and systemic use

A

1.Local use - nasal decongestant; activates a1 and a2
- naphazolin, xylometazolin, oxymetazoline, phenylephrin
— vasoconstriction locally
— side effects: rebound hyperemia, ischemic changes of mucous membranes

  1. Local use - ophthalmologic use
    - decongesion - phenylephrin
    - myadriasis - phenylephrin
    - glaucoma - apraclonidine, brimonidine a1
  2. Systemic use
    - selectivity is extremely important
    - a1 selective agonist = sympathomimetics
    —vasoconstriction and increased BP
    —phenylephrin, midodrine, methoxamine
    - a2 selective agonist = sympatholytic
    — due to enhanced negative feedback
    — decreased BP (transient increase)
    — clonidine, guanfacin
    — used as antihypertensive agents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Indirectly acting sympathomimetics

A

They release NE from nerve terminals, rapid development of tolerance

  • tyramine
  • ephedrine
  • amphetamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Tyramine

A

Indirect acting sympathomimetics

  • not used as therapeutic agent
  • found in cheese, chicken liver, red wine
  • metabolized by MAO-a in GI tract and inactivated
  • if treated with MAO-a inhibitors= avoid food with tyramine - can cause hypertensive crisis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ephedrine

A

Indirect acting sympathomimetics

  • alkaloid
  • high oral bioavailability,
  • long action of duration
  • penetrate bbb, mild stimulant
  • mixed sympathomimetic mechanism of action: weak receptor activator and release NE
  • vasoconstrictor or bronchodilator when weak and prolonged action is needed
  • enantiomer- pseudoephedrine= over the counter drug
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Amphetamine

A

Indirect acting sympathomimetics
- orally active compound with long duration
- enters CNS easily and release biological amines and cause a marked stimulant effect on mood and alertness
- euphoria =abuse
- decreased appetite
- periphery= indirectly acting sympathomimetic
- related drugs;
— methylpheridate - ADHD
— MDMA
— methamphetanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Reuptake inhibitors

A

Cocaine
TCA and related compound
SNRI, SSNRI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Cocaine

A

Reuptake inhibitor

  • LA
  • block NE and D reuptake on periphery and CNS
  • sympathomimetics
  • euphoria = abuse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

TCA and related compounds

A

Reuptake inhibitors

  • desipramadine, amitriptyline
  • used to treat mental depression
  • block NE reuptake in PNS + CNS
  • a and m blockade may complicate their autonomic action - risk of adverse cardinal effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

SNRI, SSNRI

A

Reuptake inhibitors
- serotinin NE reuptake inhibitors and selective serotonin ne reuptake inhibitors
—reboxetine, venlafaxine
— antidepressant, no receptor blockade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

MAO Inhibitors

A

Irreversible, non-selective

  • tranylcypromine, parglycine
  • antidepressants- not used due to severe side effects

Reversible mao-a inhibitors

  • modobemid
  • treat mental depression

Irreversible mao-b inhibitors

  • selegiline
  • Parkinson’s
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Presynaptic inhibition = sympatholytics

A
  1. A-methyltyrosine/methyrosine
    - blocks tyrosine hydroxylase enzyme
  2. Reserpine
    - prevents transmitter release
  3. tetrodotoxin, saxitoxin
    - LA
    - prevent/block VGSC
  4. Omega-conotixin
    - block ca2+ channels
  5. Activation of inhibitory presynaptic a2 autoreceptors
    - clonidine, methyldopa
  6. Activation of presynaptic inhibitory heteroreceptors
    - m2, d2, h3, etc
  7. Adrenergic neuron blockers
    - guanethidin and bretylium
    - inhibit transmission release
  8. 6-OH-dopamine
    - destroy the nerve terminal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Postsynaptic inhibition

Groups

A

Decrease sympathetic activity

  1. Beta-blockers
    - non-selective
    - cardioselective/b1 selective
  2. A1 antagonist
    - selective a1 antagonist
    - non-selective a antagonist
  3. A2 receptor agonist
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Non-selective beta blockers

