Psychiatric Disease and Parkinsons

Question 1

Levodopa- administration

Answer 1

Dopamine can’t cross BBB but L-dopa can :)

Given with dopa decarboxylase inhibitor to stop inactivation of L-dopa in periphery e.g. Co-careldopa

Question 2

Levodopa- half life

Answer 2

SHORT (2hrs) so regular dosing needed, fluctuating symptoms

Question 3

Levodopa- ADRs

Answer 3

Psychosis, nausea, motor complications (freezing, involuntary movements, on/off fluctuations), decreased efficacy over time due to decreased dopaminergic neurones

Question 4

Dopamine receptor agonists- ADRs

Answer 4

Hallucinations, nausea, sedation, impulse control disorder (gambling, sex shopping etc addiction!! Increased risk with ergot than non-ergot dopamine agonists), ergot- valvular heart disease

Question 5

MAO inhibitors- mechanism

Answer 5

MAO breaks down dopamine, inhibiting it increases dopamine! Prolongs levodopa action and smooths out motor symptoms

Question 6

COMT inhibitors- mechanism

Answer 6

Inhibits levodopa breakdown in periphery (doesn’t cross BBB) increases amount of levodopa in CNS, decreases ‘wearing off’ of levodopa

Question 7

SSRIs- mechanism

Answer 7

Inhibit serotonin re-uptake by neurones = more stays in synapse -> increase serotonin

Question 8

SSRIs- use?

Answer 8

1st line moderate to severe depression

Question 9

SSRIs - ADRs

Answer 9

Anorexia, nausea, mania, increase suicidal ideation,

Question 10

SNRIs- mechanism

Answer 10

SSRIs plus NA re-uptake inhibition

Question 11

SNRIs- use?

Answer 11

2nd/3rd line for moderate- severe depression

Question 12

SNRIs- ADRs

Answer 12

As SSRIs plus withdrawal, increased BP and dry mouth

Question 13

Tricyclic antidepressants- mechanism

Answer 13

Many- serotonin and NA re-uptake inhibition, anticholinergic, block a1 adrenoceptors

Question 14

TCAs- use?

Answer 14

Not 1st line, occasional use e.g. Amitryptiline

Question 15

TCAs- ADRs

Answer 15

Sedation, seizures, tachycardia, impaired myocardial contractility, long QT

Question 16

What can be used to treat anxiety?

Answer 16

SSRIs, GABA agonists (benzodiazepines)

Question 17

What drugs can be used to treat bipolar disorder?

Answer 17

Lithium, AEDs (carbamazepine, valproate, lamotrigine), atypical anti-psychotics

Question 18

Lithium- mechanism?

Answer 18

Many theories- increase serotonin, compete with Ca, Mg, attenuate effects of neurotransmitters -> treat both mania and depression and reduce suicidality :)

Question 19

Lithium- ADRs

Answer 19

Memory problems, thirst/polyuria, tremor, kidney failure, hypothyroidism, TOXICITY!

Question 20

Lithium- monitoring?

Answer 20

3 monthly plasma drug levels, renal and thyroid function before starting and every 6 months

Question 21

Levodopa- mechanism?

Answer 21

Taken up by dopamine rigid neurones in substantia nigra and converted to dopamine :D

Question 22

What pathways involved in schizophrenia?

Answer 22

Too much dopamine (most drugs antagonise dopamine), serotonin (clozapine is serotonin antagonist)

Question 23

Clozapine- monitoring

Answer 23

Monitor FBCs for neutropenia

Question 24

1st line treatment for psychosis?

Answer 24

Atypical antipsychotic e.g. Olanzapine

Question 25

Antipsychotics- ADRs

Answer 25

Typical- extra pyramidal signs
Atypical- weight gain, prolactinaemia
All- neuroleptic malignant syndrome (medical emergency), sedation, CNS depression

Question 26

Antipsychotic administration

Answer 26

Oral (daily) or depot injection every few weeks

Question 27

ACh esterase inhibitors- mechanism?

Answer 27

ACh involved in arousal, mood, memory, increase ACh slows progression of Alzheimer’s

Question 28

ACh esterase inhibitors ADRs?

Answer 28

GI disturbance, fatigue, bradycardia, headache

Question 29

Memantidine- mechanism and ADRs?

Answer 29

NMDA antagonist, ADRs hypotension, headache, dizziness, drowsiness