Psychiatry - Pharmacy Flashcards
Psychiatric
Pharmacy
Medication Used in Psychiatry?
- Antidepressants
- Mood stabilisers
- Antipsychotics
- Others
Psychiatric Pharmacy
Antidepressants?
- Selective serotonin reuptake inhibitors (SSRIs) – 1st choice
- Tricyclic antidepressants (TCA)
- Serotonin noradrenaline reuptake inhibitors (SNRI)
- Noradrenergic & specific serotonergic antidepressants (NaSSAs) – mirtazapine
- Noradrenaline reuptake inhibitors (NARI)
- Monoamineoxidase inhibitors (MAOI)
Psychiatric Pharmacy
Antidepressants?
Can be used for other mental health illnesses in addition to depression:
- Panic disorder
- Generalised anxiety disorder
- OCD
- PTSD
Cautious use in those with BPAD
Psychiatric Pharmacy
Anntidepressants - MOA
- Change neurotransmitters levels in the brain
- Certain neurotransmitters (i.e. serotonin and norepinephrine) can improve mood and emotion though how and why is not fully understood
- They treat the symptoms of depression, they do not necessarily address causes - usually used in combination with therapy
- ADx have to be taken for at least 3-4 weeks before they notice any improvement in their symptoms, because increasing the levels of neurotransmitters is a gradual process
Psychiatric Pharmacy
Anntidepressants - MOA
SSRIs
- Work by selectively inhibiting the reuptake of serotonin
- Most widely prescribed type of antidepressants, because they cause fewer side effects. Not addictive!
- An overdose is also less likely to be fatal
- Common side effects of SSRIs include:
- Mainly GI e.g. nausea, abdominal pain, diarrhoea (GI upset)
- Headache
- Insomnia
- Sexual dysfunction
- Anticholingeric - blurred vision, dizziness, sedation, dry mouth
- Insomnia
- Hyponatraemia in elderly
Psychiatric Pharmacy
Anntidepressants - Types of SSRIs
- Fluoxetine
- Citalopram
- Sertraline
- Paroxetine
- Escitalopram
Psychiatric Pharmacy
Antidepressants
Initiation & Discontinuation of SSRIs
- May take a few week to work (trial for at least 4-6 weeks, 6 weeks in older pts, if partial response try for another 2 weeks)
- Stop SSRIs if develop rash and must get help if agitation/suicidal feelings occur
- Patients should be reviewed 1-2 weeks after starting treatment
- After remission of symptoms, continue for at least 4-6 months (12 months in the older patient)
- Maintenance treatment may be needed in those with recurrent depression
Psychiatric Pharmacy
Antidepressants
Serotonin Syndrome
- Occurs within hours of starting SSRI or dose increase
- Restlessness
- Tremor
- Myoclonus
- Confusion
- Headache
- Rapid HR, changes in BP
- Severe cases can be life-threatening – urgent medical attention if high fever, seizures, irregular heartbeat, unconsciousness
Psychiatric Pharmacy
Antidepressants SSRIs
Discontinuation Syndrome
- Irritable/restlessness
- Nausea – “GI chills”
- Paraesthesia
- Ataxia
- Hypomania, anxiety and restlessness
- Reduce the dose gradually over about 4 weeks or so to try to avoid this. In patients who have taken the drug long-term, they may need 6 months or so to withdraw gradually
Psychiatric Pharmacy
Antidepressants
SNRIs
- Newer type of antidepressant
- Works in similar way to SSRIs but reuptake serotonin and noradrenaline
- There are currently two SNRIs prescribed in the UK:
- Venlafaxine
- Duloxetine
- Side effects, cautions and interactions are similar for both SSRIs and SNRIs
Psychiatric Pharmacy
Antidepressants
TCAs
- Older type of antidepressants
- No longer recommended as a first-line treatment
- Can be dangerous if an overdose is taken
- Cause more unpleasant side effects than SSRIs and SNRIs
Psychiatric Pharmacy
Antidepressants
MAOIs
- Older type of antidepressant with a wide range of side effects
- Only to be used if other types of antidepressants are not effective
- Need to avoid certain foods and drinks, such as red wine, older cheeses, pickled fish, which contain a protein called tyramine because consuming tyramine while taking MAOIs can cause a dangerous rise in blood pressure (cheese reaction)
Psychiatric Pharmacy
Antidepressants
Others
- Flupentixol has antidepressant properties when given by mouth in low doses. Flupentixol is also used for the treatment of psychosis
- Mirtazapine a presynaptic alpha2-adrenoreceptor antagonist, increases central noradrenergic and serotonergic neurotransmission. It has few antimuscarinic effects, but causes sedation during initial treatment
Psychiatric Pharmacy
Mood Stabilisers?
