Neurology/Psychiatry Drugs Flashcards
List the 3 main types of Parkinson’s drugs.
Give an example of each.
Dopamine precursors (e.g. levodopa)
Dopamine agonists (e.g. apomorphine)
Catechol-o-methyl transferase (COMT) inhibitors (e.g. entacapone)
List the 5 main anti-epileptics.
Carbamazepine Sodium valproate Phenytoin Lamotrigine Levetiracetam
Briefly describe the mechanism of action of levodopa. (2)
List 5 common side effects.
MECHANISM:
- Cross the BBB and is converted to dopamine in the pre-synaptic bulb (via decarboxylation)
- This increases neurotransmission in the striatum
SIDE EFFECTS: Dyskinesia Compulsive disorders Hallucinations Nausea GI upset
Briefly describe important pharmacokinetics/dynamics of levodopa. (4)
What would you tell the patient when prescribing? (3)
IMPORTANT PHARMA INFO:
- Converted into dopamine in the peripheries, causing GI/motor side effects
- Prescribed with a dopamine decarboxylase inhibitor or COMT inhibitor
- Half-life: 50-90 minutes
- Rapid GI absorption via large neutral amino acid (LNAA) carriers
PATIENT INFO:
- Dyskinesia is very common
- Reduced efficacy over time
- Avoid abrupt withdrawal
List 5 examples of dopamine agonists.
Which one is non-selective?
Which one is selective? (And which is the only dopamine receptor it works on?)
Apomorphine (non-selective)
Pramipexole (selective - D3)
Bromocriptine
Pergolide
Rotigotine
Briefly describe the mechanism of action of dopamine agonists. (2)
- Directly stimulate post-synaptic dopamine receptors
- Type of dopamine receptor depends on the specific drug, e.g.
- Apomorphine: non-selective: D1 and D2 receptors
- Pramipexole: selective: D3 receptor only
For apomorphine, list:
a) What type of drug is it?
b) Common side effects (3)
c) Important pharmacokinetics/dynamics (4)
d) What would you tell the patient? (2)
Non-selective D1 and D2 dopamine agonist
SIDE EFFECTS:
Pain at injection site
Nausea
Vomiting
IMPORTANT PHARMA INFO:
- Highly emetic
- Half-life: 40 minutes
- Administration: injection
- Reduced efficacy over time
PATIENT INFO:
- Can only be injected
- Less effective than L-dopa; treatment may need to be modified later
For pramipexole, list:
a) What kind of drug is it?
b) Common side effects (4)
c) Important pharmacokinetics/dynamics (3)
d) What would you tell the patient? (1)
Selective D3 dopamine agonist
SIDE EFFECTS: Hallucinations Nausea Drowsiness Involuntary movements
IMPORTANT PHARMA INFO:
- Cimetidine increases toxicity
- Half-life: 8 hours
- Reduced efficacy over time
PATIENT INFO:
-Weaker than L-dopa; treatment may need to be modified
Give 1 example of a COMT inhibitor.
Briefly describe its mechanism of action. (2)
In Parkinson’s disease, what would you prescribe in conjunction with this? (2)
Entacapone
MECHANISM OF ACTION:
1. Inhibits catechol-o-methyl transferase, which breaks down levodopa in the peripheries
- COMT converts L-dopa into 3-OMD, which does not cross the BBB, making l-dopa less effective
a. COMT inhibitors prevent this, making L-dopa more effective
PRESCRIBED WITH:
Levodopa
Dopamine decarboxylase inhibitor
List 6 common side effects of COMT inhibitors.
Briefly describe the important pharmacokinetics/dynamics. (2)
What would you tell the patient when prescribing COMT inhibitors? (3)
SIDE EFFECTS: Dyskinesia Nausea Abdominal pain Vomiting Dry mouth Dizziness
IMPORTANT PHARMA INFO:
- Rapid absorption
- Levodopa dose needs to be reduced (by 10-30%)
PATIENT INFO:
- Urine may turn brown (normal)
- Lightheaded/dizziness may occur during normal daily activities
- Avoid abrupt withdrawal
List 5 examples of SSRIs.
Citalopram Fluoxetine Paroxetine Escitalopram Sertraline
Describe the mechanism of action of SSRIs. (2)
What are the indications for prescribing SSRIs? (3)
MECHANISM OF ACTION:
1. Inhibition of serotonin reuptake at the serotonin reuptake pump of the synaptic cleft (in CNS)
- Increases serotonin stimulation of 5-HT1A and terminal autoreceptors
INDICATIONS:
Depression
Bulimia
OCD
List 5 common side effects of SSRIs.
List 2 serious, but rare side effects of SSRIs.
