study guide/ block 1 Flashcards

study pharma

1
Q

Pharmacology

A

science of drugs includes physical and chemical properties and how these properties affect the body and interact with other substances

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2
Q

What are the 3 different sections of pharmacology?

A

1) Pharmacokinetics
2) Pharmacodynamics
3) Pharmacogenetics

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3
Q

What is pharmacokinetics?

A

the absorption, distribution, biotransformation and excretion of drugs and their metabolites in the body.

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4
Q

What is pharmacodynamics?

A

study of biochemical and physiological effects of the drugs and their mechanism of action.

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5
Q

What is pharmacogenetics?

A

role of genes in determining drug metabolism. due to factors involved in the processing of a drug(pharmacokinetics) or factors involved in the way that’s effects are mediated (pharmacodynamics)

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6
Q

What is a drug?

A

over the counter or natural medicines. Anything chemical that enters the body and has a physiological effect on the body

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7
Q

Drugs used for treatment may act to:

A

cure- only need to be taken for a set period. eg antibiotics
control- long term or else symptoms will occur. eg. insulin and antipsychotics.
alleviate symptoms but do not cure. eg. analgesics, antipyretics (bring down fever) and antiacids

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8
Q

Aim of pharmaceutical intervention?

A

Addresses the compromised function of the different tissues involved.

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9
Q

Chemical name (least likely to come across)

A

drugs chemical structure

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10
Q

Generic name

A

simplified chemical name which describes an active constituent of a medicine.

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11
Q

Brand/Trade name

A

commercial name under which drug is usually prescribed and sold

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12
Q

Group name

A

describes drug class or category to which the drug/s belongs. It reflects the drugs pharmacological action or therapeutic are of use.

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13
Q

what is adverse drug reactions?

A

a physiological effects that are not related to the desired drug effects. All drugs have adverse effects.
Adverse reaction may be due to a person’s own susceptibility which cannot be predicted. eg. allergy

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14
Q

What are the four categories of adverse drug reactions/effects?

A
Designated A (augmented)- predictable based on pharmacological action and dose-dependent.
B (bizarre)- not predictable and not dose-dependent.
C (continuous)
D (delayed)
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15
Q

Mode of action of a drug?

A

A mechanism by which drug exerts its effect on the body.

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16
Q

What is digitalis?

A

a drug used in treatment of cardiac arrhythmias. it can be taken as prescribed synthetic drug or in the form as natural remedy.

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17
Q

what is a drug?

A

it is a molecule that has a specific action in the body that is independent of its source- synthetic or natural.

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18
Q

Therapeutic dose

A

the smallest amount that will elicit a response and the largest dose that can be tolerated.

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19
Q

What is therepeutic index?

A

It indicates the margin of safety of a drug.
narrow index- drug has a narrow margin of safety. eg. dogoxin, warfarin, phenytoin, gentamicin
broad index- has a wide margin of safety.

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20
Q

A drug with a narrow therapeutic window is important to monitor. why?

A

Because it has a very small gap between dose that gives a therapeutic effect and a dose that elicits toxic effects. Therefore, it is important to monitor to ensure drug is having a therapeutic effect and has not caused undue toxic effects. SAFE DOSE FOR ONE PERSON MAYBE TOXIC FOR OTHERS.

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21
Q

Prescription medicines

A

Drugs that need an authorised person to prescribe them.

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22
Q

Over the counter medicines(OTC)

A

may be bought without prescription but major concern is safety issue, not complying to recommended dose. taking with prescribed meds can ofeten casue adverse drug interactions.

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23
Q

Complementary and alternative medicine (CAM)

A

therapist or treatments that are not commonly accepted in conventional medical practice. eg; herbal, vitamins, minerals, supplements.

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24
Q

Pharmacy only drugs

A

refers to medicines that may only be sold in a community or hospital pharmacy.

