Week 5 - The Depolarising Shift

Question 1

What are the different phases of the action potential?

Answer 1

Resting
Depolarisation
Repolarisation
Hyperpolarisation

Question 2

What happens in the resting potential?

Answer 2

Membrane potential is -75mV

Intracellular fluid predominantly contains K+
Extracellular fluid predominantly contains Na+

Question 3

What is the resting potential?

Answer 3

-75mV

Question 4

What is the threshold potential?

Answer 4

-55mV

Question 5

What 3 factors stop depolarisation?

Answer 5

1. There is an increase in positive ions inside the neurones (act to repel the positively charged sodium ions from entering the cell)
2. The voltage gated sodium channels start to inactivate
3. There is an increase in potassium conductance

Question 6

What are the 3 stages around PK/PD?

Answer 6

Dosage regimen

  PK (Pharmacokinetics)

Concentration in the plasma

   PD (Pharmacodynamics)

Site of action
EFFECT

Question 7

What does ADME stand for?

Answer 7

Absorption
Distribution
Metabolism
Excretion

Question 8

What is the mechanism of action for sodium valproate?

Answer 8

The exact mechanisms by which valproate exerts it’s effects on epilepsy, migraine headaches and bipolar disorder are unknown

Alters GABA metabolism

Question 9

What are the 2 routes that GABA production?

Answer 9

Glutamate decarboxylase

Succinic semialdehyde

Question 10

What ions are associated with inhibitory synapses?

Answer 10

Cl-

Question 11

What are the most common adverse effects of sodium valproate?

Answer 11

• nausea
• drowsiness
• dizziness
• vomiting
• weakness

Question 12

What are serious adverse effects of sodium valporate?

Answer 12

Bleeding

Add from lecture

Question 13

What is the mode of action of phenytoin?

Answer 13

Preferentially binds to the inactive form of sodium channels

Add from lecture

Question 14

What are the most common side effects are neurotoxic and dose related?

Answer 14

• sedation
• impaired memory
• slurred speech
• nystagmus
• decreased coordination
• confusion
• dizziness
• headache

Question 15

What are examples of non intentional reasons for non compliance?

Answer 15

• forget to use/ refill

Question 16

What percentage of patients are non compliant due to forgetfulness?

Answer 16

23%

Question 17

What percentage of patients are non compliant due to unwanted side effects?

Answer 17

20%

Question 18

What percentage of medications are prescribed to patients in the UK over the age of 65?

Answer 18

45%

Question 19

What percentage of patients aged 75 over take more than 4 drugs?

Answer 19

36%

Question 20

What are the different types of non-adherence?

Answer 20

• Primary (Non-fulfillment)
  Prescription is never filled or initiated
• Secondary (Non-persistence)
  Patient stop taking medication after taking it
  Rarely intentional - usually arise from miscommunication or resource/ capacity limitations
• Tertiary (Non-conforming)
  Medication is not taken as prescribed
  Missed doses, incorrect does, doses taken at the wrong time