COMMON SIDE EFFECTS: Dry mouth Nausea Insomnia Anxiety Decreased libido
RARE SIDE EFFECTS:
Seizures
Dyskinesia
Describe important pharmacokinetics/dynamics of SSRIs. (2)
What would you tell the patient when prescribing SSRIs? (3)
IMPORTANT PHARMA INFO:
- Less binding to histamine/ACh/NA receptors than TCAs, therefore fewer side effects
- Less dangerous in overdose than TCAs
PATIENT INFO:
- Toxicity possible with alcohol
- Symptom improvement may take several weeks
- Abrupt discontinuation may cause withdrawal
List 3 examples of tricyclic antidepressants.
Amitryptyline
Imipramine
Doxepin
Describe the mechanism of action of TCAs. (2)
What are the indications for prescribing TCAs? (3)
MECHANISM OF ACTION:
1. Inhibit reuptake of monoamines by binding to the monoamine pump at the pre-synaptic cleft
- This causes reduced reuptake of noradrenaline and/or serotonin, improving depression
INDICATIONS:
Depression
Panic disorders
Neuropathic pain
List 7 side effects of TCAs.
HINT: there are 3 categories of side effects.
ANTI-HISTAMINERGIC SIDE EFFECTS:
Sedation
ANTI-ADRENERGIC SIDE EFFECTS:
Postural hypotension
Tachycardia
ANTI-CHOLINERGIC SIDE EFFECTS: Urinary retention Dry mouth Blurred vision Diplopia
Describe the important pharmacokinetics/dynamics of TCAs. (3)
What would you tell the patient when prescribing TCAs? (2)
IMPORTANT PHARMA INFO:
- Action on other receptors causes many side effects
- Good oral absorption
- First pass metabolism via liver
PATIENT INFO:
- Symptomatic improvement may take several weeks
- Overdose may cause seizures/arrhythmias
List 4 examples of anti-psychotic drugs. Which ones are:
a) First generation anti-psychotics
b) Atypical anti-psychotics
FIRST GENERATION:
Haloperidol
Chlorpromazine
ATYPICALS:
Olanzapine
Clozapine
Describe the mechanism of action of anti-psychotic drugs. (3)
List 5 indications of anti-psychotic drugs.
MECHANISM OF ACTION:
- Block dopamine receptors; type depends on specific drug:
a. First generation: D1 and D2
b. Atypicals: varying - Dopamine neurotransmission is decreased in mesolimbic and nigrostriatal pathways
a. Improves psychotic symptoms - Anti-histaminergic and anti-cholinergic effect
a. Reduce positive symptoms of schizophrenia
b. Cause sedation and anti-emetic activity
INDICATIONS: Schizophrenia Mania Delusions, hallucinations Behavioural problems Anti-emetic (especially haloperidol)
List 6 common side effects of anti-psychotic drugs.
HINT: there are 3 categories of side effects.
ANTI-HISTAMINERGIC SIDE EFFECTS:
Sedation
ANTI-ADRENERGIC SIDE EFFECTS:
Postural hypotension
Tachycardia
ANTI-CHOLINERGIC SIDE EFFECTS:
Urinary retention
Dry mouth
Blurred vision
Describe the important pharmacokinetics/dynamics of anti-psychotics. (1)
What would you tell the patient when prescribing anti-psychotics? (2)
IMPORTANT PHARMA INFO:
-Affects several receptor systems in CNS
PATIENT INFO:
- Symptoms don’t always disappear while on meds
- Dosage may need to be increased if no improvement is seen
List 3 common examples of benzodiazepines.
Diazepam
Lorazepam
Midazolam
Describe the mechanism of action of benzodiazepines. (2)
What are some common indications for prescribing benzodiazepines? (4)
MECHANISM OF ACTION:
1. Increases GABA affinity for the GABA receptor
- Increased GABA binding to the receptor increases chloride influx through chloride channels
a. This causes hyperpolarisation, causing reduced activity in limbic/thalamic/hypothalamic areas
INDICATIONS: Anxiety Epilepsy Muscle spasm Alcohol withdrawal
Describe the important pharmacokinetics/dynamics for different benzodiazepines. Consider:
a) Diazepam (3)
b) Lorazepam (2)
c) Midazolam (2)
DIAZEPAM:
- Long-acting
- Accumulates if given long term/in liver failure
- Admin: oral, rectal, parenteral
LORAZEPAM:
- Less accumulation
- Admin: oral, parenteral
MODAZOLAM:
- Short-acting
- Admin: parenteral
What would you tell the patient when prescribing benzodiazepines? (2)
PATIENT INFO:
Monitor breathing - report severe breathlessness or palpitations
Risk of addiction - only prescribed short term
