25.2 Drugs in the management of mental health disorders Flashcards

1
Q

What is psychosis?

A

A mental state characterised by a loss of touch with reality.
A psychotic illness is characterised by multiple symptoms affecting thought, perceptions, emotions and volition.

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2
Q

What are neuroleptics?

A

Aka. antipsychotics.
Used to treat psychoses.

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3
Q

What is the difference between acute and chronic schizophrenia?

A

Schizophrenia is one of the main conditions associated with psychosis.
- Acute: positive symptoms aka. delusions, hallucinations, abnormal thought processes.
- Chronic: negative symptoms aka. poverty of speech, anhedonia, apathy, attention impairment.

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4
Q

Which neurotransmitters are involved in schizophrenia?

A
  • Dopamine
  • 5-HT (serotonin)
  • GABA
  • Glutamate
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5
Q

What are the 2 antipsychotic drug groups?

A

EPEs also called Parkinsonisms

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6
Q

Describe the 1st generation (typical) antipsychotics.

A

Great affinity for D2 receptors.
Dopamine receptor antagonists.
- Phenothiazines e.g. trifluoperazine
- Butyrophenones

Poor for -ve symptoms.
Also have effects on adrenoreceptors, muscarinic receptors and histamine receptors. Leading to adverse effects.

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7
Q

Describe the 2nd generation (atypical) antipsychotics.

A

Serotonin-dopamine antagonists.
- Benzodiazepine derivatives e.g. clozapine, quetiapine
- Substituted benzamides e.g. sulpiride

Fewer adverse effects.

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8
Q

What risks are associated with clozapine?

A
  • Significant toxicity
  • Can have haematological consequences
  • Can cause myocarditis and cardiomyopathy (usually develops within first 2 months of treatment)
  • Presents as sinus tachycardia
  • Treatment must be stopped
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9
Q

Name 8 adverse effects of neuroleptics.

A
  • Acute neurological effects: acute dystonia (e.g. lip smakcing, muscle spasm), Parkinsonism
  • Chronic neurological effects: tardive dyskinesia, dystonia
  • Neuroendocrine effects: amenorrhoae, galactorrhoea
  • Anticholinergic effects: xerostomia, constipation, blurred vision, urinary retention
  • Antihistaminergic: drowsiness, sedative effects
  • Antiadrenergic: hypotension, arrythmias
  • Cardiac toxicity
  • NMS (neuroleptic malignant syndrome)
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10
Q

Explain the cardiac toxicity of antipsychotics.

A
  • Antipsychotic drugs delay cardiac repolarisation leading to ventricular arrythmias
  • Prolonged QT interval, risk of condition developing called Torsade de Pointes
  • Can result in syncope
  • Can degenerate into ventricular fibrillation resulting in sudden cardiac death

Olanzapine and risperidone are associated with an increased risk of stroke in the elderly.

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11
Q

Explain NMS.

A

Neuroleptic malignant syndrome
- Rare idiosyncratic reaction to neuroleptics
- Most serious neuroleptic adverse effect
- If untreated, 20% mortality risk
- Symptoms: hyperthermia, fluctuating consciousness, muscles rigidity, tachycardia, sweating
- Treatment: diazepam, bromocriptine, supportive care

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12
Q

When do NICE recommend the use of atypical antipsychotics?

A
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13
Q

What are antidepressants used to treat?

A
  • Major depressive disorder
  • Bipolar depressive disorder
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14
Q

What are the biologic signs of depression?

A
  • Fatigue
  • Apathy
  • Poor concentration
  • Changes in appetite
  • Changes in sleep pattern
  • Low libido
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15
Q

What is the monoamine hypothesis of depression?

A

Depression is caused by a funcitonal defecit in monoamine neurotransmitters: noradrenaline and 5HT (serotonin).

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16
Q

Describe the action of tricylclic antidepressants and SSRIs.

A
  • Tricyclics: prevent reuptake of noradrenaline and serotonin in the neuron
  • SSRIs: prevent reuptake of serotonin making more available for transmission

Ultimately making more dopamine and serotonin available in the postsynaptic space.

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17
Q

What does SSRI stand for?

A

Selective serotonin reuptake inhibitors.

18
Q

Do patients respond immediately to increases in monoamine neurotransmitters?

A

No, drug efficacy may require down regulation of receptors which does not occur immediately.
Antidepressants can make pts feel worse before they feel better.

19
Q

What are the 4 categories of antidepressants?

A
  • Tricyclic antidepressants
  • SSRIs
  • Monoamine oxidase inhibitors
  • Others
20
Q

Describe tricyclic antidepressants.

A
  • Block noradrenaline and serotonin reuptake
  • Extremely toxic in overdose, high risk of mortality, not recommended for first choice medication
  • Causes cardiac toxicity in overdose
  • Can prolong QT interval
  • E.g. amitryptiline, imipramine, clomipramine
21
Q

What receptors do tricyclic antidepressants have some affinitiy for?

