Neuropharmacology Flashcards
ANTYPSYCHOTICS
highest weight gain and cardiometabolic risk drugs
- FGAs: Chlorpromazine
- SGAs: “The PINEs”: Olanzapine, Clozapine, Quetiapine
ANTYPSYCHOTICS
Which SGA has the highest risk of developing DM 2
Olanzapine
ANTYPSYCHOTICS
parameters to monitor in prevention of cardiometabolic adverse effects
Monitor all patients
Monitoring parameters should consist of:
– weight, BMI, and waist circumference
– blood pressure
– fasting blood glucose concentrations
– full lipid profile (triglycerides, total cholesterol, HDL-C, LDL-C)
ANTIPSYCHOTICS
Cardiometabolic adverse effects Monitoring, when??
- baseline
- 3-monthly for the first year
- 6-monthly for the duration of therapy
“Metabolic Syndrome”
Definition
INCREASED WAIST CIRCUMFERENCE
+
ANY TWO of the following factors:
- reduced (HDL-C) levels
- raised triglyceride levels
- hypertension
- hyperglycaemia
ANTIPSYCHOTICS
Which drugs can be affected by Tobacco, why, and how to manage
Olanzapine & Clozapine
- SMOKING = reduces serum levels (inducer) => increase doses
- smoking cessation = increases serum levels => dose reduction
ANTIPSYCHOTICS
Which drugs are MORE likely to cause Hyperprolactemia
- FGAs = ALL
- SGAs = amisulpride & risperidone
ANTIPSYCHOTICS
Which drugs are LESS likely to cause Hyperprolactemia
- Aripiprazole
- Clozapine
ANTIPSYCHOTICS
What is the plasma concentration of Prolactin that defines drug-induced Hyperprolactemia
Hyperprolactinemia (>2000 mIU/L)
values > 5000mIU/L are more likely due to a prolactinoma
ANTIPSYCHOTICS
Hyperprolactemia
Signs & Symptoms
- galactorrhea
- gynaecomastia
- sexual dysfunction (decreased libido, impaired sexual arousal, impotence and anorgasmia)
- infertility (novulation, impaired spermatogenesis)
- amenorrhoea
- reduction in bone mineral density (which is of concern in young people who have not yet reached their peak bone mass and in patients with osteoporosis)
ANTIPSYCHOTICS
less-sedating drugs
- Haloperidol
- Aripiprazole
- Amisulpride
ANTIPSYCHOTICS
most sedating SGA drugs
“The PINEs”
- olanzapine
- Clozapine
- Quetiapine
QTc normal ranges
- Men: 350–450 ms
- Women: 360–460 ms
ANTIPSYCHOTICS
QT prolongation
- FGAs: All in general
- SGAs: all, but Clozapine has is most commonly associated
ANTIPSYCHOTICS
Most common Anticholinergic effects
“Hot & Dry”
- Hyperthermia
- Decreased secretions (dry mouth)
+
- Tachycardia
- sedation
- urinary retention
- glaucoma
ANTIPSYCHOTICS
Which antipsychotic has the highest anticholinergic effects?
Clozapine
ANTIPSYCHOTICS
What is Clozapine unique adverse effect profile
Agranulocytosis (recurrent infections)
+
Cardiomyopathy
ANTIPSYCHOTICS
How to monitor for Agranulocytosis caused by Cloxapine
- WEEKLY WBC and neutrophil counts for at least the first 18 weeks
- MONTHLY after initial period, if no complication
ANTIPSYCHOTICS
WBC count and Neutropenia
MILD range values and Management
WBC >3.500
AND
NC >2.000
⬇︎
Clozapine therapy can continue
ANTIPSYCHOTICS
WBC count and Neutropenia
MODERATE range values and Management
WBC 3.000 - 3.500
AND/OR
NC 1.500 - 2.000
⬇︎
Requires increasing frequency of monitoring, to twice weekly
ANTIPSYCHOTICS
WBC count and Neutropenia
SEVERE range values and Management
WBC < 3.000
AND/OR
NC < 1.500
⬇︎
- CEASE clozapine immediately
- Daily CBC
- patient in protective isolation
- Contact Consultant Psychiatrist and arrange urgent medical review
- Clozapine may be restarted if Agranulocytosis resolved
ANTIPSYCHOTICS
How to monitor for Cardiomyopathy caused by Cloxapine
- WEEKLY Troponins and C-reactive protein for the first 4 weeks
- body temperature, pulse rate, BP and RR at baseline
- (ECG) echocardiogram, are recommended at baseline and should be repeated on the basis of the other observations and results
ANTIPSYCHOTICS
which drugs are more commonly associated with Movement Disorders (EPS)?
