Pharmacology Flashcards

1
Q

What is pharmacology

A

Study of drug action on the body

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2
Q

What is pharmacokinetics

A

The study of what the body does to a drug

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3
Q

What is pharmacodynamics

A

Physiological effects of a drug on the body

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4
Q

What does ADME mean in pharmacokinetics

A

Absorption
Distribution
Metabolism
Excretion

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5
Q

If a drug is given orally, where does it go

A

GI tract

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6
Q

What happens when a drug is absorbed by the GI tract

A

Goes to the liver where some drugs are broken down

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7
Q

How can elimination happen

A

Broken down by liver
Excreted by kidneys
Excreted via lungs

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8
Q

Where does pharmacological action happen

A

Circulation tissue space

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9
Q

What is absorption

A

Rate and extent at which a drug leaves its site of administration and enters the circulatory system

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10
Q

What can impede the efficacy of a drug

A

Route of administration e.g. orally or rectally

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11
Q

What can enhance or impair the rate of absorption

A

Presence of food

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12
Q

What happens when the GI tract is compromised

A

A parenteral route must be considered

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13
Q

Why does location of drug administration need to be considered

A

Tissue perfusion will also impact on absorption

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14
Q

What is first pass effect

A

When a drug has been absorbed into circulation it is transported to the liver via hepatic portal system where it is metabolised

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15
Q

Why do we have to reduce the amount of active drug being distributed within the body

A

Because some drugs undergo extensive hepatic metabolism

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16
Q

What is produced by first pass effect

A

Drug and metabolites

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17
Q

How can first pass effect be avoided

A

Using parenteral route which bypasses this process and provides body with a more accurate dosage

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18
Q

Once a drug has been metabolised by the liver, where does it go

A

Enters the systemic circulation and travels in the plasma to its site of action

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19
Q

What happens once a drug has reached the desired site of action

A

It leave the plasma and enters interstitial fluid then the cells and combines cellular receptors to create an action

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20
Q

What affects drug distribution

A

Drug formulation
Blood flow to that area
Binding/unbinding of the drug to plasma proteins
Presence of anatomic barriers

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21
Q

What are fat loving drugs

A

Lipophilic

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22
Q

What are water loving drugs

A

Hydrophilic

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23
Q

Which route of administration is best for hydrophilic drugs

A

IV, IM as they enter the extra cellular fluid

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24
Q

Which route of administration is best for lipophilic drugs

A

Orally or SC as needs rap diffuse through a cell membrane

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25
Q

When are drugs most rapidly distributed. Give examples

A

When entering well perfused tootsies e.g. active skeletal muscle, liver, kidney, brain

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26
Q

Which tissues are poorly perfused

A

Inactive skeletal muscle and adipose fats

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27
Q

What remains in the circulation as a reservoir for circulating drugs

A

Plasma proteins

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28
Q

What happens when a drug binds with a plasma protein (albumin)

A

Termed inactive and unable to migrate into the tissues to exert its effect

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29
Q

What happens to drugs that do not bind to plasma proteins

A

Able to migrate into tissues and exert effect

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30
Q

What happens to the amount of unbound and bound drug after plasma protein binding

A

Drug within circulation will remain the same

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31
Q

What happens to bound molecules when unbound drug molecules move into tissues during plasma protein binding

A

Bound molecules are released to maintain the balance

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32
Q

Why is protein binding significant

A

Because plasma protein levels are reduced due to disease as the standard dose could cause toxic concentrations

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33
Q

Which organs can cause toxic concentrations of drugs

A

Liver, GI, kidney

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34
Q

Why are anatomical barriers important

A

In the capillaries of the CNS as endothelial cells in the brain are closely packed together preventing some drugs from entering

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35
Q

What type of drugs can cross the blood:brain barrier

A

Lipophilic

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36
Q

What happens to drugs before they can be excreted

A

Biotransformation / drug metabolism

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37
Q

Where does bio transformation happen

A

Generally in liver (lungs and kidneys)