A 
Propranolol 
Pindolol 
Timolol
Sotalol (also: k+ channel blocker)
Carvediol (also: a1 blocker)
Labetalol (also: a1 blocker)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
B1 selective/cardioselective beta blockers
``` Atenolol Metoprolol Bisoprolol Esmolol Celiprolol Betaxolol Nebivolol Acebutolol ```
26
Partial agonistic activity of beta blockers = ISA | intrinsic sympathomimetic activity
``` Pindolol Acebutolol Oxprenolol Alprenolol Celiprolol- bronchoconstriction ``` ISA at b2 receptors Less likely with decreased HR and lipid abnormalities in plasma
27
Consequence of beta blocking
- negative chronotropic and inotropic actions on heart - decreases BP (in part due to less renin release) - b1 - bronchoconstriction - b2 - local vasoconstriction - b2 - decreased production of aqueous humor - impaired recovery from hypoglycemia - b2 - increased VLDL and decreased HDL
28
Indication of beta blockers
``` Hypertension Angina pectoris Supraventricular tachyarrhythmias CHF after AMI Hypertrophic obstructive cardiomyopathy Hyperthyroidism Pheochromocytoma Portal hypertension Esophageal varicose Glaucoma Performance anxiety Migraine Essential tremor Proliferating hemangioma (newborn) ```
29
Adverse effect of beta blockers
``` Bronchoconstriction Cardiac decompensation Bradycardia Decreased AV conduction Cold extremities Worsening peripheral vascular disease Uterus contraction in pregnancy Hypoglycemia Hyperlipidemia Increased potassium levels Sleep disturbance Depression ``` Abrupt discontinuation can give increased risk of ischemic heart disease
30
Lipid solubility of beta blockers
High lipid solubility: - propranolol - nebivolol Low lipid solubility - atenolol - sotalol - acebutolol
31
Action of beta blockers on ion channels
Weak LA effect (Na+ channel block): - propranolol - pindolol - metoprolol - acebutolol Block k+ channel - sotalol - antiarrhythmic drug (I and II)
32
Beta blockers with additional vasodilator effect (3rd gen)
Block of a1 - labetalol - carvediol NO- mediated relaxation - nebivolol - antihypertensive indication
33
Half-life beta blockers
``` Ultra-short acting 1. esmolol — b1 selective — 10 min half life — critically ill patients ``` Long half life 1. Nadolol - 16-20h 2. Betaxolol- 14-20h 3. Bisoprolol- 10-12 h 4. Nebivolol - 10 h
34
Alpha receptor antagonists
- selective a1 receptor antagonist - non-selective a receptor antagonist — synthetic compound: phenoxybenzamine and phentoamine, (tolazoline) — ergot alkaloids
35
Therapeutic interest of a receptor antagonist
Smooth muscle relaxation Antihypertensive action Peripheral vascular disease Benign prostate hyperplasia Selective a1 antagonists cause less tachycardia than the non-selective ones.
36
A2 receptor agonist
Sympatholytic effects due to negative feedback on autoreceptor - clonidine - guanabenz - Guanfacine - moxinidine - rilmenidine - methyldopa - dexamedetomidine - sedation - tizanidine - centrally acting muscle relax - apraclonidine, brimonidine - glaucoma
37
Clonidine
A2 receptor agonist - Sympatholytic effects due to negative feedback on autoreceptor - imidazoline derivative - moa: enhances negative feedback on presynaptic a2 autoreceptors, stimulates postsynaptic a2 receptors in medulla (BP regulation) and stimulates imidazoline 1 receptors in the medulla. - indication: HT (acute, mild to moderate), alcohol and opioid withdrawal, peri anesthetic medication, sedation and analgesia in ICU, diarrhea in DM, ADHD, glaucoma Adverse effects; sedation, dry mouth, bradycardia, orthostatic hypotension, mental depression. Abrupt withdrawal can cause HT crisis and increased sympathetic activity
38
Guanabenz and guanfacine
A2 receptor agonist - Sympatholytic effects due to negative feedback on autoreceptor - centrally acting antihypertensive drugs - clonidine like action but different structure
39
Moxonidine and rilmenidine
A2 receptor agonist - Sympatholytic effects due to negative feedback on autoreceptor - newer imidazoline derivatives with clonidine like structure - more sensitive to imidazoline receptor 1 in adrenal medulla - less affinity to a2? - indication: HT - sedation and dry mouth occurs less frequently than with clonidine
40
Methyldopa