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25
Restricted medicine
refers to pharmacist only medicines, sold w/o prescription but sale can only be made by a registered pharmacist.
26
Five rights of drug administration
``` right drug right dose right client right route right time ```
27
Formulation and administration of drugs
Drugs can be administered orally, intravenously or by another route rectal, inhalation, IM, SC. It may be given as solid (tablet, pills, capsules, lozenges), liquid (injections, spray, suspension, emulsion), gas (O2, anaesthetics)or topical (creams, ointment and gels).
28
Drugs administered intravenous
drug will go straight into bloodstream and can be delivered to its site for drug action to occur. faster onset of drug action
29
Drugs administered orally.
has to go through GI tract and across the membranes before it enters the bloodstream. Longer for the drugs to take effect
30
Pharmacokinetics
the way the body acts on the drugs once its been administered to the body.
31
Four process of pharmacokinetics
absorption, distribution, metabolism and excretion. it all involves movement across membranes. 1)into blood from side of administration 2) once in blood it must cross membranes to reach site of action 3) cross membranes to undergo metabolism and excretion
32
Lipid soluble drugs
they cross membranes easily unlike other drugs that must dissolve directly into lipid bilayer of the membrane before passing
33
Pharmacokinetics absorption process
1) most drugs cross membranes by passive diffusion (high to low concentration) but some drugs needs a carrier mediated transport. eg: levodopa 2) small molecule will diffuse more rapidly than large molecules 3) lipid soluble nonionised drugs are absorbed faster 4) absorption is affected by blood flow, pain, stress...
34
Plasma protein binding
most drugs travel in the plasma partly in solution in the plasma water and partly bound to plasma proteins. ratio varies between drugs Binding is reversible. Bound drug is inactive. Only unbound drug can cross membranes. Acidic drugs bind to albumin Basic drugs bind to a1-acid glycoprotein
35
adverse reactions: Type A
extension of pharmacological effect. dose dependent. often predictable. responsible for at least 2/3 ADRs- dry mouth, blurred vision, constipation
36
movement across membranes
passive dif- from high to low concentration until equilibrium is reached active dif- requires a carrier mediated transport. eg levadopa-parkinson's
37
absorption
movement of a drug from its site of administration into the blood things that affect absorption of drug- route, drug characteristics, transit time, blood flow, surface area, pain
38
distribution | -protein binding can be affected by drugs-eg bilirubin
movement of a drug throughout the body
39
metabolism | main organ-liver
chemical modification of drug phase I- oxidation/reduction & hydrolysis phase II- conjugation
40
excretion
unchanged drug or metabolite removed from body.most drugs are ecreted in the urine
41
what is prodrug?
inert when enters the body & has to be activated. eg simvastatin
42
first pass effect/metabolism | -where drug reaches the liver first
warfarin/morphine do not go into systemic circulation but pass from intestinal lumen to the liver but some drugs dont go directly into systemic circulation
43
distribution-plasma protein binding
- most drugs travel in the plasma partly in solution in the plasma water & partly bound to plasma proteins - binding is reversible. - bound drug is inactive and only unbound drugs can cross membranes
44
what drugs binds to albumin?
acidic drugs
45
what binds to a1-acid glycoprotein?
basic drugs
46
examples of drugs extensively bound to protein 90%+
warfarin, diazepam, phenytoin, quinidine
47
drugs less extensively bound to proteins
digoxin, theophylline, gentamicin, metformin.
48
Diseased state
can cause problems in effectiveness of drug
49
Pt has liver cirrhosis-decreased albumin made.how will it affect the drugs that are distributed in the body bound to albumin?
liver function is compromised therefore less albumin is being made. the drugs bound to albumin will have less albumin to bins to and so more drugs will be unbound and therefore able to cross membranes
50
what effect will acidic drugs bound to albumin have
these drugs will have a greater effect on the pt with cirrhosis than on a pt with normal liver. therefore pt with cirrhosis will have greater chance of having adverse effect because of more 'free drug' in their systemic circulation. it will have toxic effect rather than therapeutic effect
