PHARMACOLOGY ppt 1S PRELIM.SECONDYEAR NURSING. OUCH REVIEW NANAMAN.pdf

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1. PHARMACOLOGY

2. PHARMACOLOGY
From the word pharmakon, the Greek word of drug – is the study of drugs ( substances
that produce changes in the body and characterization of their;
Structure, targets and mechanism of action
Distribution I and handling the body
Effects on the body, including desirable responses ( Efficacy) and undesirable side –
effects( toxicity)

3. PHARMACOLGY
•Can be studied at multiple ways:
•1. Clinical pharmacologist – is the study of drugs in human pt.
•2. Toxicology – is the study of harmful rather than therapeutic effects.
•3. Pharmacy – involves manufacturer, preparations and dispensing of drugs
•Nurses deal with pharmacotherapeutic or clinical pharmacology, the branch of
pharmacology that uses drugs to treat, prevent and diagnose diseases.
•Clinical pharmacology addresses two key concerns : the drugs effects on the body and
body’s response to the body.

4. DRUGS SOURCES
PLANTS – the leaves, roots, bulb, stem, seeds buds and bloosoms.
- isolating and intensifying the active components.
Example; Digitalis and morphine

ANIMALS – body fluids, glands or insulin, enzymes pepsin and vaccine
Examples: Hormones, Anti toxic serum, gamma globulin from human blood

5. DRUGS SOURCES
MINERALS – Occur in nature or are combined with other ingredients.
Example; Iron, iodine, Zinc oxide and magnesium sulfate
SYNTHETIC - is the artificial building up of a chemical compound by the union of its
elements. Drugs such as epinephrine that were once available only from natural
sources can now be artificially reproduced through synthesis. Other drugs such as the
sulfonamides were originally created through synthesis.
Microorganisms. Chemical substances produced by microorganisms such as fungi
and bacteria are also sources of drugs. Examples: penicillin, tetracycline, and vaccines

6. PHARMACOKINETICS
(WHAT THE BODY DOES TO A DRUG)
Deals with a drug’ action as it move through the body
Discusses how a drug is:
ABSORBED ( taken into the body)
DISTRIBUTED (move into various tissue)
Metabolized ( change into a form that can be excreted
EXCRETED ( removal from the body)

7. PHARMACOKINETICS
•ONSET OF ACTION – Is the time it takes for the drug to reach its minimum
effectivity concentration
•PEAK EFFECT – Occurs when the drug is exerting its maximum effect and its highest
concentration.-
•DURATION OF ACTION – is effective concentration the length of time that the drug
remains above its minimum

8. PHARMACOKINETICS
PROCESS:
ABSORPTION; This covers a drug progress from the time it’s administered, through it’s
passage to the tissues, until it react to systemic circulation
✔All administration routes
( except the intravenous route) require the drug to go through absorption.

9. PHARMACOKINETICS
•Factors affecting Absorption:
✔Taking a bite – Pinocytosis is a form of active transport
• that occurs when a cell engulfs a drug particle ( vita, ADEK )
✔Watch the speed limit
-Typically, absorption – occurs with in seconds or minutes when a drug is administered
sublingual, I.V or by inhalation
✔Absorption occurs at a slower rate when drugs are administered by the oral, I.M,
subcutaneous routes

10. PHARMACOKINETICS
•Factors affecting Absorption:
✔At a snail’s pace – some drugs can take several hours or to reach peak ( rectally
administered sustain)
✔The slowest form of absorption is through the skin and mucous membrane.

•Ex. Gluta

11. PHARMACOKINETICS
•Factors affecting Absorption:
✔Not enough time – other factors can affect how quickly a drug absorbed. ( exam. A
patient who has had large sections of the small intestine surgically removed, drug
absorption is decreased)
✔Look to the Liver – Drugs absorbed by the small intestine are transported to the liver
before being circulated to the rest of the body.
✔- The liver may metabolize much of the drug before it enters the circulation.