FGAs
ANTIPSYCHOTICS
Which are the moviment disorders associated with Antipsychotics?
“AdAPT”
- Acute Dystonia
- Akathisia
- Parkinsonism
- Tardive Dyskinesia
https://australianprescriber.tg.org.au/articles/the-management-of-acute-dystonic-reactions.html
ANTIPSYCHOTICS
Acute Dystonia onset
Sudden (min-days)
ANTIPSYCHOTICS
Acute Dystonia Sx
- Twisting movements
– Oculogyric crisis
– Buccolingual crisis
– Blepharospasm - Abnormal postures
– Torticollis
– Opsthotonos
ANTIPSYCHOTICS
Acute Dystonia Mx
Benztropine (IV or IM)
ANTIPSYCHOTICS
Akathisia onset
Days - months
ANTIPSYCHOTICS
Akathisia Sx
abnormal, uncomfortable sensation of restlessness combined with an urge to move about
ANTIPSYCHOTICS
Akathisia Mx
FIRST LINE : propranolol VO
(avoided in asthma, severe peripheral vascular disease and CHF)
SECOND LINE: diazepam VO
ANTIPSYCHOTICS
Parkinsonism Onset
Gradual
(early weeks)
ANTIPSYCHOTICS
Parkinsonism Sx
- Resting tremor
- Muscle rigidity
- Bradykinesia
ANTIPSYCHOTICS
Parkinsonism Mx
- Benztropine VO
ANTIPSYCHOTICS
Tardive Dykinesia (TD) onset
- gradual onset after prolong therapy (> 6 months)
- can also be seen when withdrawing an atipsychotic
ANTIPSYCHOTICS
Tardive Disknesia Sx
uncontrolled involuntary movements
- grimacing
- lip smacking
- Rapid eye blinkning
- rapid eye movement
- tongue protruse
- lip puckering and pursing
- choreifomr movements of limbs and trrunks
ANTIPSYCHOTICS
Tardive Disknesia Mx
Switch to CLOZAPINE
Symptoms tend to improve with 3 months after stopping the drug
ANTIPSYCHOTICS
Drugs that can Cause of Neuroleptic Malignant Syndrome (NMS)
- Most commonly associated with anti-psychotics (Dopamine antagonists)
- anti-emetics (eg domperidone, metoclopramide)
- cessation of a dopamine agonist
ANTIPSYCHOTICS
Neuroleptic malignant syndrome (NMS) Cause
lethal adverse effect from treatment with a drug that affects dopaminergic transmission (↓DA)
- Antipsychotics (LEADING CAUSE)
- antidepressants
- antiemetic drugs
- lithium
- after the cessation of dopamine agonist drugs (Parkinson’s)
ANTIPSYCHOTICS
Neuroleptic malignant syndrome (NMS) Diagnostic criteria
-
GRADUAL ONSET
-severe muscle rigidity (bradykinesia/hyporeflexia) - increased temperature (VERY HIGH FEVER)
- autonomic instability (diaphoresis, elevated or labile blood pressure, tachycardia, tachypnoea, no occular clonus or mydriasis)
- no GI tract symptoms
- Alltered Mental Status (delirium)
- raised creatine kinase (CK)
ANTIPSYCHOTICS
Neuroleptic malignant syndrome (NMS) Mx
- cessation of dopamine antagonists
- Respiratory and circulatory support (muscle rigidity involving the chest wall)
- Aggressive fluid replacement for hypotension
should be given fluid replacement -
Cooling for hyperthermia If temp. > 39 °C
– the patient should be cooled with tepid sponging and ice packs. Antipyretic drugs are ineffective - Sedation - LORAZEPAM
- Antidotal therapy = BROMOCRIPTINE (a dopamine agonist)
- DANTROLENE - muscle rigidity
Bromocriptine should be titrated to clinical effect, looking for a lowering of the temperature and reduction of muscle rigidity.
