Pharmacology Flashcards
1
Q
Pharmacodynamics vs pharmacokinetics
A
Pharmacodynamics: drug action and mechanism
Pharmacokinetics: absorption, distribution, metabolism, excretion
2
Q
Drug absorption
A
- Lipid-soluble, polar, ionised drugs pass easily through membranes
- Water-soluble, non-polar, non-ionised drugs have more difficulty
- Free molecules can pass through capillary walls, whereas bound are too large
- Most drugs move across membranes by diffusion (passive transport)
- Drugs absorbed rapidly where high blood flow
3
Q
Drug distribution
A
- Factors influencing distribution:
- increased blood flow to tissue
- exiting vasculature
- BBB –> only allows lipid-soluble drugs
- placental barrier –> non-selective
- adipose tissue acts as reservoir for lipid-soluble drugs
- enterohepatic cycling –> GI tract –> portal vein –> liver –> excrete into bile –> small intestine
4
Q
Drug metabolism
A
- drug alteration by cytochrome P450 enzymes
- increases water solubility for excretion
LIVER PHASE 1: functionalisation - chemical reactions increase water solubility
LIVER PHASE 2: conjugation - metabolite joins with polar substance - drug doses calculated on First Pass Effect
- factors affecting metabolism: genetic, environment, disease, age, drug interactions, % bound
5
Q
Drug excretion
A
- Kidneys, biliary excretion, respiratory expiration, sweat, saliva, breast milk
- Kidney - via 3 processes
1. Glomerular filtration
2. Passive tubular reabsorption (lipid-soluble)
3. Active tubular secretion (water-soluble, polar, ionised)
6
Q
Loading dose
A
- amount given to reach minimum effective concentration (usually 2x normal dose)
- maintenance dose given after
7
Q
Dose-response curves (eg. morphine)
A
- relationship between size of administered dose and intensity of response produced
- margin of safety between analgesic effect and respiratory depressive effect
8
Q
Efficacy
A
- index of the maximal response a drug can produce
- height of dose-response curve
9
Q
Potency
A
- Index of how much drug must be administered to elicit a desired response
- same effect with lower dose = more potent
10
Q
Therapeutic index
A
- Measure of drug safety
- high TI = more safe drug
- TI = lethal dose/effective dose
11
Q
Factors contributing to medication errors
A
- Poor labelling
- miscommunication
- lack of verification (9 rights)
- incomplete prescriptions
- inadequate staffing
- disorganised medications
- interruptions
12
Q
9 rights of medication administration
A
- Right patient
- Right drug
- Right dose
- Right route
- Right time
- Right indication
- Right documentation
- Right response
- Right action
13
Q
VTE prophylaxis
A
- Pharmacological - eg. Rivaroxaban (anticoagulant)
* Non-pharmacological - eg. TED (thrombo-embolus deterrent) compression stockings
14
Q
INR
A
- International Normalised Ratio
- How long it takes blood to form a clot
- normally ~1
- might aim for 2-4 for someone on warfarin
15
Q
Drug Schedules
A
Schedule 2: pharmacy medicine Schedule 3: pharmacy only medicine Schedule 4: prescription medicine Schedule 5: caution Schedule 6: poisons Schedule 7: dangerous poisons Schedule 8: controlled drugs Schedule 9: prohibited substances Schedule 10: substances of such danger to health to warrant prohibition
16
Q
Schedule 2 drugs
A
- pharmacy
- eg. antihistamines, paracetamol
- may be RN/midwife initiated
17
Q
Schedule 3 drugs
A
- pharmacy only
- eg. salbutamol
- requires pharmacist advice
- may be RN/midwife initiated
18
Q
Schedule 4 drugs
A
- prescription only medicine
- eg. antihypertensives, antibiotics, sleeping tablets
19
Q
Schedule 8
A
- controlled drug
- eg. morphine, pethidine
- supply, storage, prescription, and disposal are controlled by law
20
Q
Schedule 9 drugs
A
- prohibited substances
- eg. heroin, MDMA, cannabis
- usage restricted to analytical labs and trials
21
Q
Schedule 11 drugs
A
- drugs of dependence
- eg. tramadol, temazepam
- S4 and S8 medications with potential for abuse
22
Q
High risk drugs
A
Antibiotics Potassium Insulin Narcotics Chemotherapy Heparin & anticoagulants System (requires extra processes)
23
Q
Who can check schedule 8 drugs out of a safe?
A
Under Victorian law, one RN must check a schedule 8 drug out of a safe
24
Q
Bioavailability refers to:
A
The amount of drug that reaches the systemic circulation
25
First Pass Effect
Phenomenon whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation, particularly when administered orally, due to the fraction lost by absorption and metabolism by the liver, in the stomach.
