Top 100 Drugs

Question 1

In Benign prostatic enlargement, what are the 1st and 2nd line treatments usually?

Answer 1

1st line - a-blockers

2nd line - 5a-reductase inhibitors

Question 2

How do 5a-reductase inhibitors work?

Answer 2

Improve lower urinary tract symptoms and reduce the need for prostate related surgery

Question 3

How do 5a-reductase inhibitors work?

Answer 3

Reduce the size of the prostate gland by inhibiting the intracellular enzyme 5a-reductase

Question 4

S/E 5a reductase inhibitors

Answer 4

Related to their androgen action - impotence, reduced libido, breast tenderness/gynaecomastia, hair growth, breast cancer (in finasteride)

Question 5

Example of common 5a reductase inhibitor

Answer 5

Finasteride

Question 6

What can a-blockers be used for?

Answer 6

1st line Tx for BPE when conservative management doesnt work
An add on Tx for resistant HTN

Question 7

What does a-blockers cause?

Answer 7

Vasodilation and a fall in BP

Reduced resistance to bladder outflow

Question 8

Examples of common a-blockers

Answer 8

Doxazosin
Tamsulosin
Alfuzosin

Question 9

S/E a-blockers

Answer 9

Postural hypotension
Dizziness
Syncope
(Particularly common after 1st dose)

Question 10

Who should a-blockers not be used in?

Answer 10

Patients with already existing postural hypotension

Question 11

What can acetylcholinesterase inhibitors be used for?

Answer 11

Mild to moderate Alzheimers disease

Mild to moderate dementia in Parkinsons disease (Rivastigmine)

Question 12

What is acetylcholine?

Answer 12

An important CNS neurotransmitter

Question 13

How do acetylcholinesterase inhibitors work?

Answer 13

Inhibt cholinesterase enzymes that break down acetylcholine in the CNS - increasing the amount of acetylcholine available for neurotrasmitting - improving cognitive function and reducing the rate of cognitive decline

Question 14

S/E acetylecholinesterase inhibitors

Answer 14

N + V + D (from increased acetylecholinesterase activity in PNS)
Exacerbation of asthma or COPD symptoms
Less common - peptic ulcers + bleeding, bradycardia, heart block
Hallucinations / aggressive behaviour
Small risk of extrapyramidal symptoms and neuroepileptic malignant syndrome

Question 15

Contraindications of acetylecholinesterase inhibitors

Answer 15

If taking NSAIDS/steriod therapy - increased risk of PUD
Use alongside antipsychotics may increase the risk of neuroepileptic malignant syndrome
If used alongside B blockers = bradycardia and/or heart block may occur

Question 16

Examples of acetylcholinesterase inhibitors

Answer 16

Donepezil

Rivastigmine

Question 17

What is acetylcysteine used for?

Answer 17

1. Tx for paracetomal poisoning

2. To reduce the viscosity for respiratory secretions in hosp patients

Question 18

S/E acetylcystine

Answer 18

When used IV for paracetomal poisoning - can cause an anaphylactoid reaction (like anaphylaxis)
When used nebulised as a mucolytic can cause bronchospasm

Question 19

What should be measured at presentation of paracetomal poisoning and on completion of acetylcystine Tx - and what does this track?

Answer 19

INR, ALT, creatinine

To track the trajectory of liver injury

Question 20

What can activated charcoal be used for?

Answer 20

Reduce absorption of certain poisons - only recommended within 1 hour of ingestion of a clinically significant amount of a substance that is absorbed by charcoal

Question 21

S/E activated charcoal

Answer 21

Most common - black stools + vomiting
Aspiration can lead to serious Cx - pneumonitis, bronchospasm, airway obstruction
Can precipitate IO

Question 22

What is adenosine a first line diagnostic and therapeutic agent for?

Answer 22

SVT

Question 23

How does adenosine work?

Answer 23

Increases AV node refractoriness - cardioversion

Question 24

S/E adenosine

Answer 24

Can induce bradycardia or even astystole - very unpleasant sensation for patient however only brief due to the drugs very short half life

Question 25

Contraindications of adenosine

Answer 25

Should not use if cannot tolerate the bradycardic effects e.g. hypotension, coronary ischaemia or decompensated heart failure
Avoid in asthma/COPD as can induce bronchospasm
Heart transplant

Question 26

When would adrenaline be used?

Answer 26

1. In cardiac arrest - for shockable and unshockable rhythms
2. Anaphylaxis
3. Can be used to induce local vasoconstriction by local injection e.g. in endoscopy to control mucosal bleeding and can also be mixed with local anaesthetic to prolong local anaesthesia

Question 27

How does adrenaline work?

Answer 27

Potent agonist of the a1, a2, B1, B2 adrenoreceptors and so has sympathetic effects

• vasoconstriction of vessels supplying skin, mucosa and abdo viscera
• increase in HR, force of contraction, myocardial excitability
• vasodilation of vessels supplying heart and muscles
• bronchodilation and suppression of inflammatory mediator release from mast cells

Question 28

S/E adrenaline

Answer 28

In cardiac arrest - adrenaline induced HTN
Anxiety, tremor, headache, palpitations
Angina, MI, arrhythmias