ANTIDEPRESSANTS
Long acting SSRI
Fluoxetine
ANTIDEPRESSANTS
Best choice in post-MI patients with depression
Fluoxetine
ANTIDEPRESSANTS
SSRIs/SNRIs drug interaction mechanism
SSRIs are substracts for metabolism by CYP450 system
Although SSRIs/SNRIs aren’t inducer or inhibitoirs of the CYP450 system, they can inhibit the metabolic clearance of other drugs (eg benzodiazepines, warfarin, clozapine) increasing their circulation concentration. this occurs because of the SRS drugs competition with other drugs for metabolism by the CYP450 system.
ANTIDEPRESSANTS
Which SSRIs/SNRIs carries the least drug interaction risk
- Escitalopram
- Sertraline
ANTIDEPRESSANTS
SSRIs -
risk of BLEEDING
SSRIs block the uptake of serotonin into platelets
The risk is increased by:
- concurrent use of NSAIDs
- concurrent use of anticoagulant drugs and antiplatelet drugs
- Patients with liver cirrhosis or liver failure
- patients susceptible to gastrointestinal bleeding
(eg patients with a history of peptic ulcer disease or
oesophageal varices, or who are undergoing surgery)
ANTIDEPRESSANTS
SSRIs -
management if risk of BLEEDING
- Consider an alternative class of antidepressant
- consider addition of a gastroprotective drug (eg PPI)
- If NSAID use must be continued, a less gastrotoxic NSAID is recommended (eg ibuprofen, diclofenac).
ANTIDEPRESSANTS
SSRIs - what drugs have the highest risk of SEDATION/PSYCHOMOTOR IMPAIRMENT
- Fluvoxamine
- Paroxetine
ANTIDEPRESSANTS
SSRIs - menagement of SEDATION/PSYCHOMOTOR IMPAIRMENT
- tolerance develops over a period of days
- Commencing treatment at a lower dose and increasing the dose slowly reduces the degree of sedation.
- Avoid concomitant use of other CNS depressants (eg alcohol, benzodiazepines).
ANTIDEPRESSANTS
Citalopram notable adverse effect
QT prolongation
(it is dose related)
ANTIDEPRESSANTS
Drugs that can induce Hyponatraemia?
- SSRIs
- SNRIs
- TCAs
- MAOIs
ANTIDEPRESSANTS
Risk factors for Hyponatraemia with concurrent use of Antidepressives?
- older age
- female gender
- low body weight
- drug interaction (eg diuretics, NSAIDs, carbamazepine, chemotherapy)
- impaired renal function
- comorbidity (eg hypothyroidism, diabetes, chronic obstructive pulmonary disease, hypertension, stroke, head injury)
- hot weather.
ANTIDEPRESSANTS
Prevention of Hyponatraemia & management
serum sodium may be considered in patients at high risk of hyponatraemia approximately 3 to 4 weeks after initiating treatment
If hyponatraemia occurs, discontinuation of the causative drug normalises serum sodium concentration within 2 weeks.
ANTIDEPRESSANTS
Drugs that cause Sexual Dysfunction
- SSRIs
- SNRIs
- TCAs
ATIDEPRESSANTS
Which SSRIs are associated with the highest risk of sexual dysfunction?
