Cardiovascular ( 20% ) Flashcards
- Muscarinic agonists may produce
- a. Mydriasis
- b. Vasodilatation
- c. Uterine contraction.
- d. Bronchodilatation
- e. B and C
e) B and C
(vasodilation + uterine contraction)
M3 contracts the pregnant uterus
M3 causes NO release from vascular endothelial cells->vasodilation
Mydriasis = anticholinergics (eg atropine)
Bronchodilation is caused by beta 2 stimulation
(Muscarinic agonists cause bronchoconstriction)
- Effects of isoprenaline include:
- a. Reflex bradycardia
- b. Decreased peripheral resistance.
- c. Marked hypertension
- d. Reduced pulse pressure
- e. A and C
b) decreasd PVR
Due to beta 2 stimulation causing vasodilation
Is also a positive inotrope and chronotrope->increased CO but also increase myocardial O2 demand
Increases pulse pressure by reducing diastolic BP and increasing systolic BP
Used in bradycardia and heart block
Beta agonist only -> vasodilation through beta-2 effects and baroreceptor response to increased cardiac output
- In the eye
- a. Alpha adrenoceptors cause contraction of the circular papillary muscle
- b. Cyclospasm is a feature of organophosphate poisoning
- c. Beta agonist will reduce intraocular pressure
- d. Antipsychotic agents such as chlorpromazine have no effect on the eye
- e. Diuretics have no use in glaucoma
b. Cyclospasm is a feature of organophosphate poisoning
Causes mydriasis (dilation) and cycloplegia
Beta blockers reduced IOP
- Which agonist is not correctly paired with its adrenoceptor?
- a. Phenylephrine – alpha 1
- b. Clonidine – alpha 2
- c. Dobutamine – beta 1
- d. Procaterol – beta 2
- e. Prazosin – alpha 2.
e. Prazosin
Is a alpha-1 selective antagonist
- Regarding beta-receptor antagonist drugs the following has no local anaesthetic action:
- a. Labetalol
- b. Atenolol
- c. Metoprolol
- d. Propranolol
- e. Pindolol
b) atenolol
Metoprolol, labetalol, propranolol do
Timolol, atenolol do not.
- regarding isoprenaline
- a. it is a potent bronchodilator
- b. it is a selective beta1 agonist.
- c. it can be used in tachyarrythmias to decrease AV conduction
- d. it has negative inotropic effects.
- e. it causes peripheral vasoconstriction
a) is a potent bronchodilator
Non-selective beta agonist
Positive inotrope and chronotrope
Causes peripheral vasodilation through B2 agonism
- regarding beta blockers
- a. inhibits renin release via beta2 receptors.
- b. metoprolol has intrinsic sympathomimetic effects.
- c. all are well absorbed
- d. beta1 selective antagonists don’t cause bronchoconstriction.
- e. can treat ventricular tachycardias
Nick thinks e) can treat ventricular tachycardias
Not sure about this - dont use betablockers for VT/VF or torsades etc, only for SVTs as they slow AV conduction.
I think it is C) all well absorbed
Inhibit renin release via beta 1 receptors
Celiprolol and labetalol have intrinsic sympathomimetic effects (ie partial agonism - avoids bradycardia, bronchospasm, and change in lipids)
beta 1 selective can still cause some bronchoconstriction
- IV drug that causes tachycardia, decreases diastolic BP, dilates pupil, doesn’t affect ejaculation, decreases sweating:
- a. Beta agonist
- b. Alpha antagonist
- c. Muscarinic antagonist
- d. Nicotinic antagonist.
- e. Nicotinic agonist
c. Muscarinic antagonist
Picture of anticholinergic syndrome
Tachycardia = Must be a beta agonist / parasympathetic antagonist
Reduces diastolic BP, dilates pupil (alpha antagonist or muscarinic antagonist)
Doesnt affect ejaculation, decreases sweating (not an alpha blocker / muscarinic antagonist)
Nicotinic antagonists dont affect ejaculation or dilate pupil
- Which has pure beta agonist effects in the circulation?
- a. Adrenaline
- b. Noradrenaline
- c. Isoprenaline
c. isoprenaline
A and NA both have alpha effects
- Choose the odd one out:
- a. Muscarine
- b. Acetylcholine
- c. Hyoscine.
- d. Bethanachol
c. Hyoscine.