12. PHARMACOKINETICS
✔This mechanism is referred to as the FIRST PASS EFFECT
✔It lowers the amount of active drug released in one systemic circulation.
✔Therefore , higher drug doses must be administered to achieve the desired effect.
MORE BLOOD MORE ABSORPTION
✔Increase blood flow to an absorption improves dry absorption , where as reduced blood
flow decreases absorption
✔(Deltoid is faster than gluteal )

13. PHARMACOKINETICS
•Slowed by pain and stress
✔Pain and stress can decrease the amount of absorbed because autonomic response to
drug
✔High fat doesn’t help
✔ High fat meals and solid food slow the rate at which contents leave the stomach and
enter the intestine delaying intestinal absorption of a drug

14. PHARMACOKINETICS
•DO FORM FACTORS
✔ Drugs formation ( such as tablet, capsules, liquid, sustained – release formulas) affects
the drug absorption rate.
✔ABSORPTION INCREASEDOR DECREASE?
- Combining one drug with another drug or with food can cause interaction that increase
or decrease drug absorption depending on the substances involve.

15. FIRST – PASS- EFFECT
✔ Drugs absorbed from the GI TRACT enter the liver via the hepatic portal vein and are
subjected to metabolism by the liver before reaching the main circulation.
✔This is why oral doses must be higher than intravenous ( IV ) doses which will directly
enter the blood stream with out entering the liver.

16. BIOAVAILABILITY
•Is a measure of the rate and extent of drug transfer from its administration site to the
systemic circulation
✔Intravenous injection is deemed to have the highest bioavailability ( 100% )

17. DISTRIBUTION
•Drug distribution is the process by which the drug delivered from the systemic
circulation to the body tissues and fluids

18. FACTORS AFFECTING DISTRIBUTION
•- BLOOD FLOW
✔The drug is quickly distributed to organs with large supply of blood.
SOLUBILITY
✔Depends on whether the drug is water or lipid ( fat ) soluble. Lipid soluble drug easily
a cross through cell membranes: Water soluble drug can’t.
✔Lipid soluble drugs can also cross the blood brain barrier and enter the brain.

19. FACTORS AFFECTING DISTRIBUTION
•Example for solubility:
✔A common example of this is Dopamine, which does not cross BBB and therefore
cannot be used directly to treat dopamine deficiency seen in Parkinson’s Disease.
Instead, the prodrug levodopa is given. This is non polar and readily acrosses the BBB.
Once the levedopa reaches the brain, it converted to dopamine

20. FACTORS AFFECTING DISTRIBUTION
•-PROTEIN BINDING
✔A drug comes in contact with proteins such as the plasma protein albumin.
✔The drug can remain free or bind to the protein . Only the free, or unbound , portion
remains active and can insert pharmacological effect.
✔Example Warfarin is a typical example, and shows about 99% binding to plasma albumin.
If any factor changes the degree of plasma protein binding , such as hypoalbuminaemia.
This may lead to toxicity, in the form of an enhanced anticoagulant effect and bleeding.

21. METABOLISM
✔Aka. Biotransformation
✔Biotransformation – is the process by which a drug is enzymatically converted to a
simpler compound.
✔It occurs in the liver , so that persons with liver disease will have difficulty metabolizing
drugs

22. FACTORS AFFECTING METABOLISM
•CONDITIONAL CONSIDERATIONS
✔Certain diseases can reduce metabolism such as liver cirrhosis.
•STRESS TEST
✔Environment, too, can alter drug metabolism. For example cigarette smoke & stressful
situation such as prolong illness, surgery, or injury , can change how person metabolizes
drugs.

23. FACTORS AFFECTING METABOLISM
•THE AGE GAME
✔Infants has a immature livers that reduce the rate of metabolism, and elderly patient’s
experience a decline in liver size, blood flow, and enzyme production that also affect the
liver.

24. EXCRETION
•Excretion, or Elimination – is the process by which a drug is removed from the body
along with its metabolite.
✔The most important excretion routes are through the kidney and liver.
✔Other routes include respiration through the lungs, sweating, or milk in nursing mothers.
✔Most drugs are eliminated in the kidney so elimination is highly influenced by renal
function.
✔If the kidneys are not eliminating properly, the parent drug and metabolism accumulate
and can cause action or toxicity.

