Medic_Summaries (IMS) Topic 5
Pharmacology
Pharmacology:
- Effect of chemicals on the human body
- Study of drugs/way drugs react biologically at receptor sites
- Study of drug effects/effect drug has once taken
- Considers toxic effects/therapeutics
- Pharmacodynamics:
- Specific to drug/drug class
- Interaction with cells, concentration effect, disease progression
- Pharmacokinetics:
- Non-specific/general processes
- Absorption from site of administration, onset time effect, elimination from body
Drug factors/rational prescribing considers:
- Pharmacokinetics
- Pharmacodynamics
- Cost
- Safety
Drug: natural/chemical substance/pharmaceutical preparation intended for administration to a
human/animal to diagnose/treat a disease
Medical device: any instrument/apparatus/implement/machine/appliance/implant/reagent for in
vitro use/software/material/other similar article intended for medical purpose(s)
Medical purposes:
- Diagnosis, prevention, monitoring, treatment/alleviation, compensation injury
- Investigation, replacement, modification/support of anatomy of physiological process
- Supporting/sustaining life
- Control of conception
- Disinfection of medical devices
- Information for in vitro examination of specimens derived from human body
Categories of drug names:
- Generic name: approved/official name
- Trade/brand name: proprietary name/name given by pharmaceutical producer
- Chemical name: derived from chemical structure
- Use name: categorised according to use prescribed for (antihypertensive)
- Effect name: categorisation relates to physiological response in body (painkiller)
Oral preparations:
- Tablet: compressed powder, coated (protection against stomach acid/environment)
- Capsule: solid dosage forms containing drug/fillers enclosed in gelatin shell
- Solution: active constituents (solute) dissolved in solvent
- Suspension: finely divided drug suspended in suitable vehicle
1 Adapted from Lectures at the University of Leeds Medical School
, Medic_Summaries (IMS) Topic 5
Routes of administration:
Route Advantage Disadvantage
Cannot be used for some drugs as inactivated
Oral Convenient, safe, economical (MOST COMMON)
by first pass metabolism/irritates gut
Suitable for suspensions/oily vehicle, rapid
May be painful/cause bleeding at site of
Intramuscular absorption from solution; slow/sustained
injection
absorption from suspension
Cannot be used to deliver large volumes of
Subcutaneous Suitable for suspensions/pellets
fluid; may irritate cutaneous tissue
Bypasses absorption yielding immediate effect;
Intravenous Poses more risk for toxicity
100% immediate bioavailability (all drug absorbed)
Between gums/teeth; rapidly absorbed; avoids Effective only for low doses; drugs; drugs
Buccal
first metabolism must be water- and lipid-soluble
Drug through the skin (adhesive patch); avoids Effective only for low doses of drug that are
Transdermal
first pass metabolism highly lipid-soluble
Drug particles need to be correct size;
Inhalation Localised effect
dependent on patient technique
Administration into spine theca (surrounds cord); Expert administration (doctors); may induce
Intrathecal
local/rapid effects infection/toxicity
Epidural Epidural space injection into spine; targeted effect Risk of failure/infection
Poorly lipid-soluble/not absorbed via skin/
Topical Non-invasive/easy to administer
mucous membrane; very slow absorption
Modified dose forms (modified release):
- Advantages:
- Improved patient compliance (less frequent administration)
- Reduction in incidence/severity of GIT effects
- Improved control over plasma concentrations:
- Chromic conditions improvement
- Therapeutic action overnight
- Minimise adverse reactions/high plasma concentration
- Disadvantages:
- Costs more per unit dose than conventional forms
- Unsafe over dosage if used incorrectly/failure of modified release tablet
- Rate of transit through GIT
- Variability in physiological factors (eg. GIT pH, enzymes, food etc.)