Anticholinergic, others are cholinomimetics
- A young patient is given a normal dose of a drug in the emergency department. He develops tachycardia, increased BP and dilated pupils. The drug is most likely to be:
a. Adrenaline
b. Atropine.
b. Atropine.
Children notoriously sensitive to atropine but it has does not affect BP
- dobutamine
a. results in ATP -> AMP
b. can decrease systemic vascular resistance/afterload
b. can decrease systemic vascular resistance/afterload
Selective beta 1 agonist
Causes increased CO and decreased PVR
- regarding propranolol
- a. is a highly selective beta receptor antagonist
- b. is poorly lipid soluble
- c. has sodium channel blocking activity
c. has sodium channel blocking activity
Non-selective beta blockade
Lipophilic so it can cross the BBB
(and is thus used to treat anxiety and tremor)
- A young man presents with dilated pupils, confusion and hyperpyrexia. Which of the following could not account for these effects
- a. Atropine
- b. Datura
- c. Morphine
c. Morphine
Constricts pupils, does not cause hyperpyrexia
Datura and atropine are anticholinergics
‘Red as a beet, dry as a bone, blind as a bat, mad as a hatter’
- pralidoxime acts to
- a. inhibit presynaptic acetylcholine release
- b. cleave organophosphates from acetylcholinesterase
- c. regenerate acetylcholine
b. cleave organophosphates from acetylcholinesterase
Regenerates AChE in cases of organophosphate poisoning by removing the phosphate molecule that is blocking the receptor
- A patient comes in staggering, agitated and hyperthermic with dilated pupils. Which is LEAST likely to be the cause?
- a. Atropine overdose
- b. Amphetamines
- c. Angels trumpet
- d. Tricyclic overdose
- e. Aspirin overdose
e) aspirin OD
Aspirin blocks the krebs cycle->anaerobic metabolism-> lactic acidosis
Atropine + Angels trumpet - anticholinergic
Amphetamine - sympathomimetic
TCA - anticholinergic, indirect NA stimulation, alpha blockade
- benztropine causes:
- a. miosis
- b. diarrhoea
- c. confusion
- d. bronchorrhoea
- e. GIT haemorrhage
c. confusion
Benztropine = antimuscarinic
Drys secretions, hyperthermia, confusion, seizures, mydriasis, tachycardia, vasoconstriction, bronchial SM relaxing and reduced secretions.
- All of the following are characteristics of propranolol EXCEPT:
- a. Lipid soluble
- b. Local anaesthetic action
- c. Half life 3-6 hours
- d. Beta sympathetic selectivity
- e. 30% bioavailability
d. Beta sympathetic selectivity
Propranolol is a non-selective beta blocker
- regarding prazosin, which is NOT true?
- a. It is a selective alpha 1 blocker
- b. It dilates arterioles only, not veins
- c. It undergoes extensive first pass metabolism
- d. Recipients may develop a positive test for anti-nuclear factor
- e. With negative feedback of noradrenaline on its own, release can still occur
b. It dilates arterioles only, not veins
Alpha-1 specific blocker
relax arterial + venous smooth muscle, improve lipids, no reflex tachy, decrease afterload/preload(CHF)
All alpha-1 and beta blockers are well absorped but have high first pass metabolism
Phentolamine is a non-selective alpha blocker and causes a reduced TPR and a rebound tachycardia. Poor oral absorption.
- dopamine
- a. has less alpha agonist effect than dobutamine.
- b. dilates the renal vascular bed by its action of beta 1 receptors.
- c. causes a profound rise in peripheral vascular resistance
- d. is inactivated by sodium bicarbonate
- e. causes vasoconstriction at all doses.
d. is inactivated by sodium bicarbonate
(inactivated in akaline solution)
-
a. Dobutamine has alpha 1 and beta 1 activity. Dopamine also has alpha agonist activity
- Dopamine D1=D2>>B>>a
- Dobutamine B1>B2>>>>a
- b. dilates the renal vascular bed by its action of D1 receptors
- c. causes a rise in peripheral vascular resistance at high doses
- e. causes Vasodilation at lower doses but starts to act on alpha receptors at higher doses (alpha agonism -> vasoconstriction)
- propranolol
- a. has no central effects
- b. can be used safely in type I respiratory failure because of its reliable beta 1 selectivity
- c. in overdose may be effectively treated by administering glucagon
- d. needs to be given in relatively large oral doses because of its poor absorption
- e. does not produce withdrawal symptoms on abrupt cessation because beta receptors do not up regulate
c) Glucagon can be used in the OD of betablockers
- a) is lipophilic and crosses the BBB so has central effects (anxiety, tremor medication)
- b) Non-selective beta blockade, but even then you cannot safely use B1 selective agents in asthmatics.
