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2. Definition of Pharmacology
Pharmacology is the study of the interactions that
occur between our body and chemicals. Knowing
more about the action and uses of a drug.

3. Importance of Pharmacology
to OHT
• Knowledge of how and when
the drug is administered
• Improve patient experience
• Increase the efficiency of
dental procedures
• Provide clear explanation of
drug to patient (only when
prescribed)
• Improve infection control and
prevent fatality

4. HOW PHARMACOLOGY IS
INCORPORATED IN
DAILY PRACTICES?

5. WHAT TYPE OF SCENARIOS
CAN WE FACE?
Medications/ Ulcer Creams/ Local Anesthesia

6. Medication/ Ulcer Creams/ Local Anesthesia
MEDICATIONS

7. MEDICATIONS
Medication/ Ulcer Creams/ Local Anesthesia
In what situations is medication incorporated to
the job of a OHT?
Almost everyday!
When taking medical history
we need to be aware of
diseases that the patient
might have. Especially if poses
any risks during dental
procedures.

8. MEDICATIONS
Medication/ Ulcer Creams/ Local Anesthesia
In what situations is medication incorporated to
the job of a OHT?
When treating patients who are
at high risk of infective
endocarditis, sudden bacteremia
may be produced by dental
manipulation within the mouth.

9. MEDICATIONS
Medication/ Ulcer Creams/ Local Anesthesia
Who are at high risk of infective endocarditis?
Congenital Heart
Disease
Rheumatic
Heart Disease
Congenital
Heart Disease

10. MEDICATIONS
Medication/ Ulcer Creams/ Local Anesthesia
So, when treating such patients…
 To get approval from doctor
 Example of common medication
given is antibiotics-amoxillin.
 Better absorbed, following oral
administration
 Amoxicillin is one of the most
common antibiotics prescribed
for children

11. MEDICATIONS
Medication/ Ulcer Creams/ Local Anesthesia
In a dental clinic

12. ULCER CREAMS
Medication/ Ulcer Creams/ Local Anesthesia
When a patient walks in to a clinic…
1.We need to identify the
cause of the ulcer
2. Consider treating it
3. Prescribe ulcer cream

13. ULCER CREAMS
Medication/ Medication/ Ulcer Ulcer Creams/ Creams/ Local Local Anesthesia
Anesthesia
And now, an advertisement

14. LOCAL ANESTHESIA
Medication/ Ulcer Creams/ Local Anesthesia
When local anesthesia is used?
Cavity Preparation Extraction of teeth Removal of Gum Polyp

15. LOCAL ANESTHESIA
Medication/ Ulcer Creams/ Local Anesthesia
Medication/ Ulcer Creams/ Local Anesthesia
A live extraction in class

16. ACTIVITY
Purpose/ Route of Entry/ Packaging/ Form of Medicine

17. USES OF DRUGS

18. Uses of Drugs
ANTIBIOTICS
• Also known as antibacterials
• Organic substances either produced by micro-organisms or
synthetically manufactured
• Drugs used to treat infections caused by bacteria
• Inhibit growth of bacteria and other micro-organisms
• Not effective against viruses

19. Uses of Drugs
ANTISEPTICS & DISINFECTANT /
HAEMOSTATICS & STYPTICS
Antiseptics & Disinfectants
• Basic tools of cleaning
and sanitizing
• Eliminate disease-causing
organisms
Haemostatics & Styptics
• Blood clotting agents
• Arrest the flow of blood
(clotting)
• Promote vasoconstriction

20. Uses of Drugs
Pain & Pain Control / Vasoconstriction
Pain & Pain Control
• Manage and subdue
pain faced by patience
• Provide ease to operator
to carry out procedure
Vasoconstriction drugs
• Blanching of tissues
• Narrows blood vessels

21. Internal/ External
ROUTE OF ADMINISTRATION

22. Route of Entry
External Route
On the skin
Mucous
membrane of
mouth
Mucous
membrane of
rectum
Internal Route
Ingestion, Oral
Route Injection
Inhalation

23. Internal/ External
EXTERNAL ROUTE

24. External Route
• Applied on the surface: local
effects only.
• Depending on chemical
structure and quantity applied
• Can be absorbed by the skin
and mucous membrane
• Greatest Penetration: drugs
with low molecular weight
with a high water and lipid
solubility

25. External Route
Point of Entry Examples
On the skin Creams, Lotions
On the mucous membrane
of mouth
Lozenges, Gargles
On the mucous membrane
of rectum
Suppositories

26. Internal/ External
INTERNAL ROUTE

27. Internal Route
1) Ingestion or Oral Route
a. In the mouth, some drugs are readily and rapidly
absorbed via the mucous membrane in the mouth
b. In the stomach and small intestine, drugs that are
swallowed are absorbed through the lining mucosa

