Pharmacology Flashcards
What are the four stages of pharmacokinetics
Absorption
Distribution
Metabolism
Excretion
How does albumin binding affect distribution
How does blood flow affect distribution
More albumin bound- harder to distribute
More blood flow= better distribution
What is the definition of volume of distribution
How does molecular weight affect this
What does volume of distribution help calculate
The theoretical volume the drug would have to occupy to equate to plasma concentration
Higher molecular weight- more likely to be protein bound therefore less volume of distribution
Dosing (larger vD needs bigger dose to get concentration)
What is bioavailability
What is it normally in IV drugs
How do you calculate bioavailability
The amount of unchanged drug reaching the circulation
100%
AUC (oral)/ AUC (IV) x100
Elimination
What is the difference between first and zero order kinetics
First- a constant proportion of the drug is excreted in time. Depends on the concentration in the body.
Zero order- a constant amount is excreted over time. Not dependant on concentration
How do you calculate half life
Volume of distribution/clearance
How many half lives does it take to get to steady state
To prevent toxicity what do you want the steady state to do?
How can you achieve steady state more rapidly?
Which pharmacology principle contributes most to steady state
4-5
Be within therapeutic range
Loading doses
Clearance
What type of drugs need to be metabolised by the liver before they can be Renally excreted?
What are the three processes in phase 1. What enzymes do they need
Lipophillic
Oxidation, reduction and hydrolysis
Cytochrome p450
What are the two most common cytochrome p450s
Which is needed in codeine. What does a low analgesic response mean
CYP1A2
CYP34A4
CYP206- poor metabolism
What are examples of p450 inducers. Give 5 p450 inhibitors
Phenobarbitone/ phenytoin, carbamazepine, alcohol, ridampicin, St. John’s wort
Grapefruit, erythromycin, cipro, cotrimox, amiodarone
What are examples of processes seen in phase 2 liver metabolism
Acetylation, sulphination, glutathione production and glucuronidation
What defines antibiotic tolerance
MBC>4x MIC
What is the most important mechanism of the following antibiotics
Beta lactams
Aminoglycosides
Vancomycin
Give an example of a bacteriostatic antibiotic
MIC
Concentration dependant killing
Time dependent killing
Trimethoprim
Which chemo acts on the following cell cycles G1 S G2 m
G1 asparginase and prednisone
S methotrexate and 6MCP
g2 etoposide and bleomycin
M vincristine and vinblastane
Which chemo causes radiation recall
Which causes extravasation injuries
Daunorubicin
Vincristine and doxyrubicin
Which 2 chemo cause vomiting ++
Cisplatin
Cytarabine
Which chemo causes fever
Cytarabine (araC)
Which chemo causes anaphylaxis
Asparginase
Which chemo causes pancreatitis
Asparginase
Which antibiotic acts on the cell wall directly
Vancomycin
Which antibiotics act on protein synthesis and how
Gent and tetracyclines- 30s
Macrolides and clinda- 50s
Which antibiotics act on DNA synthesis and how
DNA gyrase- cipro
Folate- trimethoprim
RNA- rifampicin
1mg pred= how much hydrocortisone
1mg dex=‘
4mg
25mg
What are the main side effects of
Cyclosporine
Tacrolimus
Hirsuitism and gum hypertrophy
Alopecia, diabetes and low mg
What does a clockwise hysteresis loop show? Anti-clockwise?
Tachyphylaxis
Delayed distribution
How do the following diabetes meds work
Metformin
Glicazide
Thiazolinedinedones
Increased sensitivity
Increased production
Increased sensitivity
What MABs work on the following Terminal complement pathway Cd20 Interferon alpha Il 1 Il6 IgE
Ecilizumab Rituximab Infliximab/adalimumab Anakinara Tocilizumab Omalizumab
What is the main mechanism of omeprazole
Serotonin antagonist
What are the main side effects of Rifampicin Isoniazid Ethambutol Pyrazinamide
Orange secretions and liver toxicity
Peripheral neuropathy and liver toxic
Hepatitis esp with isoniazid
Reduced colour vision
What are the main side effects of the following AEDS
Vigabatrin
Topirimate
Ethosuximide
Behaviours and ocular toxicity
Renal stones and weight loss
GI
AED side effects Keppra Sodium valproate Lamotrigine Carbamazepine
Behavioural change and weight gain
Pancreatitis low plt weight gain
GI, liver and pancytopenia
Liver and SJS
Which chemo causes bad constipation
Vincristine
Which two chemos cause secondary malignancies
Cyclophosphamide
Etoposide
What are the three main steps in treatment of hyperkalaemia and what does each step do
1) give gluconate- stabilises the myocardium
2) give insulin/dextrose- moves it all intracellular
3) give resonium- reduces total body potassium
How does MMF work
What are the three main side effects
Blocks purine synthesis
Stops proliferation of b and T cells
Diarrhoea vomiting and renal
How does methotrexate work
What are the main side effect
What is a serious but rare side effect
Anti folate- reduces TNF alpha
Ulcers mood changes
Hepatitis
What is the main cause of liver toxicity in paracetamol overdose
Conversion by CYP450 to NAPQI
