Clinical Uses of Drugs Altering the ANS

Question 1

what are some muscarinic agonists?

Answer 1

• pilocarpine: used to treat glaucoma and dry mouth, used in sweat tests
• bethanecol: used to occasionally aid bladder and gastric emptying

Question 2

what are examples of some nicotine agonists?

Answer 2

-succinylcholine: is a high affinity agonist used in surgery for depolarising paralysis

Question 3

what are cholinesterase inhibitors and what are some examples?

Answer 3

-they inhibit the break down of Ach so there is an increase in [Ach] so there is a greater stimulation of AchRs

• there are short lasting or long lasting (parathion insecticide)
• tacrine, donezepil, rivastigmine: used for dementia, neuromuscular diseases

Question 4

when are muscarinic blockers/antagonists used?

Answer 4

• in premedication before anaesthesia: to decrease secretions and to sedate
• in the heart: to increase AV conduction
• to cure motion sickness

Question 5

when are nicotinic blockers/antagonists used and what are some examples?

Answer 5

• muscle relaxants are direct nAchR blockers: tubocurarine

- depolarising blockers are direct nAchR agonists: suxamethonium

Question 6

what are adrenoreceptor agonists used for?

Answer 6

• eye drops: ephedrine are βa blockers
• prolongation of local anaesthetic action: adrenaline
• nasal decongestation: ephedrine
• asthma inhalers: salbutamol are β2 agonists
• premature labour: they are β agonists

Question 7

what are the main uses of βa receptor blockers?

Answer 7

• for the heart: atenolol slows down HR which improves profusion, reduces the demands dn reduces arrhythmia
• in kidneys: atenolol triggers the JGA mechanism

Question 8

what are the main used of αa receptor blockers?

Answer 8

• to reduce high BP: prazosin

- to increase urination: αa1 selective

Question 9

what is prazosin more commonly used for?

Answer 9

• for male urinary problems: benign prostate hyperplasia
• the prostate gland enlarges which narrows the urethra
• this causes for the development of weak, slow urinary stream
• straining to urinate, dribbling at end, inability to empty bladder completely, uncontrollable need to void
• blocking tha α1a receptors causes relaxation of SM in bladder neck, urethra and prostrate gland

Question 10

talk about he generation of α-a blockers used to treat prostatic hyperplasia

Answer 10

• 1st + 2nd gen: (prazosin + terazosin) orally taken once a day, but side effects include low BP, wooziness and dizziness
• 3rd gen: (tamsulosin) is uroselective and have minimal effects on BP but experience ejaculatory dysfunction
• 4th gen: (alfuzosin) has comparable efficacy as 3rd gen but no effect of ejaculation

Question 11

how do drugs have an indirect enhancement of endogenous NA?

Answer 11

• cocaine, meth, MOA inhibitors (tranylcypromine)
• cocaine inhibits the NA uptake mechanism at the neuronal cell which increases the amount of NA interacting w receptors
• meth has a similar effect as cocaine but competed w NA for uptake and displaces NA in vesicles
• MOA inhibitors inhibit enzymes that break down NA which increases NA circulating: sympathetic overdrive