Paroxetine and sertraline
ANTIDEPRESSANTS
Drugs with minimal to negligeable Sexual Dysfunction
- MAOIs
- Bupropion
- Mirtazpine
ANTIDEPRESSANTS
antidepressant- induced sexual dysfunction Mx
- Consider other causes
( alcohol use, diabetes, atherosclerosis, cardiac disease, central and peripheral nervous system conditions, medication) - Wait
(remits spontaneously over time as patient develops tolerance = Consider this approach for patients with mild sexual dysfunction) - Reduce dose
(considered if the condition being treated is well controlled) - Switching between the same class
(Paroxetine and Setraline have the highest risk) - Switching to an antidepressant with less risk of sexual dysfunction
– Mirtazapine
– Bupropion ( not subsidesed through the PBS) = better option in females - Adjunctive treatment
(with the addition of a non- antidepressant adjunctive treatment would be most reasonable for patients who have obtained substantial clinical benefit from the implicated antidepressant, and where sexual dysfunction is of moderate severity)
– Sildenafil or Tadalafil - Non-pharmacological treatments
– CBT and couples therapy
– Exercise before sexual activity
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.mja.com.au/system/files/issues/212_07/mja250522.pdf
ANTIDEPRESSANTS
Mirtazapine notable side effects
- waight gain
- Sedation
- Priapism
ANTIDEPRESSANTS
TCA’s
Side effecrs
- anticholinergic side effects (dry mouth, urinary retention, and dry skin)
- QT prolongation (cardiotoxic)
- Weigh gain
- Sedation
Nortriptylinene has lower incidence of these side effects
ANTIDEPRESSANTS
MAOIs interacts with which compound found in some drugs and foods?
Tyramine
ANTIDEPRESSANTS
What can the interaction of MAOIs and Tryamine cause?
Hypertensive Crisis
ANTIDEPRESSANTS
what drugs and foods contain Tyramine?
- Drugs: TCAs
- Foods:
– matured, aged or out-of-date cheese
– liver products (eg pâté);
– fermented, matured or aged meat (eg salami,
pepperoni, mortadella);
– pickled herring;
– improperly stored or spoilt meat, fish, poultry or eggs
– fava or broad bean pods (not beans),
– banana peel
– all tap and home-brewed beers
ANTIDEPRESSANTS
Bupropion contraindication
in patients suffering from seizures
it reduces seizure threshold
ANTIDEPRESSANTS
Venlafaxine contraindication
- Diastolic Hypertension
- Breast feeding
ANTIDEPRESSANTS
Drugs associated with Serotonin Syndrome
- SSRIs
- SNRIs
- TCAs
- MAOIs
- 1st generation Antihistamines
- Amphetamines
- MDMA
- Lithium
- Tryptophan
- St John’s Wort with antidepressant
ANTIDEPRESSANTS
Serotonin toxidrome
Clinical presentation
- onset within hours of commencing the serotonergic agent or interacting drugs
TRIAD of clinical effects:
-
neuromuscular clonyc excitation
—hyperreflexia, clonus (inducible or spontaneous), ocular clonus, myoclonus, shivering, tremor, hypertonia or rigidity - autonomic effects
—hyperthermia (mild: < 38.5 °C; severe: > 38.5 °C or rapidly rising), diaphoresis, flushing, mydriasis, tachycardia
—GI tract symptoms (nausea & vomiting, diarrhoea, increased bowel sounds) - central nervous system (CNS) effects
—agitation, anxiety, confusion, seizure
ANTIDEPRESSANTS
Serotonin toxicity Mx
- cease inciting agent(s)
- if mild to moderate serotonin toxicity
– treatment is not usually required - If severe
– sedation + intubation + paralysion
– temperature control - If significant neuromuscular agitation = Cyproheptadine VO
– In patients with severe serotonin toxicity who are unable to take oral medications, Chlorpromazine IV may be used
ANTIDEPRESSANTS
Saint John’s Wort combined with COCP
- SJW reduces the effectiveness of COCs and increases the risk of unintended pregnancy
SJW’s extracts induce the cytochrome P450 enzymes and increase intestinal P-glycoprotein expression. This stimulating the liver to break down the oestrogen and progestogen more rapidly, making COCs less effective and increasing chance of unintended pregnancy
ANTIDEPRESSANTS
Saint John’s Wort combined with Warfarin
SJW reduces the effectiveness of warfarin and increases the risk of stroke, ischaemia, arterial blockage etc.
- SJW’s extracts induce the cytochrome P450 enzymes, therefore metabolising warfarin at a faster rate therefore decreasing its effectiveness.