25. EXCRETION
✔Carefully assess the renal effect of ALL drugs and check with the physician be
administering two nephrotoxic drugs together.
✔The rate at which a drug is eliminated the body is known as drug clearance . This
process is influenced greatly by renal function, which often measured by creatinine
clearance ( which reflect the glomerular filtration rate)

26. DRUG MONITORING ( HALF – LIFE = HALF
THE DRUG)
✔The amount of time required half of the drug to leave the system is known as drug half
life.
✔It is the time needed for 50% of the drug in the plasma to be eliminated, the blood
concentration of a drug to decreases by 50%.
✔This information is important for appropriate timing for a drug dose or determining the
duration of a drug effects on the body.

27. TOLERANCE
✔When a patient develops a decreased response to a drug over time. The patients then
requires larger doses to produce the same response.

28. DEPENDENCE
✔Patient displays a physical or psychological need for the drug

29. PHARMACODYNAMICS
( HOW THE DRUGS AFFECT THE BODY)
✔Process by which drugs influence the cell physiology to achieve the desire result.
✔PHARMACODYNAMICS – refer to how drugs alter body functions at the cellular level.
It addresses the therapeutic as well as the adverse effects of drugs.
✔Adverse effect : ex. Allergic reactions

30. HOW THE DRUGS PRODUCE THEIR EFFECTS
✔All but small numbers of drugs interact with specific sites called receptors
✔The receptor sites react with certain chemicals to cause an effect within the cell

31. LOCK AND KEY PRINCIPLES
✔To better understand this process, think of how a key works in a lock, The specific
chemical ( the key ) approaches a cell membrane and finds a perfect fit ( the lock ) at a
receptor site.

32. AGONIST ( ACTIVATOR)
✔Bind to the receptor on the cell membrane and act on the cell through the receptor to
produce a pharmacologic effect

33. ANTAGONIST ( BLOCKERS)
✔Bind to the receptor and prevent the cell from producing an effect.
✔May block the action of another drug.

34. CLASSIFICATION
AGONIST
(Activator)
ADRENERGIC RECEPTOR)
Alpha --- Beta



ANTAGONIST
(Blockers)
SALBUTAMOL ( BETA 2 AGONIST) Binds
to and activates beta 2 receptors in the
bronchiolar smooth muscles producing
bronchodilation



Propranolol – a selective beta – blockers blocks
beta 1 receptors in the heart reducing heart
rate



Ranitidine – blocks the( histamine ) receptors
in the gastrointestinal tract, reducing gastric
acd and promoting healing of duodenal ulcer
and gastric ulcers.

35. CLASSIFICATIONS
RECEPTOR SUBTYPES
ADRENERGIC RECEPTORS
ALPHA 1 , ALPHA 2, BETA 1, BETA 2
Examples of drugs used to stimulate block
receptors


Propanolol – blocks beta 1 and beta 2 receptors
in the myocardium ,reducing heart and
contractility. Used in Hypertension and
Angina.



Doxazosin – blocks alpha 1 receptors in blood
vessels, producing vasodilation. Used in
treatment in Hypertension


Salbutamol – stimulates beta 2 receptors on
smooth muscles in bronchi, producing
bronchodilation. Used in asthma

36. Clonidine – stimulates alpha – 2 receptors in
the brain stem, thus reducing the sympathetic
nervous sytem outflow, Used in Hypertension.

37. TERM USED TO DESCRIBE DRUG’S ACTION AT A
RECEPTOR SITE
POTENCY




EFFICACY



SPECITICITY





AFFINITY
-The ability of a drug to produce a response
when it binds to a receptor


- The ability of a drug to produce a response
when it binds to a receptor



-The ability of a drug to combine with one
particular type of receptor. Examples of
receptor; acethylcholine histamine and
adrenoreceptors


-The strength of attraction between a drug
and a receptor

38. THERAPEUTIC INDEX - The relationship between a drug’s desired
therapeutic effects and its adverse effect (
margin effect)

39. INTERACTIONS
✔Drugs may interact with other drugs or food to potentiate (synergize ) or antagonize block
effects)
✔Example: if hydrochlorothiazide decreases blood pressure by 5mm Hg and metropolol also
decreases blood pressure by 5mm Hg, then giving both of these agents to a hypertensive patient
would lower blood pressure by 10 mm Hg
✔Another example: steroids administered to a diabetic client block the effect of insulin
✔- For instance , when food that contains Vitamin K such as green, leafy vegetables) is eaten by a
person taking warfarin, the drugs anticoagulation properties are decreased and blood clots may
form.

