Module 1- Pharmacology Flashcards

1
Q

Define pharmacology

A

The study of drugs- divided into pharmacokinetics and pharmacodynamics

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2
Q

What are the characteristics of drugs

A

Potency
Selectivity
Specificity

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3
Q

Define potency

A

The amount of chemical required to produce an effect

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4
Q

Define selectivity

A

The narrowness of a drug’s range of action on a receptor

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5
Q

Define specificity

A

Refers to the range of action of a drug and the relationship between the chemical structure and its pharmacological action (e.g. beta blockers)

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6
Q

How are drugs identified

A

By 3 names- chemical, generic (or approved) and trade (or proprietary)

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7
Q

What is a chemical drug name

A

A precise description of the drug’s chemical composition and molecular structure

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8
Q

What is a generic drug name

A

Determined by the manufacturer and approved by the local drug regulating authority – it’s official name e.g. paracetamol, ibuprofen

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9
Q

What is a trade drug name

A

The name the company uses to advertise the drug e.g. nurofen, panadol

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10
Q

What are drug schedules and which relate to medications

A

Outline different classifications of poisons

2, 3, 4 and 8 pertain to medications

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11
Q

Explain drug schedule 2

A

Labelled Pharmacy Medicine
Only available to public from pharmacies or person licensed to sell schedule 2 poisons
Examples: cough and cold preparations, worm tablets, antihistamines, anti-inflammatory agents

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12
Q

Explain drug schedule 3

A

Labelled Pharmacy Medicine
Only available from pharmacist or medicinal/dental practitioner but without need for prescription. Storage not accessible to public
Examples: adrenaline injections, topical corticosteroids and asthma aerosols, emergency contraception

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13
Q

Explain drug schedule 4

A

Labelled Prescription Only Medicine
Needs prescription from doctor or dentist and must be stored in dispensary
Limited range can be given by some qualified nurses, optometrists and podiatrists
Examples: antibiotics, antidepressants, hormones

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14
Q

Explain drug schedule 8

A

Labelled controlled drugs
Can produce addiction, prescriptions only valid for 3 months. Must be kept in locked cabinet
Examples: opioids, CNS stimulants

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15
Q

List different ways drugs are classified

A
  • Source
  • Chemical formula and structure
  • Pharmacokinetic parameters
  • Activity
  • Action
  • Clinical use
  • Body system affected by the drug
  • Drug schedule
  • Pregnancy safety
  • Allowed to be used in sport competition
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16
Q

What do nurses need to know about drugs

A

Indications
Contraindications
Adverse Reactions
Dosage

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17
Q

List different drug legislation and nursing

A

Health Practitioner Regulation National Law Act 2010 (WA)
Australian Health Practitioner Regulation Agency (AHPRA) Code of Ethics for Nurses August 2008
AHPRA Code of Professional Conduct for Nurses August 2008
Poisons Act 1964 (amended 2012)
Poisons Regulations 1965 (amended 2012)

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18
Q

What is pharmacokinetics

A

Factors that affect how the body handles the drug– UTILISATION
There are 4 fundamental pharmacokinetic processes:
1. Absorption
2. Distribution
3. Metabolism
4. Elimination/excretion

Controls speed of onset of the drug, intensity of the drug effect and duration of drug action

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19
Q

Explain pharmacokinetic process: Absorption

A

Unchanged drugs are absorbed into the body fluid and transported to site of action which is determined by the route of administration
Occurs via two processes:
1. Passive transport-diffusion: the passive (no energy required) transfer of a drug from a region of high concentration to a region of lower concentration
2. Carrier-mediated transport: requires an energy source and involves active transportation with the movement of a drug molecule from areas of low concentration to areas of high concentration

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20
Q

Explain factors that affect nature of absorption

A

Blood flow- rich supply enhances (IV=immediate)
Solubility- more soluble= faster absorption
Ionisation- ionised water-soluble do not diffuse readily through membranes, un-ionised lipid-soluble can cross membrane
Formulation of drug- can be manipulated to achieve desirable absorption e.g. adding resin to slow absorption

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21
Q

What is absorption determined by

A

The size and surface area of the absorbing site

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22
Q

Explain pharmacokinetic process: Distribution

A

Process of reversible transfer of a drug between the bloodstream and the extracellular fluid and/or cells of tissues
On entry into circulatory system, free drug molecules bind to proteins to form drug-protein complexes which decreases the free drug concentration and limits tissue distribution
As free drug is removed from the circulation, the protein-drug complex dissociates so that more free drug is released (high conc. to low conc.)
Only free/unbound drug exerts pharmacological effects

23
Q

What does distribution depend on

A

Blood flow- tissues with high blood supply such as brain, heart and kidneys = faster
Capillary permeability
Binding of drugs to proteins

24
Q

List barriers to distribution process

A
  1. Blood-brain allows only lipid-soluble drugs e.g. general anaesthesia, into the brain and CSF
  2. Placental membrane separating blood vessels of mother and foetus. Enzymes in placenta can metabolise some agents making them inactive. Barrier is impermeable to lipid-soluble and water-soluble drugs allowing them to cross the barrier. Can have a therapeutic effect on mother but exert harmful effects on developing embryo
25
Q