- d) like all beta blockers is well-absorbed, but has high first pass metabolism
- e) beta receptors can upregulate
- hyoscine
- a. may potentiate the anticholinergic effects of phenothiazines
- b. is well absorbed from the gastrointestinal tract
- c. readily crosses the blood brain barrier
- d. has its main effect at nicotinic receptors.
- e. produces pronounced tachycardia in therapeutic doses
b) Atropine and Hyoscine are naturally-occuring alkaloid esters and are well absorped orally
- a. Phenothiazines do not appear to have much in the way of anticholinergic effects (do have extrapyamidal, sedative, and antihistamine/antinausea effects)
- c. hyoscine (used for nausea) does cross the BBB, hyoscine butylbromide (Buscopan) does not cross the BBB
- d. Has its effect at muscarinic receptors
- e. Can cause tachycardia in overdose
- beta blockers
- a. are class III antiarrythmic drugs.
- b. are selective for beta 1 adrenoreceptors.
- c. are useful agents in acute heart failure
- d. may mask the symptoms of hypoglycaemia
- e. are particularly safe and effective in combination with verapamil
d. may mask the symptoms of hypoglycaemia
(beta stimulation gives typical warning signs of tremor and palpitations etc)
- a. are Class II antiarrhythmics
- b. Can be beta-1 or non-selective
- c. Are dangerous in acute HF due to reduced inotropy
- e. have additive effects with verapamil and cause cariodepression
- atropine
- a. causes ureter and bladder wall contraction
- b. acts by blocking adrenoceptors
- c. is an example of a surmountable blockade
- d. results in miosis
- e. causes bradycardia in a moderate to high therapeutic dose
c. is an example of a surmountable blockade
- reversible blockade of muscarinic receptors and competitive antagonist of cholinomimetics*
- Causes ureter and bladder relaxation*
- Blocks muscarinic receptors*
- Causes mydriasis*
- Brady at low doses, tachy at high doses*
- noradrenaline
- a. is more potent than salbutamol at beta 1 receptors
- b. is less potent than isoprenaline at alpha receptors
- c. antagonizes the effects of dopamine
- d. has similar potency to adrenaline at beta 1 receptors
- e. is less potent than adrenaline at alpha receptors
d. has similar potency to adrenaline at beta 1 receptors
Norad: a1=a2; B1>>B2
Adrenaline: a1=a2; B1=B2
Isoprenaline B1=B2>>>>a
Salbutamol B2>B1
Is less potent than adrenaline at B2 receptors (hence why noradrenaline is a better pressor, as less vasodilation)
- which of the following drugs utilises camp as a second messenger?
- a. Adrenaline
- b. Dopamine
- c. Milrinone
- d. Glucagons
- e. All of the above
a) all of the above
Adrenergic and dopamine receptors are GPCRs
(D1 = Gs; D2 = Gi)
Milrinone inhibits Phosphodiesterase 3, which breaks down cAMP
Glucagon receptor has 3 subunits (a, B, y) and -> adenylyl cyclase -> cAMP
- which of the following statements is incorrect?
- a. Noradrenaline and adrenaline exert beta effects at low doses and alpha effects at high doses
- b. Dobutamine exerts its actions via alpha effects
- c. Inotropic agents act ultimately by increasing intracellular calcium
- d. Dopamine exerts different effects at different doses
- e. Theophylline is a positive inotrope
b. Dobutamine exerts its actions via beta effects
B1>B2>>>>a
Increase CO, reduce TPR
- milrinone
- a. has a short half life because of rapid reuptake and breakdown intravascularly by COMT
- b. is extensively metabolized by the liver.
- c. is in the same class of drugs as dobutamine
- d. is a competitive inhibitor of phosphodiesterase.
- e. is one of the most commonly used inotropes in the intensive care setting
d. is a competitive inhibitor of phosphodiesterase.
Prevents cAMP degradation
Has 12% liver metabolism