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38
Q

What happens when drugs are metabolised

A

Enzymes modify the molecules of the drug to enable elimination

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39
Q

What does enzyme action do during metabolism

A

Provokes chemical reactions that cause drug to become hydrophilic enabling drug to be eliminated by kidneys

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40
Q

Factors affecting drug metabolism

A

Species, age, nutritional status, health status

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41
Q

Where does excretion take place

A

Liver, lungs, skin, glands e.g. mammary, sweat and salivary

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42
Q

Why does excretion route need to be taken into consideration

A

Could compromise effectiveness of excretion when specific organ is diseased

43
Q

Why is pharmacokinetics important

A

Formulates suitable drug dose and dosing regime to facilitate therapeutic effect

44
Q

Pharmacokinetic parameters:

A

Bioavailability
Volume of distribution
Clearance and half life

45
Q

What is bioavailability

A

The quantity of the administered drug reaching systemic circulation

46
Q

When is bioavailability reduced greatly from 100% IV

A

When given orally

47
Q

What is volume of distribution

A

Measurement relating to the amount of drug absorbed within the plasma, body tissues and cells

48
Q

What properties of a drug affect a drugs ability to distribute

A

Interaction with plasma proteins, drug for me.g, hydrophilic or lipophilic

49
Q

What is clearance

A

Volume of blood cleared of a drug from eliminating organ e.g. liver, kidneys

50
Q

What is important when devising a drug regime for a patient regarding clearance

A

To enable suitable serum drug concentrations. Must be equal to the rate of drug administration

51
Q

What is half life

A

Time it takes for drug to be reduced by 50% at current concentration level

52
Q

What can greatly affect the plasma concentration of a drug

A

Efficacy of kidneys and liver as half life will take longer to decrease

53
Q

Why is pharmacodynamics important

A

Ensured indication for using specific drug has been discussed and any contraindications have been evaluated

54
Q

What to cellular receptors normally interact with regarding drug-receptor interaction

A

Endogenous Ligands

55
Q

What are endogenous ligands

A

Natural substances e.g hormones and neurotransmitters

56
Q

How does a drug exert its effect

A

By binding to a protein receptor found in the cell membrane, cytoplasm or nucleus

57
Q

What is affinity

A

Ability of a drug to bind to receptor

58
Q

What is efficacy

A

Ability of a drug to produce the desired effect

59
Q

What is an agonist

A

Drug that has good affinity and efficacy

60
Q

What is an antagonist

A

Drug that has poor affinity and efficacy

61
Q

What is the therapeutic effect

A

Effect of a drug within an Animals body to control a specific disease or manage physiological function. The narrow dosage parameter a drug has to remain in, to enable therapeutic effect to be efficient

62
Q

What happens when therapeutic range is too high

A

May produce toxic effect. MSC: maximum safe concentration or MTC: minimum toxic concentration

63
Q

What happens when the therapeutic range is too low

A

Prevents the desired effect and termed minimum effective concentration (MEC)

64
Q

How long does a prescription last for

A

6 months for normals drugs. Can be on repeat

28 days for controlled drug. Cannot be on repeat

65
Q

Requirements for POM-V

A

Once prescribed by VS who is confident the person using it is competent to do so.

Drug will have safety issues or concerns, deemed that specialist knowledge is required, drug has narrow safety margins and is government policy

66
Q

Requirements for POM-VPS

A

Registered qualified person e.g. vs, pharmacist or SQP. Prior clinical assessment is not prerequisite

67
Q

Requirements for POM-V (CD)

A

Dispensed once prescribed by VS
Drug access must be by person deemed confident by vs to handle
VS will have key

68
Q

Pros for oral administration of medication for owners

A

Easy for most owners

69
Q

Cons for oral administration of medication

A

Slow compared to parenteral
Not suitable for unconscious/vomiting patient
Food can impact on administration
Can cause irritation (V/D)
Gastric acid can denature drugs
Liver enzymes may break down drugs before it reaches systemic circulation

70
Q

Pros of parenteral administration of medication

A

Directly into systemic circulation therefore 100% bioavailability
Drug action achieved quickly
Drugs can irritate skin

