Top 100 Drugs Flashcards
In Benign prostatic enlargement, what are the 1st and 2nd line treatments usually?
1st line - a-blockers
2nd line - 5a-reductase inhibitors
How do 5a-reductase inhibitors work?
Improve lower urinary tract symptoms and reduce the need for prostate related surgery
How do 5a-reductase inhibitors work?
Reduce the size of the prostate gland by inhibiting the intracellular enzyme 5a-reductase
S/E 5a reductase inhibitors
Related to their androgen action - impotence, reduced libido, breast tenderness/gynaecomastia, hair growth, breast cancer (in finasteride)
Example of common 5a reductase inhibitor
Finasteride
What can a-blockers be used for?
1st line Tx for BPE when conservative management doesnt work
An add on Tx for resistant HTN
What does a-blockers cause?
Vasodilation and a fall in BP
Reduced resistance to bladder outflow
Examples of common a-blockers
Doxazosin
Tamsulosin
Alfuzosin
S/E a-blockers
Postural hypotension
Dizziness
Syncope
(Particularly common after 1st dose)
Who should a-blockers not be used in?
Patients with already existing postural hypotension
What can acetylcholinesterase inhibitors be used for?
Mild to moderate Alzheimers disease
Mild to moderate dementia in Parkinsons disease (Rivastigmine)
What is acetylcholine?
An important CNS neurotransmitter
How do acetylcholinesterase inhibitors work?
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
S/E acetylecholinesterase inhibitors
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
Contraindications of acetylecholinesterase inhibitors
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
Examples of acetylcholinesterase inhibitors
Donepezil
Rivastigmine
What is acetylcysteine used for?
- Tx for paracetomal poisoning
2. To reduce the viscosity for respiratory secretions in hosp patients
S/E acetylcystine
When used IV for paracetomal poisoning - can cause an anaphylactoid reaction (like anaphylaxis)
When used nebulised as a mucolytic can cause bronchospasm
What should be measured at presentation of paracetomal poisoning and on completion of acetylcystine Tx - and what does this track?
INR, ALT, creatinine
To track the trajectory of liver injury
What can activated charcoal be used for?
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
S/E activated charcoal
Most common - black stools + vomiting
Aspiration can lead to serious Cx - pneumonitis, bronchospasm, airway obstruction
Can precipitate IO
What is adenosine a first line diagnostic and therapeutic agent for?
SVT
How does adenosine work?
Increases AV node refractoriness - cardioversion
S/E adenosine
Can induce bradycardia or even astystole - very unpleasant sensation for patient however only brief due to the drugs very short half life
Contraindications of adenosine
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
When would adrenaline be used?
- In cardiac arrest - for shockable and unshockable rhythms
- Anaphylaxis
- 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
How does adrenaline work?
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
S/E adrenaline
In cardiac arrest - adrenaline induced HTN
Anxiety, tremor, headache, palpitations
Angina, MI, arrhythmias