28. Internal Route
2) Injection
a) Intradermal – in the layers of the skin
b) Subcutaneous – into the undersurface of the skin
c) Intramuscular – into the deep-seated muscles
d) Intravenous – into the veins
e) Intraspinal – into the spinal space

29. Internal Route
3) Inhalation
• Drugs in the form of vapor
may be inhaled into the lungs.
• Very small molecular
structure and pass easily
through the thin epithelium.
• Absorbed through pulmonary
endothelium at alveoli to gain
rapid access to the general
circulation

30. PACKAGING

31. • To carry the product and keep it stable, till it is
consumed
• Transparent
capsules & syrup in
a transparent glass
bottle is preferred a
lot more

32. • They are not only attractive but are also more
trustworthy because patients can “see” what they are
consuming
• Most manufacturers are no longer hiding the
medicines behind opaque covers

33. FORM OF MEDICINE

34. • Many tablets today are coated after being pressed.
Some coatings are just to provide colour or a smooth
finish, or to facilitate printing on the tablet

35. • Some tablets have coatings which is designed to hold
the tablet together when it is in the stomach
• The coating is designed to hold together in acid
conditions and break down in non-acid conditions and
therefore release the drug in the intestines
• Example: Aspirin
• An enteric coating is
there usually for a good
reason and therefore
such tablets or the
contents of enteric
coated capsules should
never be crushed before
being taken.

37. • Hard-shelled capsules, which are normally used for
dry, powdered ingredients or miniature pellets

38. • Soft-shelled capsules, primarily used for oils and for
active ingredients that are dissolved or suspended
in oil

39. • Solutions, syrups and mixtures
• Commonly used in patients that have difficulty
swallowing medicines like children and the elderly
• The liquid medicine should be made such that the
dose needed will be a sensible volume such as 5ml
(one teaspoon)

40. ACTIVITY
Purpose/ Route of Entry/ Packaging/ Form of Medicine
ENTRY PACKAGING FORM OF
PURPOSE ROUTE OF
MEDICINE
1. Antiseptics
2. Pain control
3. Haemostatics
and Styptics
4. Antibiotics
5. Vasoconstriction
External route
1. Skin
2. Oral Mucosa
3. Membrane of
rectum
Internal Route
1. Ingestion
2. Injection
3. Inhalation
1. Hard shelled
Capsules
2. Soft Shell
Capsules
3. Liquid
4. Coated Tablets
1. Blister
Pack
2. Bottle
3. Tube

41. ABSORPTION OF DRUG

46. ALVEOLI
Absorption

47. Absorption of Drug
• Absorption is the process by which a drug
passes from its site of administration into the
circulation (bloodstream).
• The blood receives a drug from the site of
administration and carries it to all the organs,
including those on which the drug acts.
• The speed, ease, and degree of absorption
are related to the route of administration.

48. Absorption of Drug
• The absorption rates of drugs depend on its
physical and chemical properties, on the site
of absorption and the solubility of drug.
Site of Absorption Rate of Absorption
In mucous membrane Rapid
In small intestine Depends on health of stomach
and its activity and
presence/absence of food
Subcutaneous and
Intramuscular injections
Depends on water solubility of
drug, dose form and blood
supply at site.
Intravenous Injection Immediate
Inhalation Immediate

49. DISTRIBUTION OF DRUG

51. Distribution of Drug
• After the drug is absorbed, it is then distributed to
various organs of the body.
• Influenced by how well each organ is perfused, organ
size, binding of the drug to various components of
blood and tissues, and permeability of tissue
membranes.
• The more fat-soluble a drug is, the higher its ability to
pass across the cell membrane is.
• Protein binding is an important consideration
influencing drug distribution.
• Many drugs are bound to blood proteins such as
serum albumin and are not available as active drugs.

52. METABOLISM OF DRUG

53. METABOLISM

54. METABOLISM

55. Metabolism of Drug
• Metabolism occurs via two types of reactions:
and
• Goal: Change the active part of medications (a.k.a
functional group) making them more water-soluble and
more readily excreted by the kidney.
• Changing the molecular structure of drugs= water
solubility= fat solubility= faster excretion of drug in the
urine.

56. Metabolism of Drug: Phase I
• Phase I: reactions involve oxidation, hydrolysis,
and reduction.
• Oxidation and reduction processes make a
molecule's charge more positive or negative than
the original drug.
• Regardless of the positivity or negativity, a
charged molecule = dissolvable in water
• Take place primarily in the liver by enzymes
• Oxidative metabolism may result in formation of
an active metabolite or inactive compound.