Explain pharmacokinetic process: Metabolism

A

Process of chemical modification of a drug and is mostly carried out by enzymes
Major drug metabolising enzymes are CYTOCHROME P450 and UDP-GLUCURONOSYLTRANSFERASES (UGT)
The liver is the primary site for metabolism, other sites include kidneys, lungs and intestinal mucosa
Differences between individuals rates of metabolism is due to genetic, environmental, age and disease-related factors

26
Q

What is bio-availability

A

The proportion of drug administered that reaches the systemic circulation intact which is determined by:

  1. Amount of drug absorbed from the GI tract
  2. Amount of drug escaping extraction (first-pass metabolism) by the liver (called first-pass effect)
27
Q

Define biotransformation

A

Occurs in the liver where enzymes react and breakdown the drugs - metabolites are then transported to their site of action

28
Q

Explain pharmacokinetic process: Elimination

A

Also called excretion
To be eliminated from the body drugs must be converted to form that can be eliminated by kidneys Applies to loss of unchanged drug or metabolite via urine or bile

29
Q

Explain renal excretion

A

Occurs via 3 processes: filtration, secretion and re-absorption
The acidity and alkalinity of a drug can affect excretion. Alkaline drugs are excreted quicker in acidic urine and acidic drugs are excreted quicker in alkaline urine

30
Q

Explain biliary excretion

A

After liver metabolism, drug metabolites may be transported into the bile, passed into the duodenum and excreted in the faeces

31
Q

Explain pulmonary excretion

A

Drugs such as general anesthetics are inhaled and excreted via the lungs

32
Q

Explain sweat and saliva excretion

A

A slow and minor process. Drug metabolites in sweat may contribute to skin conditions and reactions

33
Q

Explain excretion in breast milk

A

Many drugs and their metabolites cross the epithelium of the mammary glands and are excreted in breast milk.
Exposure depends on the mother’s plasma drug concentration and amount of milk ingested by the infant

34
Q

List the different routes of administration

A

Enteral/Oral
Topical
Parental
Wafer (sublingual- part of parental)

35
Q

Define pharmacodynamics

A

What the drug does to the body, its actions and effects – ACTION and REACTION
Influenced by pharmacokinetic factors
Drugs that bind to receptors are termed agonist and antagonists

36
Q

Define agonist

A

Binds to and activates the receptor producing the same response as the endogenous ligand (growth hormone, adrenaline)

37
Q

Define antagonist

A

Binds to a receptor and blocks access of the endogenous ligand therefore diminishing normal response (anti-hypertensive medication, Beta blockers)

38
Q

Define partial agonist

A

Produce less than the maximum effect even when receptors are occupied

39
Q

How do drugs act

A

By combining with a small molecule, producing an alteration of cell membrane activity or combining with receptors
All drugs act by binding to a protein, the molecular target or site of action

40
Q

What is drug selectivity

A

Degree to which a drug acts on an active site- depends on chemical structure, molecular size and electrical charge

41
Q

What are the 4 main types of regulatory proteins that drugs can act on

A

Carriers, enzymes, ion channels and receptors

42
Q

Define adverse drug reaction

A

Any response to a drug which is noxious, unintended and occurs at doses normally and appropriately used for prophylaxis, diagnosis or therapy of disease

43
Q

Define drug allergy

A

Hypersensitivity to any drug and is characterised by previous exposure to either the same or a chemically related drug and then produces clinical manifestations of an allergic reaction

44
Q

Define side effect

A

A drug effect that may not be the primary purpose for giving the drug in a particular condition (are known responses) e.g. nausea

45
Q

Define therapeutic range

A

Reflects the range of drug concentrations having a high probability of producing the desired therapeutic effect and low probability of producing adverse effects

46
Q

Define therapeutic index

A

Ratio between toxic (harmful levels) and therapeutic concentrations of the blood. If something has a low therapeutic index the ratio between therapeutic concentration and toxic levels is very small, which can be hazardous as even small over doses could produce harmful effects

47
Q

Define plasma concentration

A

The measurement of the concentration of the drug in a sample of blood plasma

48
Q

What are the key pharmacokinetic parameters

A

Clearance
Volume of distribution
Half-life

49
Q

Define clearance

A

Determines the maintenance dose required to achieve the target plasma concentration at a steady state (keep within therapeutic range)

50
Q

Define volume of distribution

A

The volume in which the drug in the body would need to be distributed to produce the observed concentration of the drug in the blood

51
Q

Define loading dose

A

The initial amount of drug required to fill the volume of distribution

52
Q

Define half-life

A

Affected by volume of distribution and clearance
How long it takes to reduce to 50% of its original concentration in the blood stream (e.g. how long does it take to go from 100mL to 50mL)

53
Q

How can drugs affect developing fetus

A

Some drugs that have therapeutic effect on mother, can act as teratogen, mutagen or carcinogen
Foetus’ have immature livers

54
Q

How does ageing affect pharmacokinetics

A

Pharmacokinetics are altered in aging due to reduced gastric acid and slow gastric motility, resulting in unpredictable rates of dissolution and absorption of drugs