L74 Pharmacology

Question 1

What is the definition of a drug?

Answer 1

FDA – a substance intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease. [therapeutic definition]

This is the most used definition

Question 2

Another definition of drug

Answer 2

A substance other than food intended to affect the structure or function of a living organisms.

Question 3

Pharmacology

Answer 3

the science of drugs including their origin, composition, pharmacokinetics, therapeutic use and toxicity.

Question 4

Origin of most drug?

Answer 4

Plants

Question 5

In what drugs will toxicity be found?

Answer 5

ALL of them

Some at low doses, some at higher doses

Question 6

How can we classify the drug?

Answer 6

Agonist bc Antagonist

Question 7

What is an agonist drug?

Answer 7

binds to physiologic receptors and mimics the regulatory effects of an endogenous signaling compound

Question 8

What are the characteristics of agonists drug?

Answer 8

They have

• Efficacy: They have the potential of eliciting the reaction
• Affinity: They have the potential to bind to the receptor

Question 9

Antagonist or Inhibitor

Answer 9

binds to physiologic receptors without any regulatory effects but blocks the binding of the endogenous agonist

Question 10

Antagonist property

Answer 10

Have affinity

No efficacy

Question 11

Atropine

Answer 11

Increases HR by removing the tone of the parasympathetic nervous system on the heart (It constantly decreases HR)

Question 12

Partial Agonist

sometimes called partial antagonist

Answer 12

a drug that produces only a submaximal effect. Drugs activate receptors in a graded manner rather than all-or-none

Question 13

When can a partial agonist act as an antagonist?

Answer 13

When the [endogenous product]&raquo_space; and we give partial agonist then it reduces the response bc it becomes a partial antagonist by being a competition and by eliciting a smaller response

Question 14

Drug selectivity

Answer 14

How many receptors it binds to

less receptors high selectivity

Question 15

Drug specificity

Answer 15

How many responses it has in the body

Usually drug molecules with high selectivity also may exhibit high specificity

Question 16

Atropine

Answer 16

High specificity (Only muscular neural Ach receptor)
Low selectivity (increase HR, Pupil dilation, dry mouth...)

Question 17

Diphenhydramine (Benadryl)

Answer 17

Low specificity (Histamine, muscular receptor,alpha rec)
Low Selective

Question 18

Heparin

Answer 18

Highly specific
Highly selective (only Blood coagulation)

Question 19

What are the domains of Pharmacology?

Answer 19

Pharmacokinetics and Pharmacodynamics

Question 20

Pharmacokinetics

Answer 20

Absorption
Distribution
Biotransformation
Excretion

Physical and Chemical propertied of the drug that inflect of the drug

Question 21

Pharmacodynamics

Answer 21

–> Drug Effects
–> Mechanism of Action
After the drug and its receptor bind, there might be many steps at the cellular level in order to see the reaction that we want, however we see and can measure a reaction

Question 22

What are the kinds of nomenclature that the drug has?

Answer 22

1) Chemical (Not used bc very inconvenience)
2) Generic –> Used anywhere in the world and can be recognized
3) Brand name- Proprietary

Question 23

Explain the reason for using generic names

Answer 23

Bc it can be used anywhere in the world and still be recognized

Question 24

Which name is mainly used?

Answer 24

Generic

Question 25

What kind of receptor can a drug use

Answer 25

1) GPCR
2) Ligand gated channels
3) Voltage Guided channels
4) Intracellular receptors
5) Receptors and enzymes

Question 26

What other mechanism than receptor can a ligand have?

Answer 26

1) an enzyme target (antibiotics, Vt K epoxide reductase)
2) Pumps/ carriers (ex; SSRI in the nervous system)
3) non-receptor mediated ex: antacids

Question 27

What ligands use ligand gates ions channel?

Answer 27

Ach
Serotinin
Glutamate
GABA

Question 28

What is the length of action of drugs w ligand gated ion channels?

Answer 28

ms

Question 29

What are then voltage gated ion channel used by local anaesthesia?
What is the time of action of these drugs?

Answer 29

Na+ voltage gated channels
Ca++ voltage gated channels

ms

Question 30

What is so important about GPCR?

What is their time of action

Answer 30

They serve for amplification

minutes to seconds

Question 31

what is special about ligands and drugs of intracellular receptors?
How do they act? How long?

Answer 31

They are lipophilic and can cross the plasma mb

By protein transcription

Hours
and when drugs are stopped, action is not immediately removed bc we have to wait for the protein made to be degraded

Question 32

What are the typed of receptor-enzyme?

Answer 32

1) Intrinsic enzyme activity ex: Insulin and Tyrosine Kinase
2) Extrinsic receptor

seconds, to minutes

Question 33

Spare receptor

Answer 33

Receptor system that does not require all receptors bound to produce a maximal effect
ex: Insuline where 90% are not needed
beta-adrenergic receptor of human heart muscle, where the majority are active and the minority of the receptors are spare

Question 34

How can a drug be an antagonist?

Answer 34

• Inhibitor that binds to the same receptor as the ligand
• Physiological ex: histamine and epi on bronchioles
• chemical

Question 35

How can we regulate a receptor’s activity?

Answer 35

• Tolerance: decrease response to the same dose over time
• Tachyphylaxis: tolerance over minutes
• Refractoriness: when the receptor-drug dot not couple well w the second messenger they become refractory to further stimulation
• Up/Down regulation of the receptor number

Question 36

How can a drug bind to its target?

Answer 36

1) Covalent. Rarely ex: cancer drugs covalently and permanently bind to DNA
2) Ionic: Very common, can happen at long distance, no need for geometric arrangement (ions or dipoles)
3) H bonds, less common require geometric. rx: drugs that interact w DNA H bond
4) Van der Walls or Hydrophobic bonds–> also DNA

Forces add up