Agitation, psychomotor Flashcards
1
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Common indications
A
- Prophylaxis and treatment of nausea and vomiting in a wide range of conditions, particularly when due to vertigo. However, due to their side effect profile, other antiemetic classes are usually preferable
- Psychotic disorders, such as schizophrenia, where they are used as first-generation (typical) antipsychotics
2
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
MOA
A
- N&V is triggered by a variety of factors, including gut irritation, drugs, motion and vestibular disorders, as well as higher stimuli (sight, smells, emotions)
- The various pathways converge on a ‘vomiting centre’ in the medulla, which recieves inputs from the CTZ, the solitary tract nucleus (which is innervated by the vagus nerve), the vestibular system and higher neurological centres
- The antiemetic properties of phenothiazines arise from blockade of various receptors, including dopamine (D2) receptors in the CTZ and gut and, to a lesser extent, histamine (H1) and acetylcholine receptors in the vomiting centre and vestibular system
- This makes them effective for N&V in a wide range of situations, including chemotherapy, radiotherapy and vertigo
3
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Important adverse effects
A
- Drowsiness and postural hypotension are relatively common with phenothiazines
- Movement abnormalities, termed extrapyramidal syndromes, are a major drawback of their use
- They arise from D2 receptors blockade via the same mechanism as for other first-generation (typical) antipsychotics
- In the context of short-term treatment for N&V, this is most likely to take the form of an acute dsytonic reaction such as oculogyric crisis
- In longer-term treatment (which is more likely when they are used as an antipsychotic), other extrapyramidal syndromes such as tardive dyskinesia may occur
- Like all antipsychotics, phenothiazines can cause QT-interval prolongation
4
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Warnings
A
- Due to their sedative effect and potential for hepatotoxicity, these drugs should be avoided in patients with severe liver disease
- They should also be avoided in patients susceptible to anticholinergic side effects, such as those with prostatic hypertrophy (who may develop urinary retention)
- Doses should be reduced in the elderly
5
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Important interaction
A
- You should consult the BNF when prescribing for a patient taking these drugs as there is an extensive list of interactions
- Prominent among these are drugs that prolong the QT interval, such as antipsychotics, amiodarone, ciprofloxacin, macrolides, quinine and SSRIs
6
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Prescription
A
- We would suggest you seek senior or specialist advice when contemplating the prescription of a phenothiazine, as other drugs should usually be tried first
- A typical prescription in the context of N&V might be for prochlorperazine 20mg OD or 12.5mg IM to settle the acute attack, with further oral doses (e.g. 10mg 12-hrly) prescribed if necessary for ongoing symptoms
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7
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Administration
A
- Intramuscular prochlorperazine should be administered by deep injection in a large muscle
8
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Communication
A
- Explain that you are offering an anti-sickness medicine
- Although it is generally effective, it does not work for everyone and a second or different medicine may be necessary
- Ask them to let you know if they do not achieve satisfactory relief
- Discuss the potential for drowsiness (and its implications for driving) and dizziness and standing
- Ask them to stop taking the medicine and seek medical advice if they develop any muscle spasms or movement abnormalities
9
Q
(Antiemetics) Phenothiazines- prochlorperazine, chlorpromazine
Monitoring
A
- Resolution of symptoms is the best guide to efficacy, in prolonged use you should monitor the patient for extrapyramidal features, as these may be subtle (e.g. an increased tendency to falls) and their relationship to the drug may not be obvious to patients or other HCP
10
Q
Antipsychotic (first-generation- typical) HALOPERIDOL, CHLORPROMAZINE, PROCHLORPERAZINE
common indications
A
- Urgent treatment of severe psychomotor agitation that is causing dangerous or violent behaviour, or calming patients to permit assessment
- Schizophrenia, particularly when the metabolic side effects of second-generation (atypical) antipsychotics are likely to be problematic
- Bipolar disorder, particularly in acute episodes of mania or hypomania
- Nausea and vomiting, particularly in the palliative care setting
11
Q
Antipsychotic (first-generation- typical) HALOPERIDOL, CHLORPROMAZINE, PROCHLORPERAZINE
MOA
A
- Antipsychotic drugs block post-synaptic dopamine D2-receptors.
- There are three main dopaminergic pathways in the central nervous system
- The mesolimbic/mesocortical pathway runs between the midbrain and the limbic system/frontal cortex
- D2 blockade in this pathway is probably the main determinant of antipsychotic effect, but this is incompletely understood
- The nigrostriatal pathway connects the substantia nigra with the corpus striatum of the basal ganglia
- The tuberohypophyseal pathway connects the hypothalamus with the pituitary gland
- D2 receptors are also found in the CTZ, where blockade accounts for their use in N&V
- All antipsychotics, but particularly chlorpromazine, have some sedative effect
- This may be beneficial in the context of acute psychomotor agitation
12
Q
Antipsychotic (first-generation- typical) HALOPERIDOL, CHLORPROMAZINE, PROCHLORPERAZINE
Important adverse effects
A
- Extrapyr.amidal effects- movement abnormalities that arise from D2 blockade in the nigrostriatal pathway- are the main drawback of first-generation antipsychotics
- They take several forms: acute dystonic reactions are involuntary parkinsonian movements or muscle spasm; akathisia is a state of inner restlessnes, andd the neuroleptic malignant syndrome is rare but life-threatening side effect characterised by rigidity, confusion, autonomic dysregulation and pyrexia
- These all tend to occur early in treatment, by contrast, tardive dyskinesia is a late adverse effect (tardive, late), occurring after months or years of therapy
- This comprises movements that are pointless, involuntary and repetitive (e.g. lip smacking)
- It is disabling and may not resolve on stopping treatment. Other adverse effects include Drowsiness, hypotension, QT-interval prolongation, ED and hyperprolactinaemia due to tuberophypophyseal D2-blockade
- (e.g. mentrual disturbance, galactorrhoea and breast pain)
13
Q
Antipsychotic (first-generation- typical) HALOPERIDOL, CHLORPROMAZINE, PROCHLORPERAZINE
Warnings
A
- Elderly patients are particularly sensitive to antipsychotics, so start with lower doses. Antipsychotics should ideally be avoided in dementia, as they may increase the risk of death and stroke
- They should be avoided if possible in Parkinson’s disease due to their extrapyramidal effects
14
Q
Antipsychotic (first-generation- typical) HALOPERIDOL, CHLORPROMAZINE, PROCHLORPERAZINE
Important interactions
A
- Consultant the BNF when prescribing for a patient taking antipsychotics as there is an extensive list of interactions
- Prominent among these are drugs that prolong the QT interval (e.g. amiodarone, macrolides)
15
Q
Antipsychotic (first-generation- typical) HALOPERIDOL, CHLORPROMAZINE, PROCHLORPERAZINE
Prescription
A
- Regular treatment is required to treat schizophrenia and should only be started or adjusted under the guidance of a psychiatrist
- A single dose may be used to control acute or violent behaviour
- A common choice is haloperidol 0.5-3.0mg IM, although higher doses may be used in extreme cases
- This should be given only under the guidance of an appropriately experienced clinicians
- For the control of nausea, haloperidol is used in regular small oral or SC doses (e.g. 1.5mg at night) or as a component of a continuous SC infusion