- Used to treat bipolar disorder
- They suppress swings between mania and depression
- They are also used in PD and schizoaffective disorder
- The main mood stabilisers are:
- Lithium
- Sodium valproate (as semi-sodium)
- Carbamazepine
- Lamotrigine
- Other drugs used as mood stabilisers:
- Benzodiazepines
- Antipsychotic drugs
Teratogenic!
Psychiatric Pharmacy
Mood Stabilisers?
Lithium
- Lithium is the “classic” mood stabiliser
- Therapeutic drug monitoring is required to ensure lithium levels remain in the therapeutic range: 0.6- 0.8-1.2mmol/L.
- Signs and symptoms of toxicity include nausea, vomiting, diarrhoea, and ataxia (lack of voluntary coordination of muscle movements)
- Side effects are:
- Polyuria/polydipsia
- Lethargy, tremor, sedation
- Weight gain
- Blurred vision
- Hair loss
- Cardiac problems
- Long-term effects: subclinical hypothyroidism
Psychiatric Pharmacy
Mood Stabilisers?
Lithium - Ebstein Anomaly
Psychiatric Pharmacy
Mood Stabilisers?
Sodium Valproate?
- An anticonvulsant medication. Indications – acute mania, acute depressive episodes and prophylaxis of BPAD
- It should be used with caution in people with:
- Decreased kidney function, history of liver disease, long-term inflammation of skin and some internal organs (systemic lupus erythematosus), diabetes
- It shouldn’t be used in people with:
- Active liver disease, personal or family history of severe liver problems, particularly if due to a medicine.
- Hereditary blood disorders called porphyrias.
- Valproate is not recommended for children and adolescents under 18 years of age, as its safety and effectiveness for treating mania have not been studied in this age group.
- Women of childbearing age.
- Most common side effects are;
- Disturbances of the gut such as diarrhoea, nausea, vomiting or abdominal pain
- Increased appetite and weight gain
- Decrease in the number of platelets in the blood (thrombocytopenia).
- Temporary hair loss -– regrowth may be curly*
- Increased alertness
- Aggression
Psychiatric Pharmacy
Mood Stabilisers
Fetal Valproate Syndrome
Psychiatric Pharmacy
Mood Stabilisers
Carbamezapine
- It is an antiepileptic drug
- It may be used under specialist supervision for the prophylaxis of bipolar disorder (manic-depressive disorder) in patients unresponsive to a combination of other prophylactic drugs
- It is used in patients with rapid-cycling manic-depressive illness (4 or more affective episodes per year)
- Side effects: Drowsiness, dizziness, ataxia, nausea, diplopia, rash (5%), agranulocytosis, leucopenia
- Neural tube defects
Psychiatric Pharmacy
Antipsychotics
- Used to treat psychosis
- Mostly used in schizophrenia and bipolar disorder
- Two types:
- 1st generation (typical) - older
- 2nd generation (atypical) - newer
Psychiatric Pharmacy
1st Generation Antipsychotics
They predominantly work by blocking dopamine D2 receptors in the brain:
- Chlorpromazine
- Levomepromazine
- Promazine
- Pericyazine
- Pipotiazine
- Fluphenazine
- Perphenazine
- Prochlorperazine
- Trifluoperazine
- Benperidol
- Haloperidol
- Flupenthixol
- Zuclopenthixol
- Pimozide
- Sulpiride
Psychiatric Pharmacy
1st Generation Antipsychotics
They are not selective for any of the four dopamine pathways in the brain and so can cause a range of side-effects (EPSE):
- parkinsonian symptoms
- dystonia (painful muscular spasms)
- akathisia (restlessness)
- tardive dyskinesia (rhythmic, involuntary movements of tongue, face, and jaw)
Hormonal side-effects (prolactin)
Temperature control (risk of hypothermia)
Antimuscarinic side effects
CVS side-effects and QT prolongation
Sudden death
Over-sedation
Psychiatric Pharmacy
1st Generation Antipsychotics
Dopamine antagonist hypothesis
- The dopamine antagonist hypothesis of antipsychotic drug action is that blocking the action of dopamine at the receptors in the mesolimbic pathway produces an effect on positive psychotic symptoms
- Blockade of dopamine receptors in the nigrostriatal pathway leads to movement disorders similar to Parkinson’s disease. The nigrostriatal pathway extends into the extrapyramidal system of the CNS these side effects are sometimes known as extrapyramidal side effects or EPSEs
