CNS active drugs

Question 1

common CNS drug targets are

Answer 1

• receptors
• channels
• transporters
• enzymes
• membranes

Question 2

long term effect of CNS drugs

Answer 2

• neuronal plasticity
• neurotrophic effects
• cytoarchitectual changes

Question 3

rate of effect

Answer 3

drugs that effect ion channels create quick effects

drugs that target kinase linked receptors and gene expression take longer

Question 4

what are the theories of depression

Answer 4

1. monoamine disruption
   - NE and serotonin
2. Neuroendocrine (HPA axis)
3. Neurotrophin

Question 5

Antidepressant drugs

Answer 5

1. inhibitors of monoamine uptake
   - SSRI
   - 5HT reuptake inhibitors
   - NE reuptake inhibitors
   - 5-HT/NE reuptake inhibitors
2. tricyclic antidepressant (older)
3. monoamine receptor antagonists
4. monoamine receptor inhibitors

Question 6

Bipolar drugs

Answer 6

• lithium
• anti-convulsants
• atypical antipsychotics

Question 7

Lithium is…

Answer 7

a mood stabiliser

it is taken up by voltage dependant Na+ channels (and causes depolarisation by K+ loss

it has a narrow therapeutic window

Question 8

Anti-psychotics….

Answer 8

antagonise D2 receptors

1. typical antipsychotics (antagonise D2)
   - chlorpromazine, haliperidol

causes tardive dyskinesia, and parkinsonism

2. atypical antipsychotics (5HT antagonism > D2)
   - clozapine, olanzepine

Question 9

Sedatives or anxiolytics

Answer 9

1. Benzodiazepines (GABAa agonists)

tolerance, withdrawal and respiratory depression common

2. Alcohol

increases GABAa, K channels
reduces NMDA and Ca channels

CNS depression

Question 10

Caffeine

Answer 10

adenosine antagonist

increases concentration, creates global vasoconstriction, and is BBB penetrable

Question 11

Psychomimetics

Answer 11

are serotonin agonists

all are hallucinogenic - adjust content of consciousness and perception

1. LSD - can precipitate schizophrenia
2. MDMA - ecstacy (amphetamine derivative) - can lead to hyponatraemia and hypothermia from excessive water consumption
3. Ketamine - NMDA blocker, used in children (dissociative anaesthetic)

Question 12

Analgesics

Answer 12

1. opiods - works on mew receptor

2. cannabis (delta4THC) - works on endogenous cannabinoid receptors - antipsychotic, anxiolytic

Question 13

Nicotine

Answer 13

increases alertness and memory

• nicotinic acethylcholine receptor

Question 14

Psychostimulants

Answer 14

Activate dopamine transporters
1. Cocaine (inhibitrs dopamine reuptake)
>50% have bugs crawling under skin
2. Amphetamines
schizophrenic psychosis

Highly addictive

Ritalin is used (dextroamphetamine) in ADHD children

Question 15

Anti-epileptics

Answer 15

1. inhibit voltage gated sodium channels
   carbamazepine and phenytoin
2. Calcium current drugs - absence seizures
3. GABA agonists - phenobarbitol and benzodiazepine
4. Glutamate receptor antagonists