51
what is the action for this?
be aware of the dosage and reduction of dosage may be needed
52
what is involve in metabolising drugs?
making a drug polar and water soluble for easy excretion by the kidney
53
what does drugs have to be before they can be excreted?
must be biotransformed or metabolised
54
phenytoin
stimulate liver synthesis metabolising enzyme
55
cimetidine
inhibit liver (hepatic) metabolising enzymes
56
what is bioavailability?
% of administered drug dose that reaches systemic circulation
57
drug half-life
amount of time required for plasma concentration of a drug to decrease by 50% after discontinuance of the drug
58
example of half life of drug- 4 hrs
``` initially-100% after 4 hrs- 50% 8 hrs- 25% 12 hrs- 12.5% 16hrs- 6.25% ```
59
ways in which drugs work MOA
drug can work-chemical reaction drug can act-physical action what drugs bind to cause effect-binding to a receptor
60
what are receptors?
dif types. usually part of a cell either on surface or within giving rise to the drugs adverse effects. usually a protein
61
what is an agonist ?
drugs that bind to a receptor and produce a response in the cell eg, insulin will bind to insulin receptor to mimic action of the hormone that is naturally produce in the body-for people with T1DM, unable to make their own insulin
62
what is an antagonist?
drugs bind to receptors but blocks a response hence stop the biochemical or physiological response from being stimulated
63
drug receptor interaction
binding with specific receptors occurs only when the drug and its receptors have a compatible chemical shape
64
other reasons for adverse effects
- genetic - drug action can work too well - drug not selective & binds to other types of receptors
65
Non-steroidal anti-inflammatory drugs
stops the synthesis of prostaglandin by blocking the enzyme needed
66
Nucleotide analogue Reverse transcriptase inhibitors (NRTI)-
works specially by blocking the action of the reverse transcriptase enzyme which is only present in viruses like HIV
67
Monoamine oxidase inhibitors (MOI)
used for depression & stops the enzyme monoamine oxidase from breaking noradrenaline down.^ level= good wellbeing feeling
68
what is individual variation?
one person ca response to the same drug dif to another person. drug therapy must be tailored to suit each person
69
factors involved in individual variation? - pathological status-liver/kidney disease - placebo effect
- age- neonate-elderly decreased metabolism - body weight - genetics - gender - tolerance- decreased responsiveness= repeated drug administration
70
what is placebo effect?
component of drug response that is caused by the psychological factors
71
drug interaction | pharmacodynamics
often predictable from actions of interacting drugs
72
drug interaction | pharmacokinetics
affect absorption and distribution metabolism and renal excretion of the drug
73
drug-drug interactions | drug a & drug b
A could intensify the effects of drug B- potentiation A could reduce the effect of B- inhibitory A and B combined could result in dif drug response
74
potentiative effects may result in what?
increased therapeutic effects or increased adverse effects.
75
inhibitory effects may result in?
reduced therapeutic effects or reduced adverse effects.
76
drug drug interaction means
the greater number of dif drugs a person is taking the greater risk of detrimental interaction
77
drug food interactions
- food can decrease rate of drug absorption eg. grapefruit can inhibit - metabolism of certain drugs - may increase drug toxicity - may affect drug action
78
timing of drug administration with food
if drugs absorption is increased in presence of food. therefore administer with meals
79
timing of drug administration without food
if drugs absorption is decreased in presence of food therefore administer 1 hr before meal or 2 hrs after meal
80
what is contraindication?
where a condition or factors means that the use of the meds should be contraindications, prec/warnngs and interactions
81
what is warning/precautions?
where the benefits of using meds may outweigh the risks but need to be assessed and may need to be closely monitored
82
what is onset of action?
time it takes to reach minimum effective concentration MEC after drug administration
83
what is peak of action?
occurs when drug reaches its highest blood or plasma concentration
84
what is duration of action?
the length of time the drug has pharmacological effects.