71
Q

Cons of parenteral administration of medication

A
Requires asepsis
Must be solution 
Must be given slowly
Irritant drugs can cause severe tissue damage 
Catheter care
72
Q

Pros of IM administration of medication

A

Can be suspended drug

Absorbed quicker than SC

73
Q

Cons of IM medication administration

A

small volumes at a time
2ml in cats
5ml in Dogs

74
Q

Pros of SC administration of medication

A

Can be large amounts of fluid

Generally pain free

75
Q

Cons of SC medication administration

A

Multiple sites should be used for high volumes of fluid to avoid discomfort
Possible damage to small blood vessels
Local reaction to drug can occur

76
Q

Where do you admin IM injections and how long does it take

A

Quadriceps of hindlimb takes 20-30 minutes

77
Q

How long does SC injection take to work

A

30-45 minutes

78
Q

What is intaosseous

A

Injection into bone marrow in medulla of long bone; when IV is compromised e.g. birds

79
Q

What is epidural

A

Aseptic technique of injecting into vertebral canal outside the duramater

80
Q

What is intrarthecal

A

Aseptic technique of injection into subarachnoid space containing cerebrospinal fluid; contrast media for myelography

81
Q

Subconjunctiva

A

Into conjunctival membrane of eye

82
Q

Legal requirements to f dispensing label for medication

A
  • Name and address of animal and owner
  • Name and address of approved premises supplying the medication
  • Date of supply
  • The words ‘keep out of reach of children’
  • The words ‘for animal treatment only’
83
Q

Discuss the cascade system

A
  1. Veterinary medicinal produce authorised in the UK for another condition in the same species or another species with the same condition
  2. Medicinal product authorised in uk for human use or veterinary product authorised in eu member state for use in animal species
  3. Veterinary product made by vs, pharmacologist or person holding manufacturers authorisation as prescribed by vs
84
Q

Key information given to clients when dispensing medication

A
  • Technique demonstration e.g. using pill guns, filling syringes and tube feeding.
  • Specific requirements for drug e.g. before food
  • Potential side effects/contraindications and client told to phone if this happens
  • Told when to stop medication and told to return an medication if necessary
  • Person dispensing should be confident client is happy doing what is expected
85
Q

Requisition requirements for schedule 2 drugs

A

Made in writing to supplier, signed by vs

86
Q

Storage requirements for schedule 2 drugs

A

Locked cabinet secured to wall or floor
Destruction must take place in front of authorised person
Invoices kept for 2 years

87
Q

Dispensing requirements for schedule 2 drugs

A

Drug register kept with all purchases and each supply within 24 hours

88
Q

Requisition requirements for schedule 3 drugs

A

Made in writing to supplier, signed by vs (same as schedule 2)

89
Q

Schedule 2 drugs

A

Morphine
Pethidine
Fentanyl
Ketamine

90
Q

Storage requirements for schedule 3 drugs

A

Locked cabinet

Invoices kept for 2 years (same as schedule 2)

91
Q

Dispensing requirements for schedule 3 drugs

A

No register

92
Q

Examples of schedule 3 drugs

A

Pentobarbital
Phenobarbital
Buprenorphine
Tamazepam

93
Q

Requisition requirements for schedule 4 drugs

A

Prescription bed by MRCVS

94
Q

Storage requirements for schedule 4 drugs

A

None

95
Q

Dispensing requirements for schedule 4 drugs

A

Prescribed by MRCVS but should be checked. Can be dispensed by SQP/vet/nurse as long as checked

96
Q

Examples of schedule 4 drugs

A

Benzodiazepines

Anabolic steroid

97
Q

Examples of schedule 5 drugs

A

Coedine

Morphine (in less than specified amounts)

98
Q

What does p.o or per os mean

A

By mouth

99
Q

What does a.c mean

A

Before food

100
Q

What does p.c mean

A

After food

101
Q

What does q. Mean

A

Every

102
Q

What does p.r.n mean

A

As necessary

103
Q

What does a.s mean

A

Sufficient quantity