MOOD STABILISER
common adverse effects seen in chronic use of Lithium
“LitHIUm”
- Low thiroid (Hypothyroidism)
- Heart (Ebstein anomaly)
- Insipidus (Nephrogenic Diabetes insipidus)
- Unwanted movements
+
- Alopecia/hair thining
- Acne
Lithium per si doesn’t cause kidney injury or affect clearance
MOOD STABILISER
Most common setting of Lithium toxicity
Chronic usage
Acute lithium poisoning rarely leads to significant toxicity due to:
- the rapid elimination by the kidneys
- slow uptake into the CNS
Acute ingestions of < 25 g lithium are unlikely to cause major effects
unless patients have kidney failure.
In acute lithium poisoning, patients may have a concentration greater than 5 mmol/L and yet this may not indicate severe poisoning.
MOOD STABILISER
Risk factors for chronic lithium poisoning
- change in dose
- decreased elimination (kidney function impairment)
- dehydration
- age > 50 years
- drug interactions ((notably [NSAIDs], diuretics, ACEis/ARBs))
- nephrogenic
- diabetes insipidus
- thyroid dysfunction.
MOOD STABILISER
Clinical presentation
- gastrointestinal effects
—nausea, vomiting and diarrhoea - CNS effects
—tremor, hyperreflexia, ataxia and dysarthria in mild to moderate toxicity;
—confusion, coma and seizures in severe toxicity - cardiovascular effects
— QT prolongation and hypotension in severe cases.
MOOD STABILISER
Key investigations in lithium poisoning
- ECG
— QT prolongation occurs with severe poisoning, but rarely results in arrhythmias. - Lithium concentration
- Creatinine and urea
—check kidney function.
MOOD STABILISER
Lithium toxic concentration
In chronic lithium poisoning, a concentration > 2 mmol/L is associated with severe poisoning.
Lithium concentrations can be difficult to interpret, and the lithium concentration in blood only reflects the
concentration in the CNS in chronic poisoning.
MOOD STABILISER
Acute Lithium poisoning Mx
Most patients with acute poisoning require no specific treatment except:
- All patients with chronic lithium toxicity require admission.
- serial measurement of lithium concentrations to confirm elimination.
- fluid replacement (essential in all patients with lithium poisoning)
MOOD STABILISER
Chronic poisoning Mx
SIMILAR INITIAL MANAGEMENT
- All patients with chronic lithium toxicity require admission.
- serial measurement of lithium concentrations to confirm elimination.
- fluid replacement (essential in all patients with lithium poisoning)
Intravenous fluid therapy with NaCl 0.9% is the first-line treatment and increases lithium elimination in patients with normal kidney function.
Many patients on long-term lithium therapy have diabetes insipidus, so it is essential that this is taken into
consideration when giving intravenous fluids (ie larger fluid requirements to replace increased urine output).
MOOD STABILISER
Is activated charcoal used in the management of ACUTE Lithium poisoning?
NO
Activated charcoal does not bind lithium.
MOOD STABILISER
What amount of lithium ingested would indicate decontamination
> 50 g
MOOD STABILISER
What type of decontamination would be indicated in massive Lithium poisoning and what criteria shoulb met
whole bowel irrigation
- if given within the first 6 hours
- patient is awake and cooperative
MOOD STABILISER
Indications for Haemodyalisis in Lithium poisoning
- lithium concentration > 2.5 mmol/L (in chronic intake)
- severe clinical effects —delirium, seizures, coma or hypotension
- lithium concentration > 1.5 mmol/L associated with
— persistent clinical effects
— little response to intravenous fluids
— persistent kidney impairment despite fluids.
MOOD STABILISER
when to stop Dyalisis in lithum poisoning
Dialysis should be continued until lithium concentrations < 1 mmol/L
Lithium clearance is proportional to flow rate, so either haemodialysis or high-flux continuous veno-venous haemodialysis should be used to rapidly remove lithium.
MOOD STABILISER
three features of clinical recovery from Lithium Poisoning
- can take days to weeks
- is significantly delayed compared with the decrease in serum lithium concentrations
- Some neurological effects may be permanent.
