CPT Flashcards
What effect will the i.v. rate of infusion have on plasma steady state?
It doesn’t effect it
(it will always take 4-5 half lives to reach state)
How do you work out the apparent volume of distribution?
Vd = dose/[drug in plasma]
Vd/ patient’s weight = apparent Vd
Which reactions take place in phase I and phase II drug metabolism?
Phase I - Oxidation/Reduction
Phase II - Glucuronidation & Sulfation (conjugation)
What is a reaction of both B Blockers and thiazide like diuretics?
Hypergylycaemia
Hyperlipidaemia
Which anti-hypertensive can be used to treat gestational hypertension?
Labetalol
A deficiency in CYP2D6 will have what effect on codeine?
Decreased therapeutic effect, an increased dose may be needed
(codeine is a pro drug - it’s metabolised to morphine by CYP2D6)
Does HRT increase the risk of VTE?
Yes
Which ion governs depolarisation (phase 0) in the SA node?
Calcium influx
(Na is ventricular AP not myocytes AP)
What are some of the ways amiodarone work?
K channel blocker (primary)
Ca channel blocker
B blocker (non-competitive)
Na channel blocker
What effect does flecainide have?
Increases the P-R interval
Increases the AP duration
Slows the tissue conduction during phase 0
How does digoxin work as an anti-arrhythmic?
via parasympathetic vagal tone
(blocks NA/K ATPase when used in HF)
Loperamide’s mechanism of action?
Decreases peristalsis but increases segmental contractions
Increases transit time to allow more fluid to be removed from the faeces
Lactulose MOA?
Draws fluid into the bowel (osmotic laxative)
Macrogols MOA?
Limit loss of fluid into the bowel (osmotic laxative)
Hyoscine hydrobromide MOA for motion sickness?
Blocks muscarinic ACh receptors
Blocks ACh at Central Trigger Zone via CN VIII
ADR is sedation which contributes to use of motion sickness
Cisplatin MOA?
Neurokinin 1 receptor antagonist
Prevents the action of substance P
Increases the effect of 5HT3 receptor antagonists
[CHEMO DRUG]
What effect do PPI have on warfarin and phenytoin?
PPIs inhibit CYP2C decreasing the metabolism of warfarin and phenytoin
PPI MOA?
Irreversibly inhibit the H/K ATPase pump
Inhibit 90% of acid secretion
Could mask gastro-oesophageal cancer
Which antihypertensive will exacerbate hyperkalaemia in patients taking heparin?
Spironolactone & Ramipril
(both inhibit aldosterone)
Factors needed for a chemo regimen?
BMI
Liver function
Renal function
Performance status
Warfarin MOA?
Competitively inhibits the oxidation of vit K by VKOR
(Limits the activation of factors II,VII,IX & X)
A high Minimum Alveolar Concentration (MAC) indicates what?
Volatile anaesthetic is less potent
(MAC is 50% who fail to respond to surgical stimulus)
Anaesthetic MOA?
Inhibition of NDMA glutamate receptors
Potentiate GABAa receptors
Why would use a vasoconstricting agent with a local anaesthetic?
Decrease peak plasma conc of local anaesthetic
Decrease the minimum effective dose
Increase duration of anaesthesia
Which ADP receptor antagonist binds reversibly to the P2Y12 receptor?
Ticagrelor (binds to a different site than Clopidogrel/Prasugrel)
Aspirin MOA?
Irreversibly inhibits COX-1 and decreases TXA2
(limits platelet aggregation)
GLP-1 agonist (exenatide) MOA?
Increase insulin secretion
Decrease glucagon secretion
Decrease gastric emptying (promote weight loss)
Caution when prescribing glicazide for diabetes?
Can cause weight gain
Disease modifying antirheumatic drugs should…
Be considered in combination in severe rheumatoid disease
What should you be cautious of when prescribing a TNF inhibitor (e.g. adalimumab)?
Reactivation of TB
(TNF is essential in granuloma formation)
Which prostanoids contribute to platelet aggregation?
PGI2 Inhibits platelet aggregation (I-I)
TXA2 Assists platelet aggregation (A-A)
What happens if inhaled particles are too small or too large?
Too big - deposit in the mouth/oropharynx
Too small - inhaled into alveoli and exhaled
What effect would grapefruit juice have on simvastatin?
Increase plasma conc of simvastatin
CYP3A4 is inhibited by grapefruit juice
CYP3A4 metabolises statins
Will liphophillic drugs cross the cell membrane and why?
Lipophillic drugs dissolve in the lipid membrane and penetrate the cell surface to cross membrane
What drug is given if a patient is unable to cope with a statin?
Ezetimibe (NPC1l1 inhibitor)
Flecainide MOA?
Increases action potential duration
Slows tissue conduction during phase 0
Increases PR interval
Why are insulins made as soluble preperations?
To delay absorption from injection site
Loperamide MoA?
Decreases peristalsis but increases segmental contractions
(more fluid can be removed)
Which anti-emetic is particularly useful in chemo induced N+V?
Neurokinin 1 receptor antagonist (aprepitant)
How do selegiline/rasagaline help in the management of parkinson’s?
Inhibit MAO B metabolism of dopamine
(prolongs action of L-dopa)
What are the 4 types of generalised seizure?
Tonic-clonic
Myoclonic
Absense
Atonic