85
how long till drugs produce effects?
may effect in minutes and some in hours or days
86
What would happen if the drug plasma/serum levels drop below MEC?
If the drug does not reach MEC then this means it will not be effective in treating the condition.
87
What would happen if the drug plasma/serum go above maximum toxic concentration (MTC)?
If the drug goes above MTC then it is now in toxic levels in the body, which can be very dangerous.
88
vulnerable groups and drug therapy
includes very young children, elderly and pregnant women.
89
very young
due to organ immaturity
90
elderly
due to organ system degeneration
91
pregnant women
due to physiological changes of the pregnant women's body
92
paediatrics | pharmacokinetics
covers all patient under 16.
93
paediatrics administration of drugs
majority of drugs administered to adults are also useful to children BUT the dosages are dif.
94
paediatrics pharmacokinetics -absorption
- slowed gastric and peristalsis. - reduced gastric acidity - poor peripheral tissue perfusion - decreased skeletal muscle mass.
95
paediatrics pharmacokinetics -distribution
- higher body water/fat ratio than adults - lipid membranes are more permeable especially blood/brain barrier - protein binding will be reduced
96
paediatrics pharmacokinetics -metabolism
- reduced in neonates - liver takes 3 yrs to mature - metabolism may be greater in older children than adults. therefore a higher dose may be needed to obtain therapeutic effect
97
paediatrics pharmacokinetics excretion
- kidney takes 1 yr to mature - older children have renal function similar to adults - neonates have decreased GFR and tubular excretion thus decreased clearance of drugs
98
paediatrics | pharmacodynamics
- some drugs reduced effects in neonates eg.digoxin | - some drugs increased effects in neonates eg. CNS depressants
99
doses in neonates and children
calculate based on age or weight
100
Why is relying on age alone for calculation of drug dose not the best means for children?
Relying on weight alone for calculation of dose is not good because differences in maturation and organ development is not taken into account.
101
elderly drug reactions
more common in elderly due to increased used of drugs (polypharmacy). increases risks of drug interactions
102
elderly drug reactions | -altered pharmacokinetics
- absorption is slower. - distribution is altered - elimination of drugs reduced - liver metabolism is reduced
103
elderly drug reactions | -altered pharmacodynamics
- prolonged activity, leading to possible problems with toxicity - less sensitivity to some drugs
104
elderly drug reactions | -disease state
-may influence response to drugs -e.g. patients with rheumatoid arthritis may be more prone to suffer gastrointestinal bleed after NSAIDs. -Congestive heart disease – reduced blood flow.
105
elderly drug reactions | -homeostatic mechanisms
-become increasingly impaired and may lead to postural hypotension due to reduction of normal reflex
106
Pharmacokinetics in the pregnant mother may be altered because:
absorption- GI motility is slowed which increases absorption of poorly soluble drugs eg digoxin
107
Pharmacokinetics in the pregnant mother may be altered because: -Compensatory changes in drug dosage may be needed
distribution- plasma volume and extracellular fluid increased up to 50% causing haemodilution -albumin decreases so with acidic drugs mean more free drugs avail bsic drugs means lower levels of free drugs
108
what is haemodilution?
it reduces plasma concentration of drugs
109
Drugs and Pregnancy
Drugs may cross the placenta and affect the foetus, therefore only take drugs if absolutely necessary. This includes OTC and life style drugs.
110
Drugs and Lactation
Drugs may affect the baby via breast milk, as most drugs can enter breast milk.
111
Drugs taken by the breast-feeding mother may
- Affect milk production - Get into the milk in high enough dose to affect the infant - Nearly all drugs can enter breast milk BUT some [e.g. lipid soluble] will enter more easily.
112
use of metoclopramide or | domperidone in breastfeeding
Some drugs can be used to increase milk supply if required.
113
Examples of Drugs to be Avoided during Pregnancy
- alcohol - all ACE inhibitors - anticonvulsants - tetracycline - lithium - warfarin - some anticancer drugs
114
Examples of Drugs to be Avoided during breast feeding
- cocaine/heroin - ergotamine - lithium - benzodiazepines/barbiturates - some antithyroid drugs - bromocriptine - sulphonamides