A2 receptor agonist - Sympatholytic effects due to negative feedback on autoreceptor - false substrate is FOPA-decarboxylase - methylNE= a2 agonist - slow onset of action - indication: mild to moderate HT, and HT in pregnancy - adverse effects: sedation, dry mouth, hyperprolactinenia, extrapyrimidal symptoms, depression, +Coombs test, immune hemolysis, liver toxicity
41
Selective a1 receptor antagonists
``` Prazosin Terazosin Doxazosin Alfuzosin Tamsulozin Silodosin Urapidil Labetalol Carvediol ```
42
Non-selective alpha blockers
Phenoxybenzamine Phentolamine Tolazoline
43
Prazosin
Selective a1 receptor antagonist Indication: chronic treatment of mild to moderate HT, and BPH - orally active - short half life: 3x/day - side effects; first dose phenomenon (HT and syncope) - start treatment at bed time to avoid, mild and non-spesific: dizziness, palpitations
44
Terazosin and dixazosin
Selective a1 receptor antagonist - prazosin like with longer half life - indication; HT and BPH
45
Alfuzosin, tamsulosin, and silodosin
Selective a1 receptor antagonist - urinary tract - BPH
46
Urapidil
Selective a1 receptor antagonist - weak a2 agonist, 5-HT1a agonist, and beta antagonistic action - hypertensive crisis
47
Labetalol and carvediol
Selective a1 receptor antagonist. Also beta antagonist
48
Phenoxybenzamine
Non-selective synthetic alpha blocker - irreversible a blocker, long duration (14-18h) - indication: pheochromocytoma
49
Phentolamine and tolazoline
Non-selective synthetic alpha blockers - reversible a blocker - strong - pheochromocytoma (diagnosis and treat) Tolazoline - weak, vasodilation
50
Ergot alkaloids groups
- produced by fungus: claviceps purpurea - lysergic acid derivatives (LSD) - 2 major families of natural compounds 1. Amine alkaloids - ergometrine 2. Peptide alkaloids - ergotamine - ergocryptine - ergocrystine - ergocornine Agonist, partial agonist or antagonist action on several receptors, especially a and 5-HT and D
51
Main effect of ergot alkaloids
Vasoconstriction Vasospasm Powerful stimulation of pregnant uterus CNS action
52
Structurally related drugs if ergot alkaloids
Dihydro-derivatives: more selective for a receptors (antagonist) Methysergid: more selective for 5-HT receptor (antagonist) Bromocryptine, cabergoline; more selective for D receptors (agonist) Lysergic acid diethylamine(LSD); peripheral agonist on5-HT in CNS
53
Therapeutic indication of ergot alkaloids
Postpartum hemorrhage - ergometrine, ergotamine - never before delivery Migraine - ergotamine
54
Therapeutic indication of ergot derivatives
Hyperprolactinemia - bromocryptine - cabergoline Parkinson’s - bromocryptine, cabergoline Migraine - dihydro ergotamine Peripheral vascular disease - dihydro- derivatives
55
Side effects of ergot alkaloids
``` Nausea Vomiting Diarrhea Prolonged vasospasm CNS disturbances ```
56
Drugs with alpha blocking side effects
1. Several (mostly tricyclic) antidepressants - amitriptyline - imipramine 2. Several antipsychotics - phenothiazines - chlorpromazine May cause HT and reflex tachycardia 3. Quinidine - antiarrhythmic drug - to rapid iv infusion may cause BP fall
57
Adrenergic neuron blockers
``` Quanethidine Debrisoquine Bretylium Reserpine Tetrabenazine Methyltyrosine ```
58
Quanethidine and debrisoquine
- adrenergic neuron blockers - inhibit NE release from synaptic nerve terminals - antihypertensive indication - adverse effects; postural HT, diarrhea, impaired ejaculation, sodium and water retention, nasal stiffness
59
Bretylium
- adrenergic neuron blockers - inhibit release of ne from synaptic nerve terminals - blocks potassium channels on the heart - antiarrhythmic indication - adverse effects: initial release of ne can precipitate arrhythmia, sympatholytic action
60
Reserpine
- adrenergic neuron blockers - blocks the uptake of biogenic amines into the synaptic vesicles, they are not stored in the vesicles, broken down by MAO - enters the brain - depletion of me, dopamine, serotonin in both several and peripheral neurons - theoretical indication; HT And psychosis - side effects: sympatholytic action, mental depression, Parkinsonism
61
Tetrabenazine
Adrenergic neuron blockers Huntington Tourette
62
Methyltyrosine
Block the norepinephrine synthesis Adrenergic neuron blocker
63
Chronic ergot poisoning
``` Hallucinations Convulsions Prolonged vasospasm Gangrene Burning pain Abortion in pregnancy ```

Pharmacology (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions