Pharmacology

Question 1

What is a drug?

Answer 1

An external substance that acts on living tissue to produce a measureable change in the function of that tissue

Question 2

Examples of drugs used in dentistry

Answer 2

Local anaesthetics, antimicrobials, anxiolytics [anxiety], analgesics [post-op pain]

Question 3

What are some routes of drugs getting into the body

Answer 3

Oral, intravenous, transdermal, subcutaneous, intramuscular, intravenous etc.

Question 4

Topical defintion

Answer 4

durg is applied to the tissue where it acts

Question 5

systemic drug definition

Answer 5

drug is applied to the whole organism

Question 6

parenteral drug defintion

Answer 6

drug administered by injection

Question 7

transdermal drug definition

Answer 7

drug applied to the skin for absorption

Question 8

subcutaneous drug definition

Answer 8

drug injected into the tissues of the skin

Question 9

intramuscular drug defintition

Answer 9

drug is injected into muscle

Question 10

intravenous drug definition

Answer 10

drug injected into a vein

Question 11

transmucosal drug defintion

Answer 11

drug applied to the mucosa for absorption [oral environmelt]

Question 12

advantages and diasadvantages of transdermal/subcutaneous drugs

Answer 12

adv - no first pass metabolism, allergic reactions localised, prolonged action
disadv - very slow onset, drug cost higher, effect varies from person and site

Question 13

adv and disadv of intramuscular and intravenous

Answer 13

adv - very rapid onset, predicatable plasma levels, no first pass metabolism
disadv - allrgic reactions more severe, short duration of action, access difficulties, no self medication, drug cost higher as purity needed

Question 14

adv and disadv of oral route

Answer 14

adv - socially acceptable, drug formulation can change onset and duration of action
disadv - slow onset, variable absorption, first pass metabolism

Question 15

what is first pass metabolism

Answer 15

refers to drug metabolism, whereby a degree of the concentration of drug is greatly reduced before it reaches the site of action

Question 16

where does first pass metabolism occur

Answer 16

liver

Question 17

MOA of first pass metabolism

Answer 17

all blood from GI tract drains into the hepatic portal vein and then into liver before being passed to systemic venous system. any drugs absorbed from here will pass liver first and undergo FPM.

Question 18

FPM when liver function is reduced

Answer 18

amount of FPM is reduced and greater amount of drug will reach circulation, which could have an accumulative and toxic effect. must consider issues when prescribing.

Question 19

2 types of FPM

Answer 19

inactivation and activation

Question 20

Bioavailability defintion

Answer 20

the proportion of an ingested drug which is available for clinical effect. extent and rate which the drug enters systemic circulation and accessing site of action

Question 21

How can bioavailability be changed

Answer 21

dosage form and route of administration. intravenously - 100% bioavailability. oral - depends on food intake, absorption therefore more variable

Question 22

how are drugs distributed

Answer 22

drugs are dissolved in the blood and transported bound to carriers - usually plasma Albumin

Question 23

Free drug definition

Answer 23

can act upon target sites and may cause an effect

Question 24

Bound drug definition

Answer 24

inactive drug as it is not free to enter the tissue

Question 25

what is drug distribution based on

Answer 25

blood flow and drug ability to dissolve and pass on to different areas. high blood flow areas recieve the most drug

Question 26

one compartment model

Answer 26

drug injected and available in all tissues

Question 27

how do drugs enter the brain

Answer 27

through transcellular passive diffusion through lipid membranes into the brain

Question 28

volume of distribution

Answer 28

different parts of the body are affected differently, some will lipid bind in the tissues, leading to a prolonged effect [like anaesthetic gas]

Question 29

which organs is drug excretion done through

Answer 29

liver and renal[kidney]

Question 30

Phase 1 metabolic reaction

Answer 30

reactions will allow drug to change itself
e.g. oxidation, reduction, hydrolysis

Question 31

Phase 2 metabolic reaction

Answer 31

conjugation of the drug and then secretion
e.g. acetylation, sulphation

Question 32

Routes of excretion of drugs

Answer 32

Renal through urine. Liver by bile. Lungs by inhaled gas. Small proportions through sweat, tears and saliva.

Question 33

Renal excretion depends on…

Answer 33

blood flow. disease may impact on ability to excrete blood, keep in mind when prescribing drugs, NSAIDs worsen problem.

Question 34

What to consider when prescribing drugs?

Answer 34

age of the px [very old or young]
medical hisory, are there any conditions which will worsen or impair drug action
interactions between medications they may already be on

Question 35

local anaesthetic MOA

Answer 35

block sodium channels, bind and block transmission of pain information.
e.g. lidocaine, articaine

Question 36

analgesics

Answer 36

given to reduce pain
e.g. ibuprophen, paracetomol, codeine

Question 37

antibiotics

Answer 37

given to kill infection
e.g. metronidazole, amoxacillin

Question 38

sedative drugs

Answer 38

nitric oxide (NOS)
midazolam (GABBA) intravenously
still need to monitor airway, pulse, BP etc

Question 39

emergency drugs

Answer 39

adrenaline for anaphylaxis
inhalers for asthma attacks
heart attacks