40. EXAMPLE OF DRUG INTERACTIONS
KEY DRUG




Benzodiazipines
Ex. Diazepam ( CNS
Deppressant)



BETA – BLOCKERS
B1, B2
ADDITIONAL DRUG




Alcohol





Salbutamol
LIKELY THERAPEUTIC/
ADVERSE OUTCOME



Enhance sedation or severe
CNS Depression resulting
from additive effects as both
drugs have similar actions.


In asthmatic patient, beta
blockers may cause
bronchoconstriction and
precipitate an asthma attack.

41. EXAMPLE OF DRUG INTERACTIONS
KEY DRUG




Potassium Supplement
ADDITIONAL DRUG




ACE INHIBITORS
LIKELY
THERAPEUTIC/ADVERSE
OUTCOME


Combination result
Hyperkalemia Which
precipitate – CARDIAC
ARREST or ARRYTHMIA

42. CONTRAINDICATIONS
✔Factor indicating that the use of a particular drug will cause harm ( allergy)
✔Life – threatening situations. ( Pregnancy and lactations )

43. SIDE EFFECTS VS ADVERSE EFFECTS
SIDE EFFECTS – Expected effect that may or may not cause harm.
✔ Sometimes side effects become intended effects. For example anti- coagulation is a side
effect of aspirin when aspirin is given for inflammation. Yet at certain times, aspirin is
given for its anticoagulant activity.

44. SIDE EFFECTS VS ADVERSE EFFECTS
Adverse Effects – Harmful and unexpected. It maybe seen as an effect in any organ.
-Adverse reactions can assume many forms and are highly dependent on the specific drug.
-No drug does only what is desired of it. All drugs have adverse effects associated with
them.

45. SELECTIVE TOXICITY
✔Ideally, all chemotherapeutic agents would act only on enzyme system that are essential
for the life of a pathogen or neoplastic cell and would not affect healthy cells.
✔The ability of a drug to attack only those systems found in foreign cells is known as
selective toxicity.
✔For example
✔Penicillin – an antibiotic used to treat bacterial infections, has selective toxicity. It affects
an enzyme system unique to bacteria, causing bacterial cell death without disrupting
normal human cell functioning.

46. SELECTIVE TOXICITY
✔Unfortunately, most other chemotherapeutic agents also destroy normal human cells.
Causing many of the adverse effects associated with antipathogen and anti neoplastic
chemotherapy ( ex. Bone marrow cells, Gastrointestinal cell, hair follicles )

47. TOXICITY
✔The drug is acting as a toxin or poison.
✔NEPHROTOXICITY – Is common because drugs ( parent compounds and metabolites )
are expected here.

✔HEPATOXICITY – May occur because drugs are chemicals and can easily damage the
liver as it metabolizes drugs.
✔HEMATOLOGIC EFFECTS – also occur and noted as blood dyscrasia.

48. HYPERSENSITIVITY REACTION
✔This occurs when the client is sensitive to the effects of the drug, has adverse symptoms,
but does not have a allergic reaction.

49. ALLERGIC REACTION
✔An Allergic reaction occurs when the body recognizes the drug as a foreign and
responds by histamine release. The allergic reaction and maybe mild and manifested by a
rash, urticaria, nausea and diarrhea. Or it maybe very severe, causing anaphylaxis.
✔A patient can not be allergic to a drug that has never taken. ( This is why skin testing is
not done among newborns) although can have cross – allergies to drugs within the same
drug class as one formerly taken.

50. PHARMACOTHERAPEUTIC

•INDICATIONS –
1.The desired effect is the intended effect or the reason the drug is administered to a
particular client at a given time.
2.At a times the drug needed has toxic side effects, and the benefits must outweight the
risk.
3.The intended effect of drug must be appropriate for client and the illness.