PSYCHOACTIVE SUBSTANCES
“Cannabinoids”
- THC (Tetra-hydrocannabinol) = agonist
- CBD (Cannabidiol) = antagonist
PSYCHOACTIVE SUBSTANCES
“Cannabinoids” THC
↑ THC = greater “high” effect
PSYCHOACTIVE SUBSTANCES
“Cannabinoids”
↑ CBD = greater analgesic, anti-inflamatory, anti-anxiety effects
BENZODIAZEPINES
Contra-indications
- severe hepatic insufficiency (most are conjugated in the liver)
- alcohol abuse (if liver disease)
- opioids (due to risk of aggravating respiratory depression)
- old age (use with caution dua to longer action hence it require lower doses)
COPD (due to risk of aggravating respiratory depression)
Do not give diazepam by intramuscular injection as absorption is poor and erratic - Onset of action is not much faster than with VO and there is a greater likelihood of causing severe adverse effects - such as respiratory depression.
If an injection necessary:
- it must not be diluted
- must be given slowly over several minutes (to minimise the risk of respiratory depression or arrest.
BENZODIAZEPINES
safer option in patients with liver dysfunction
Oxazepam and Tamezepam
(Outside The liver)
These drugs do not rely on oxidative metabolism in the liver (which is impaired in liver disease). They do not produce active metabolites, meaning their effects are shorter and more predictable.
NO-BENZODIAZEPINES
Zolpidem and zopiclone
These drugs have SIMILAR sedative properties to the BZs but MINIMAL:
- anxiolytic
- muscle relaxant
- antiepileptic properties
Compared with benzodiazepines, they generally cause less morning sedation and have less disruptive effect on normal sleep patterns.
Sodium Valproate in pregnancy
1st trimester: decrease dose to prevent neural tube defects
2nd semester: continue decreased dosage through to 3rd semester
3rd trimester: increase the dosage to prevent seizures
MAOIs are generally well tolerated, but orthostatic hypotension is a common dose-limiting factor. The patient
must be able to reliably comply with drug use and the strict low-tyramine diet (see Table 8.22), as well as avoid
interacting drugs.
Antiepileptics used in bipolar disorder include sodium valproate, carbamazepine and lamotrigine (see Bipolar
disorder). Sodium valproate and carbamazepine should only be used during pregnancy under exceptional
circumstances because of their risk of teratogenicity. The decision to continue or stop the drug should always
be in consultation with the woman and her partner. Women who discontinue their antiepileptic therapy during
pregnancy should be monitored regularly and closely. Relapse can be managed symptomatically using safer
therapy such as antipsychotics or electroconvulsive therapy. Alternatively women can be changed to lithium
after the period of fetal cardiogenesis, about 50 days postconception.
Sodium valproate has been associated with an up to 10-fold (from 0.2% to 2%) increased risk of spina bifida,
as well as other serious malformations (11% risk in total) and coagulopathies. These effects seem to be doserelated,
with increased risk from sodium valproate doses above 1000 mg daily.
Carbamazepine has also been associated with a significant increased risk of spina bifida in addition to
developmental delay and craniofacial defects. The overall risk of major malformations is approximately 6%.
If a decision is taken to continue these antiepileptics, animal data suggest that the risk of neural tube defects
may be reduced if larger than the standard oral dose of folic acid (5 mg daily instead of 0.5 mg daily) is taken
from at least 1 month before conception and continued until at least 3 months gestation.
Carbamazepine use while
breastfeeding with infant jaundice and
liver dysfunction
Monitoring of infant liver biochemistry
and white cell count is worthwhile if the
woman is taking either sodium valproate
or carbamazepine.
These two antiepileptics as
contraindicated while breastfeeding
Antiepileptics used in bipolar disorder
include sodium valproate, carbamazepine
and lamotrigine.
* Sodium valproate: an increased risk of spina
bifida - malformations and coagulopathies.
* Carbamazepine: increases risk of spina
bifida in addition to developmental delay
and craniofacial defects.
* Use a high oral dose of folic acid from at
least 1 month before conception and
continued until at least 3 months gestation.
* Vitamin K oral taken from 36 weeks of
pregnancy reduces the risk of
coagulopathies in neonates.
