Intro to pharmacology - route of admn & basics Flashcards

1
Q

Pharmacokinetics - what is it ? … mechanism ?

A

What the body does to the drug
- absorption
-distribution
-metabolism
-excretion

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2
Q

Pharmcodynamics

A

what drug does to the body
includes : mechanism action + effect of the drug

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3
Q

what constituets pharmcotherapy

A

prevention
treatment
diagnosis

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4
Q

What are the principles in drug administration

A

Safety
Rationalizing
montioring
individualizing

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5
Q

What is rationalisation of drug? & principles

A

drugs given match the clinical need
dosage must meet the individuls requirement
for an adequate period of time
at low cost for both community & patient
(effectiveness, safety, and cost-effectiveness of various drugs to make informed decisions about their use.)

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6
Q

Effects of irrational prescription

A

Delay in cure
More adverse effects
loss patients confidence
Lowering health standards

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7
Q

Causes of irrational prescription

A

Underprescribing - not enough dosage
Incorrect prescribing
Over prescribing

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8
Q

How to choose best way to treat a condition?

A

-is drug therapy indicated ? and if so
-which drug is best for condition?
-which route is most effective ?
-which formulation ? capsule , rectum , serum
-Which dosage regimen? - during the night , after meals , day , how many times in a day.

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9
Q

What is P-drug ( personal drug)

A

Drug that you have become familiar with and choose to prescribe regulary.
- all categories of drugs there is a p-drug (prototype drug)

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10
Q

Advantages of P-drugs

A

Convinent
confidence
master easily
predictable
less complications
simpler healthcare management

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11
Q

What are the major classification of routes of drug administration

A

Enteral
Paraenteral
Topical

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12
Q

Describe Enteral & give examples

A

Def : delivery of drug through GIT(then absorbed) from the mouth
Example : oral , sublingual , rectal

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13
Q

Define Parenteral & give examples

A

Def : delivery of drug directly into body through IV
Example:
- intravenous/intraarterial
- subcutaneous
- Intramuscular
- intradermally

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14
Q

Define topical and give examples

A

Def: apply the drug directly onto the surface of skin / mucous membranes - allowing for local action of drug on the specific area applied
Examples
- Nasal(spray) , auditory(drops) , mucosal , conjunctival
- Vaginal & urethral
- Inunction (ointment , cream ) & dermal

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15
Q

What are facotrs that govern the route of drug administration ?

A

1.Physical & chemical properties of drug
2.Rate & extent of absorption
3.effects of digestive juices - can it withstand
4.site of desired action
5.rapidity of desired response
6.accuracy of dosage
7.condition of patient - child cannot swallow tablets

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16
Q

Advantages & disadvantages of Oral

A

Adv
1.Safe
2.Convenient
3.Economical
4.Usually good absorption
5.self administered
6.Painless

Disadv
1.Slow absorption
2.slow action
3.irritable & unpalatable(not pleasant) - can spit it
4.some drugs destroyed
5.First - pass effect

17
Q

Sublingual
-Location
-Advantages & Disadvantages

A

Site : under the tongue
Adv
1.Economical
2.Drug absorption quick - dissolved & absorbed directly in circulation
3.First pass avoided
4. self administered
5.quick termination - spit off

Disadvantages
1.Unpalatable & bitter drugs
2.Irritation of oral mucosa ( cause mouth ulcers)
3. Large quantities not given
4. High molecular weight drugs not absorbed - due to small spaces itd have to pass through

18
Q

Example of drugs administered sublingually (systemic & local)

A

Systemic use
- Isosorbide dinitrate
- nitroglycerine
- Nifedipine

Local
- antiseptic lozenge

19
Q

Advantages & Disadvantages of Rectal route

A

Advantages
1. Used in children
2. Little/no first pass effect (avoids 50%) - majority of drug absorbed
3. Used in vomiting /unconsious
4.Higher conc can be given
5.Can use gastric irritants

Disadvantages
1. embarrasing
2.inconvient
3.Absorption is slow & erratic
4. Irritation/ inflammation of rectal mucosa

20
Q

Examples of drugs given via rectal route . ( local & systemic)

A

Local
1.Dulcolax
2.Glycerine suppository
3.Enema - dissolve in oral mucosa
4.Ointment