A
  • Muscarinic cholinergic receptors, causes dry mouth as a side effect
  • Adrenoreceptors causing postural hypotension in some patients
  • Histamine 1 receptors which can cause sexual dysfunction and loss of libido
22
Q

Describe SSRIs.

A
  • Block serotonin reuptake
  • E.g. setraline, fluoxetine, citalopram, paroxetine
  • Adverse effects: nausea, diarrhoea, sexual dysfunction, insomnia and agitation
  • Interactions: cytochrome P450 inhibitors (e.g. antifungals and erythromycin)
23
Q

Describe monoamine oxidase inhibitors.

A
  • E.g. phenelzine and moclobemide
  • Inhibit monoamine oxidase enzymes (the enzymes responsible for breakdown of monoamine neurotransmitters)
  • Historical MAOIs: “The Cheese Reaction” old MAOIs were non-selective, blocked gut enzymes causing tyramine to be absorbed into the body leading to hypertensive crisis, headache, tachycardia arrythmias and stroke
  • Newer MAOIs are selective and are selective for MOA-A which is found in the CNS only
24
Q

Name the “other antidepressants”.

A

Don’t fit into a specific group:
- Mirtazapine
- Venlafaxine
- Bupropion
- Nefazodone and trazodone

25
Q

What is St John’s wort?

A
  • Unlicensed herbal remedy for the treatment of mild depression
  • Can induce hepatic enzyme
  • Well recognised important drug interactions e.g. warfarin, simvastatin, oral contraceptive pill
  • Take thorough drug history including herbal medication
26
Q

What are the 3 main drugs used in the treatment of bipolar disorders?

A
  • Lithium prophylaxis
  • Sodium valproate (mood stabilising effects)
  • Carbamazepine for prophylaxis of manic episodes in pts unresponsive to lithium
27
Q

When must sodium valproate be avoided?

A

In women or girls of childbearing potential unless they’re on the pregnancy prevention programme

28
Q

Describe lithium prophylaxis in the treatment of bipolar disorders.

A
  • Requires regular therapeutic monitoring
  • Therapeutic range is 0.4-1.2mmol/l
  • Renal excretion
29
Q

What are the possible adverse effects of lithium?

A
  • Fatigue, nervousness, GI disturbances, weight gain, oedema
  • May damage the distal renal tubule resulting in nephrogenic diabetes
  • Maybe hypokalaemia and occasionally hypercalcaemia
  • Can disturb thyroid hormone synthesis resulting in hypo or hyper thyroidism
  • Can prolong QT interval
  • Long term use can result in memory impairment or osteoporosis
30
Q

What is lithium toxicity?

A
  • Occurs in overdose or when co-prescribed with interacting drugs
  • Leads to reduced renal excretion of lithium = cardiac and neurological toxicity, eventually leads to coma and death if untreated
31
Q

What drugs are contraindicated in patients taking lithium?

A
  • NSAIDs
  • Diuretics
  • ACE inhibitors
32
Q

What drugs are used to treat attention deficit hyperactivity disorder?

A

Central nervous stimulants amphetamine type and related drugs.
- ‘Paradoxical effects’ in children
- Requires specialist initiation
- E.g. Methylphenidate and Atomoxetine

33
Q

When are beta-blockers used in mental health conditions?

A

Used to reduce the autonomic symptoms of anxiety (tremor, sweating, reduces heart rate).
For the physical symptoms of anxiety, not the psychological.

34
Q

Name some benzodiazepines.

A
  • Diazepam (Valium)
  • Midazolam (used in dentistry for conscious sedation)
  • Lorazepam

Benzos are also used recreationally, addictive.

35
Q

What are the major uses of benzodiazepines?

A

A: anixolytics
M: muscle relaxants
A: anti convulsants
I: IV anaesthetics
S: sedatives

36
Q

Describe the pharmacology of benzodiazepines.

A
  • Benzos are CNS depressants
  • Act by potnetiating the actions of GABA, the primary inhibitory neurotransmitter of the CNS
37
Q

How are benzos metabolised?

A

Predominantly by the liver.

38
Q

How do the half-lives of benzos vary?

A

Midazolam half life = 2-4 hours (sedation)
Diazepam half life = 20-40 hours

39
Q

What is the antagonist for benzodiazepine overdose?

A

Flumazenil
- Reverses the sedative effects of benzos when used in anaesthesia
- Not used to reverse overdose, only reverses sedative effects

40
Q

What are the possible adverse effects of benzodiazepines?

A
  • Normal doses: drowsiness, sedation, dizziness, slurred speech, impaired cognitive function and memory impairment
  • Can cause paradoxical hyperactivity in children
  • Can cause disinhibition and aggression is some adults
  • Dependency and withdrawal symptoms may occur when benzodiazepines are discontinued abruptly after more than 4 weeks of use
  • Withdrawal can cause: anxiety, seizures, insomnia, nightmares, headaches