Pharmacokinetics:
- Absorption
- Distribution
- Metabolism
- Excretion
2 Adapted from Lectures at the University of Leeds Medical School
Pharmacology
Pharmacology:
- Effect of chemicals on the human body
- Study of drugs/way drugs react biologically at receptor sites
- Study of drug effects/effect drug has once taken
- Considers toxic effects/therapeutics
- Pharmacodynamics:
- Specific to drug/drug class
- Interaction with cells, concentration effect, disease progression
- Pharmacokinetics:
- Non-specific/general processes
- Absorption from site of administration, onset time effect, elimination from body
Drug factors/rational prescribing considers:
- Pharmacokinetics
- Pharmacodynamics
- Cost
- Safety
Drug: natural/chemical substance/pharmaceutical preparation intended for administration to a
human/animal to diagnose/treat a disease
Medical device: any instrument/apparatus/implement/machine/appliance/implant/reagent for in
vitro use/software/material/other similar article intended for medical purpose(s)
Medical purposes:
- Diagnosis, prevention, monitoring, treatment/alleviation, compensation injury
- Investigation, replacement, modification/support of anatomy of physiological process
- Supporting/sustaining life
- Control of conception
- Disinfection of medical devices
- Information for in vitro examination of specimens derived from human body
Categories of drug names:
- Generic name: approved/official name
- Trade/brand name: proprietary name/name given by pharmaceutical producer
- Chemical name: derived from chemical structure
- Use name: categorised according to use prescribed for (antihypertensive)
- Effect name: categorisation relates to physiological response in body (painkiller)
Oral preparations:
- Tablet: compressed powder, coated (protection against stomach acid/environment)
- Capsule: solid dosage forms containing drug/fillers enclosed in gelatin shell
- Solution: active constituents (solute) dissolved in solvent
- Suspension: finely divided drug suspended in suitable vehicle
1 Adapted from Lectures at the University of Leeds Medical School
, Medic_Summaries (IMS) Topic 5
Routes of administration:
Route Advantage Disadvantage
Cannot be used for some drugs as inactivated
Oral Convenient, safe, economical (MOST COMMON)
by first pass metabolism/irritates gut
Suitable for suspensions/oily vehicle, rapid
May be painful/cause bleeding at site of
Intramuscular absorption from solution; slow/sustained
injection
absorption from suspension
Cannot be used to deliver large volumes of
Subcutaneous Suitable for suspensions/pellets
fluid; may irritate cutaneous tissue
Bypasses absorption yielding immediate effect;
Intravenous Poses more risk for toxicity
100% immediate bioavailability (all drug absorbed)
Between gums/teeth; rapidly absorbed; avoids Effective only for low doses; drugs; drugs
Buccal
first metabolism must be water- and lipid-soluble
Drug through the skin (adhesive patch); avoids Effective only for low doses of drug that are
Transdermal
first pass metabolism highly lipid-soluble
Drug particles need to be correct size;
Inhalation Localised effect
dependent on patient technique
Administration into spine theca (surrounds cord); Expert administration (doctors); may induce
Intrathecal
local/rapid effects infection/toxicity
Epidural Epidural space injection into spine; targeted effect Risk of failure/infection
Poorly lipid-soluble/not absorbed via skin/
Topical Non-invasive/easy to administer
mucous membrane; very slow absorption
Modified dose forms (modified release):
- Advantages:
- Improved patient compliance (less frequent administration)
- Reduction in incidence/severity of GIT effects
- Improved control over plasma concentrations:
- Chromic conditions improvement
- Therapeutic action overnight
- Minimise adverse reactions/high plasma concentration
- Disadvantages:
- Costs more per unit dose than conventional forms
- Unsafe over dosage if used incorrectly/failure of modified release tablet
- Rate of transit through GIT
- Variability in physiological factors (eg. GIT pH, enzymes, food etc.)
Pharmacokinetics:
- Absorption
- Distribution
- Metabolism
- Excretion
2 Adapted from Lectures at the University of Leeds Medical School
