Pharmacodynamics Flashcards

1
Q

What is the definition of pharmacodynamics?

A

What the drug (chemical) does to the body and how the body responds

Interaction between chemical compounds of the body and foreign chemicals

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2
Q

What are the 4 ways in which drugs tend to work?

A

1) replace missing chemicals/act as their substitutes
2) stimulate particular cell activities
3) slow down/inhibit particular cell activities
4) interfere with function of foreign cells

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3
Q

What are the 4 types of proteins drugs mainly exert their effects on?

A

1) receptors
2) enzymes
3) ion channels
4) carrier (transporter) molecules

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4
Q

Define receptor…

A

Protein molecule

Has a specific shape/3D structure

Only substances that fit precisely can interact (complementary)

Enable natural substances e.g. NT/hormones to influence activity of the cell- influence may be stimulate or inhibit process inside cell

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5
Q

What is a ligand?

A

Molecule/chemical that binds to a receptor

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6
Q

What are target cells?

A

Cells with the appropriate receptor to detect/respond to hormones, mediators and NT

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7
Q

Define specificity…

A

Ability of the drug to combine with one particle type of receptor

No drug acts with complete specificity- this causes unwanted side effects

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8
Q

Define efficacy…

A

Measure of the bound ligand to activate a response

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9
Q

Define affinity…

A

Interaction between drug and binding site

Closer the fit and greater number of bonds leads to higher affinity of the drug for the receptor

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10
Q

What is the effect of an Agonist drug?

A

Activate or stimulate their receptors

Trigger a response to increase or decrease cell activity

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11
Q

What is the effect of an Antagonist drug?

A

Block the access/attachment of body’s natural agonists (NT) to receptors

Prevent/reduce cell responses to natural agonists

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12
Q

Define agonist…

A

Mimic action of endogenous (naturally occurring) ligands

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13
Q

Define antagonist…

A

Block action of endogenous ligands

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14
Q

What is the function of a reversible competitive antagonist?

A

Competes with the agonist for the agonist binding site on the receptor- blocks it, stopping agonist binding

Increasing agonist conc. can overcome blocking effect , restoring response

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15
Q

What is the function of irreversible, competitive antagonists?

A

Forms covalent bonds to agonist binding site so block cannot be overcome

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16
Q

What are the functions of non-competitive antagonists?

A

Bind to a site other than agonist binding site

Often causes conformational change in receptor, reducing ability of the agonist to bind to its binding site- reduces response to agonist

17
Q

What are the functions of alpha-receptors?

A

Associated mainly with increased contractibility of vascular smooth muscle and intestinal relaxation

18
Q

What are the functions of beta-receptors?

A

Associated with vasodilation and relaxation of non-intestinal smooth muscle and cardiac stimulation

19
Q

What is an enzyme?

A

A protein which acts as a biological catalyst

Controls rate at which reactions occur

Remain unchanged

20
Q

What is the function of the active site?

A

Where chemical reactions occur

Where the enzyme interacts with its substrate

The prime target for drugs acting on enzymes

21
Q

What is the function of non steroidal anti-inflammatory drugs (NSAIDS)?

A

Drugs that block activity of an enzyme

Inhibit enzyme cyclo-oxygenase (COX)- block its activity

22
Q

What is the function of COX?

A

Responsible for formation of some important chemical mediators e.g. Prostaglandins- play key role in inflammation and pain

23
Q

What is the function of acetylcholinesterase inhibitors?

A

Used to improve/stabilise symptoms of Alzheimer’s disease

Breaks acetylcholine in the synapse- if you inhibit breakdown of acetylcholine more NT would remain in synapse, enhancing memory

24
Q

What is the function of Acetylcholine?

A

NT helping with memory and thinking

25
What are the functions of calcium channel blockers?
Act as vasodilators- blocking intracellular calcium required for contraction of arteriolar smooth muscle Reduce aldosterone production (adrenal cortex) Lowers BP Slows HR Reduce force of contraction in cardiac smooth muscle Negative chronotrophic effect- atrial fibrillation possibly causing heart block
26
What does vasodilation cause in calcium channel blockers?
Causes reduction in peripheral vascular resistance- reduced BP
27
What are the functions of sodium channels?
Vital for propagation of AP along nerve cells
28
What happens if sodium channels are blocked?
Prevents sensation of pain Delay in conductance, decrease in excitability and prevents sensations of pain
29
What are the functions of potassium channel blockers?
Prolongs repolarisation (going back to resting state)
30
What are the functions of potassium channel openers?
Used to rest hypertension and angina- relax smooth muscle- vasodilation
31
What is the function of GABA?
Most common NT Acts to reduce excitability in CNS Reduced signalling in the brain Sedating NT
32
What are the functions of Benzodiazepines?
Act as modulators of GABA receptors, potentiating effect of the receptor
33
What is the function of Serotonin?
In the CNS it is a mood enhancer Increasing levels in synaptic cleft available to bind to postsynaptic receptors causing mood enhancement
34
What is the function of Selective Serotonin Reuptake inhibitors?
Prevent reuptake of Serotonin from synaptic cleft back into the pre-synaptic neurone