Introduction to Dental Pharmacology

Question 1

What is pharmacology?

Answer 1

The study of the sources, uses, effect, and mechanisms of action of drugs.

Question 2

What is pharmacodynamics?

Answer 2

What drugs do to the body.

Question 3

What is pharmacokinetics?

Answer 3

What the body does to the drugs.

Question 4

What is a drug?

Answer 4

A drug is a chemical which is utilized for the diagnosis, prevention, cure or amelioration of an unwanted health condition in humans.

All drugs are chemicals; BUT not all chemicals are drugs.

All drugs are poisons; BUT not all poisons are drugs.

Question 5

What is toxicology?

Answer 5

Toxicology is a branch of pharmacology that deals with undesirable/unwanted effects of chemicals on living systems.

Question 6

Define therapeutic index.

Answer 6

Therapeutic Index (TI) = TD50/ED50

• ED50: Dose produces specified “therapeutic effect” in 50% of animals
• TD50: Dose produces toxic/adverse effect in 50% of animals

Question 7

How does therapeutic index relate to drug margin of safety?

Answer 7

The higher the TI, the safer the drug, the wider the Margin of Safety

• Higher TI drugs: e.g. Ranitidine, omeprazole, diazepam - higher safety
• Lower TI drugs: e.g. theophylline, warfarin - lower safety

Question 8

List at least 5 factors that can influence the severity of drug adverse effects

Answer 8

Severity of adverse drug effects can be different by gender, genetic make-up, age, pregnancy, underlying pathology, immunity, drug-drug interaction.

Question 9

Name at least TWO factors on each side of the therapeutic balance of risk-benefit ratio for patients.

Answer 9

Question 10

List FIVE steps in rationale prescribing.

Answer 10

1. Making a diagnosis
2. Consideration of treatment options
3. Prescription
4. Patient counselling
5. Monitoring

Question 11

List at least THREE patient factors and THREE drug factors that should be considered when making a prescription.

Answer 11

Patient factors

1. Age and gender
2. Interacting diseases
3. Interacting drugs
4. Genetics

Drug factors

1. Pharmacokinetics
2. Pharmacodynamics
3. Evidence-base
4. Cost-effectiveness

Question 12

Why do dentists need to know pharmacology?

Answer 12

Because knowledge of pharmacology saves lives.

Question 13

What are the three regulatory categories regulating sale of medicines?

Answer 13

1. Over-the-Counter Medicines (General Sales)
   * Examples: antacids, paracetamol, aspirin
2. Pharmacy-Only-Medicines
   * Examples: antihistamines, cough, antidiarrhoeals
3. Prescription-Only-Medicines (by registered Medical Practitioners)
   * Examples: antibiotics, antihypertensive, anti-diabetics…