- Long term blockade of the receptors in the nigrostriatal pathway can cause them to up-regulate and this can lead to tardive dyskinesia
Psychiatric Pharmacy
2nd Generation Antipsychotics
They act on a range of receptors (mostly 5-HT2A and D2) in comparison to the atypicals and have more distinct clinical profiles, particularly with regard to side-effects:
- Amisulpride
- Olanzapine
- Quetiapine
- Risperidone
- Paliperidone
- Aripiprazole
- Clozapine
Psychiatric Pharmacy
2nd Generation Antipsychotics
- These antipsychotics can increase dopamine selectively in the mesocortical pathway which explains the better effects on negative symptoms
- In the tuberoinfundibular pathway this means that prolactin release is inhibited
- In the striatum this means that atypical antipsychotics do not usually cause EPSEs or tardive dyskinesia
- Blocking the 5HT2A receptors reverses the blockade of the D2 receptors
- There is a reciprocal relationship between serotonin and dopamine, serotonin opposes the release of dopamine in the nigrostriatal and tuberoinfundibular pathways
Psychiatric Pharmacy
2nd Generation Antipsychotics
Clozapine
- Only antipsychotic licensed for treatment resistant schizophrenia
- Evidence that may reduce violence and aggression including suicide
- Can improve tardive dyskinesia and movement disorders
- 2–3% incidence of neutropenia
- Increased risk of seizures at higher doses
- Risk of significant weight gain
- Hypersalivation - can be worse at night
- Risk of diabetes appears to be higher than some other agents
Psychiatric Pharmacy
The Dopamine Hypothesis
Two types of dopamine receptors in the brain:
- First group: Related to emotions and perceptions
- Second group: Muscle tension/function
All conventional antipsychotics block D2 receptors
Too much dopamine in the first group = Psychosis
Not enough dopamine in the second group = Parkinsonism-type side effects (muscle rigidity, bradykinesia, tremor) PLUS akathisia, tardive dyskinesia and dystonia (i.e. due to insufficient dopamine)
Psychiatric Pharmacy
The Dopamine Hypothesis
Dopamine Blockade Effects
Limbic and frontal cortical regions: Antipsychotic effect
Basal ganglia: Extrapyramidal side effects
Hypothalamic-pituitary axis: Hyperprolactinaemia
EPSEs: Parkinsonism
Akathisia
Dystonia
Tardive Dyskinesia
Psychiatric Pharmacy
The Dopamine Hypothesis
Dopamine Blockade Effects
Managing Side Effects
Parkinsonism: Rigidity, tremor, bradykinesia, masklike face:
- Lower antipsychotic dose
- Change to an atypical (i.e. second generation)
- Can give anticholinergic medications eg trihexylphenidine
Akathisia – feeling of inner restlessness:
- Management
- Lower antipsychotic dose
- Change drug
- Try beta blocker or benzo
Psychiatric Pharmacy
The Dopamine Hypothesis
Dopamine Blockade Effects
Neuroleptic Malignant Syndrome
- Life-threatening neurological disorder
- Autonomic dysfunction due to dopamine blockade
- Rare but often fatal adverse reaction – 90% cases occur within 10 days of initiating a neuroleptic drug
- Dyspnoea, dysphagia and difficulty mobilising, then pyrexia, muscle rigidity, hypo/hypertension, tachycardia, delirium, coma
- Elevated creatinine phosphokinase
Psychiatric Pharmacy
Other Psychiatric Drugs
Benzodiazepines
- Benzodiazepines are indicated for the short-term relief of severe anxiety or agitation
- Long-term use should be avoided
- Diazepam, alprazolam, chlordiazepoxide, and clobazam have a sustained action, can cause “hangover” effect
- Shorter-acting compounds such as lorazepam and oxazepam may be preferred but they carry a greater risk of withdrawal symptoms
*
Psychiatric Pharmacy
Other Psychiatric Drugs
Antimuscarinics
Hyoscine
Pirenzepine
Procyclidine
Orphenadrine
Trihexyphenidyl
- Used to treat muscarinic side effects of antipsychotics and EPSEs
- Side-effects of antimuscarinics include constipation, dry mouth, nausea, vomiting, tachycardia, dizziness, confusion, euphoria, hallucinations, impaired memory, anxiety, restlessness, urinary retention, blurred vision, and rash. Angle-closure glaucoma occurs very rarely
