autonomic nervous system part 2

Question 1

list down the actions of adrenergic drugs

Answer 1

heart
reduce refactory period increase automaticity of sa node and latent pacemakers av node and purkinjee fibres certain anaesthetics like chlorofrom and halothane contribute to arrythmic action
cardiac actions beta 1 mediated
blood vessels beta 2 mediated vasodilation alpha 1 and 2 mediated vasoconstriction
bp: na causes rise in systolic and diastolic bp as no b1 vasoldilatory action iso and adr cause marked rise in systolic bp but fall in diastolic bp
respiration : iso and adr are bronchodilators
mydriasis occurs due to radial muscles of iris contraction
relaxes gut, peristalsis is reduced detrusor muscle in bladder contracts
increases neuromuscular transmission
adr produces glycogenolysis, hyperlactacaemia reduction of insulin no major cns effects but stimulation of alpha 1 receptor causes bradycardia.

Question 2

list down adverse effects of adregenic drugs

Answer 2

transient restlessness, palpitation ,anxiety, tremor ,

marked rise in bp may lea to ventricular tachycardia, cerebral haemorhhage, myocardial infarction

Question 3

contractindication of adregenic drugs

Answer 3

adr is contraindiacted in hypertensive, hyperthyroid, amgina

Question 4

therapeutic classification of adrenergic drugs

Answer 4

pressor agents noradrenaline, ephedrine, dopamine
cardiac stimulants dobutamine
bronchodilators salbutamol, isoprenaline
nasal decongestants phenylephrine
cns stimulant amphetamine
anorectics sibutramine
uterine relaxant and vasodilators salbutamol

Question 5

write uses of dobutamine, dopamine ,ephedrine, amphetamine , phenylephrine

Answer 5

dopamine d1 receptors are more sensitive in renal mesentric blood increase gfr and na plus excretion raises systolic bp and no effect on diastolic bp increases cardiac output, useful in cardiogenic shock and septic shock
dobutamine : cardiac output increased , short term management of severe congestive heart failure
ephedrine: used in mild bronchial asthama and for hypotension during spinal ansesthesia , it crosses the brain and causes stimuation
amphetamine : orally active with long duration causes alertness, longers atttention span euphoria postponement of sleep deprivation, hunger is inhibited by supression of feeding centre in the hypothalmus

Question 6

phenylepinephrine

Answer 6

it is used as nasal decongesant (alpha agonist) for causing mydriasis also raises bp by vasoconstriction

Question 7

adrenergic alpha blocker 
phenoxybenzamine, 
ergot alkaloids 
phentolamine
prazosin
tamsulosin

Answer 7

phenoxybenzamine: intermediate reacts with alpha adrenoreceptor
the alpha blockade develops gradually
it tends to shift blood from extravascular to vascular compartment because of relaxation of precapillary and post-capillary vessels phenoxybenzamine is lipid soluble and penetrates into the brain causes stimulation nausea vomiting used in septic shock and peripheral vascular disease.
ergot alkaloids used in migraine
phentolamine: rapidly acting alpha blocker used for intraoperative management of pheochromocytoma , hypertension.
prazosin: alpha 1 : alpha 2 selectivity 1000:1 it blocks sympathetically mediated vasocontriction produces fall in bp, postural hypotension
prazosin is used as an anti hypertensive , prostatic hypertrophy blocks alpha 1 receptors improves urine flow , reduces residual urine bladder
tamsulosin: is uroselective due to higher affinity to alpha receptor that dominate in urinary bladder no specific cardivascular affetcs no signifiant changes in bp or
dizziness and retrograde ejaculation are the only noted adverse effects

Question 8

uses of alpha blocker

Answer 8

pheochromocytoma: the syndrome in which the adrenal medullary cells excess CAs ( catecholamines) which cause persistent hypertension phenoxybenzamine is genreally used for as a definitive therapy for inoperable malignant tumours it is also employed before and during surgical removal of the tumour

Question 9

therapeutic classification of beta blocker

Question 10

uses of beta blockers