Systemic
1.Aminophylline
2.Indomethacin suppositories

21
Q

Intradermal route
- Site
- advs & disadvantages
- example

A

Site : outer layer of skin
Adv
1.Used for testing sensitivity to drugs
2.high vascularity of dermis

Disadv
1.Painful
2.Amount of drug administered is small
3. Slow adsorption
4.Skin irritation

Example : BCG vaccine , allergic sensitivity test ,tubercullin test
uses tuberculin syringe 4

22
Q

Subcutaneous

A

Site: under skin ( deeper than intradermal)
Sites : gluteal , thigh , shoulder , back

Advs
1.Smooth but slow absorption
2.Depot injections , implants

Disadvantages
1.only Small vol (1ml )
2.irritant drugs = lead to necrosis
3. not suitbale in shock (vasoconstriction + redistibution of blood)

23
Q

Examples for subcutaneous route

A

Local : local anaesthetic
Systemic: insulin

24
Q

intramuscular
major sites
advantages & disadvantages

A

Major sites : deltoid , gluteus , vastus lateralis

Advantages
1.absorption reasonably uniform
2. rapid onset action
3. mild irritants can be given
4. first pass avoided
4.Gastric factors can be avoided

DIsadvantages
1. only up to 10ml given
2.local pain & abscess
3.Expensive
4.Infection
5.Nerve damage (sciatic nerve )

25
Q

Intravenous route advantages

A

1.Bypass first pass metabolism (100%)
2.quick onset of action
3.unccoperative & unconsoiious patients .vomiting & nausea
4. drugs of hypertonic solns & irritants
5.LArge volumes
6.Amount of drug can be controlled accurately

26
Q

Disadvantages of intravenous

A
  1. Required antiseptic conditions - to prevent infection in blood
  2. specialised skills
    3.painful
  3. cannot be recalled - wrong dosage is a wrong one
  4. cause air embolism - lead e.g heart failure , pulmonary embolism
  5. cannot give suspensions , oily drugs & depots
  6. can cause extravastion / thrombophlebitis
27
Q

What is extravasation

A

escape of fluid from a blood vessel to surrounding tissue during IV cannulisation
- painful & harmful

28
Q

Definition of Thrombophlebitis

A

irritation of vein during cannulation causing inflammation and leading to clot.

29
Q

Intra-arterial
Site
advantage
Disadvantage
example

A

Site: lumen artery
Advantage:
-greater conc of drug can be delivered

Disadvantage
-Expertise
-Asepsis

Example : radiopaque contrast for coronary angiopraphy & cerebral angiography

30
Q

Intraperitoneal
Site
Advantages & Disadvantages
Examples

A

Site : peritoneal space
Advantages
- rapid absorption (due to large SA)

Disadvantages
- Painful
- risky
- adhesions
-peritonitis

example: dialysing fluid ( renal failure)

31
Q

Intrathecal(intraspinal)
Site
Advantages & disadvantages
Example

A

Site: subarachnoid space
Advantages
- bypass Blood brain barrier

Disadvantages
- asepsis
- expertise
- painful
- risky

Example : radiopague contrast media , xylocaine injection

32
Q

Intramedullary
Site
Advantages & Disadvantages
Examples

A

Site : tibia
Advantages : rapid onset of action
Disadvantages
- strict asepctic conditions
- expertise
- painful
- risky

Examples : Emergency fluids in children

33
Q

Intracardiac injection
site
Examples

A

Left 4th intercostal space into heart muscle
Example : cardiac arrest

34
Q

Intraarticular route
site
advantages & disadvantages
Example

A

Site: directly into joint space
Advantages: high conc in localised area
DIsdavantages:
- asepsis
- joint damage
- pain

Example :
- Hydrocortisone
- Gold chloride

35
Q

Transdermal route
what ?
advantages

A

what? absorption of drug through skin for systemic action via a patch

Advantages
1. stable blood levels - ( a particular mg permin)
2. no first pass metabolism

Disadvantages
3. drug must be potent or patch will become too large

potent meaning - administered effectively through a transdermal patch, the drug needs to be highly concentrated or potent. this is because, in a transdermal patch, the drug is absorbed through the skin over an extended period. If the drug is not potent, it would need to be present in large quantities in the patch to achieve the desired therapeutic effect, which would result in a very large or bulky patch.

36
Q

What is first pass effect

A

term used for hepatic metabolism of drug when it is absorbed from gut & delivered to liver via portal circulation
The greater the first pass effect , the lower the bioavailability of the drug