57. Metabolism of Drug: Phase II
• Phase II: reactions involve conjugation to form
glucuronides, acetates, or sulfates, by adding
glucose, acetate, or sulfate molecules, respectively.
• These reactions generally inactivate the
pharmacologic activity of the drug and may make it
more prone to elimination by the kidney.

58. EXCRETION OF DRUG

59. EXCRETION

60. Excretion of Drug
• Excretion of a drug = duration of action=
toxicity.
• Drugs may be eliminated as a parent drug
(unchanged) or as metabolites (changed form).
• PharmacoDYNAMICS: what the drug does to the
body; this term refers to the action of the drug at
the tissue-,cellular-, and molecular level.
– Specific and different for each drug

61. PharmacoKINETICS: what the human body does to the drug
Excretion occurs primarily through the urine.
Fecal excretion is seen with drugs that are not absorbed
from the intestines or have been secreted in the bile.
sweat

62. KIDNEY
• Most important organ for elimination of drugs
and its metabolites
• Eliminated in the urine
① Passive glomerular filtration (most drugs)
② Active tubular secretion (e.g. penicillin)
③ Passive tubular secretion (e.g. salicylates)
• In the case of renal damage:
 excretion of drugs;  toxicity

63. BILE
• Usually involve orally ingested unabsorbed
drugs or metabolites excreted in the bile, that
are not reabsorbed from the small intestine
• Eliminated through feces
• Examples of drugs
– Phenytoin
– Phenolphthalein

64. INTESTINES
• Oral and enteral medications (like purgatives) are
absorbed in small intestine
• Excreted in large intestine
• Eliminated through stools
• Example:
– senna
– cascara

65. LUNGS
• Drugs like volatile general anaesthetics, ethyl alcohol are
excreted through lungs
• Most drugs excreted here are not metabolized first
• Example:
– Ketamine
– propofol

66. SALIVA
• Drugs like iodides and
metallic salts are excreted
through saliva.
• Such as lead is eliminated
through saliva and its
deposition produces black
lining of teeth.

67. SWEAT
• Heavy metals like arsenic
and mercury are excreted
through skin.

68. BREAST MILK
• Breast milk is more acidic than
plasma
• May produce drug toxicity in the
nursing infant
• Pulmonary excretion (e.g.
breathing) is important as it
pertains to the elimination of
anesthetic gases and vapors, as
well as alcohol.
• Example: pethidine

69. Video

70. FACTORS TO CONSIDER WHEN
PRESCRIBING DRUGS

71. FACTORS TO CONSIDER WHEN PRESCRIBING DRUGS
Dosage of
drugs
Presence of
other drugs
Time of
administration
Patient
compliance
Weight of
patient
Age
Sex
Severity of
the disease

72. Dosage of drugs
• Weight of patient
Dose = Adult Dose x Weight (kg)
• Age
Age x Adult dose
70
Age + 12
• Sex
Females are given 7/8 male dose.
• Neonates-new born(calibrated
dose)
• Infants-1-6 years(1/4 adults dose)
• Children- 6-12 years(1/2 adult
dose)

73. Presence of other drugs
• Some drugs cancel each other’s effects
• Combined effect would be harmful to the
patient
• Hence, consideration must be taken if patient
is on other drugs

74. Time of administration
• Time relationship to meals could influence the
actual effective therapeutic dose
• Absorption occurs more rapidly if stomach
and upper portion of body are free from food
• Drug action may depreciate when medication
given after a meal
• Irritant forms of medication are better
tolerated if food already present in gut.

75. Patient compliance
• Patient does not take medication due to:
o Lack of faith in medication
o Poor understanding of illness
• Patient takes medication incorrectly
• Patient stops taking medication midway

76. FACTORS THAT MODIFY
DRUG EFFECTS

77. FACTORS THAT MODIFY DRUG EFFECTS
Patient compliance
Other drugs
Age & Weight
Rate of elimination
Physiological factors
Tolerence and cross-tolerence
Sex
Pathologic factors
Route of administration
Time of administration
Psychological factors
Genetic variation

78. 10
8
6
4
2
0
Blood Concentration VS Time Curve
of Repeated Dosing
8 16 24 32
1st Dose
2nd Dose
3rd Dose
No Effect
Toxic Level
Blood Concentration
Time
Distribution
+
Metabolism
HALF –LIFE/
THERAPEUTIC
LEVEL

79. CONCLUSION!
1. Pharmacology and it’s
use
2. Route of administration
3. Packaging
4. Form of drugs
5. Absorption, Distribution,
Metabolism, Excretion of
Drugs

80. THANK YOU FOR LISTENING
NYP DENTAL HYGIENE AND THERAPY 2012