Psychological Flashcards
What are the treatment options for patients with generalised anxiety disorder?
Sertraline = first-line (SSRI) Alternative = serotonin norepinephrine reuptake inhibitor
What are the treatment options for patients with acute anxiety disorder?
Benzodiazepines - avoid prolonged use
Propranolol
What is the mechanism of action for benzodiazepines?
Propagator of GABA neurotransmission; binds to GABA-A receptors, increases affinity of GABA to its receptor which then increases GABA-A’s opening frequency
How should you prescribe benzodiazepines?
Avoid where possible
Maximum 2-4 weeks use
Anxiety must be severe, disabling or causing the patient unacceptable distress
How should you prescribe SSRIs?
Therapeutic doses are approx the same for anxiety as what you’d prescribe for depression.
Time to onset varies by patient but usually it’s 4 weeks - continue initial therapeutic dose for 4-6 weeks and INCREASE DOSE if no response is shown (don’t switch meds)
What are the side effects of SSRIs?
- Sexual dysfunction
- GI abnormalities (nausea & diarrhoea)
- Insomnia
- Anorexia with weight loss
- Withdrawal on discontinuation
- Serotonin syndrome (tachycardia, agitiation)
What are the features of SSRI toxicity?
Onset: days - week after new SSRI/ increase in current SSRI dose
- Autonomic instability
- Mental status change
- Inducible muscle clonus (via excessive 5-HT1A and 5-HT2A stimulation)
- Hyperreflexia
- Muscle rigidity
- Hyperthermia
Why are SSRIs preferred over TCAs and MAOIs?
SSRIs are significantly less toxic (MAOIs caused most cases historically)
Which SSRIs are most likely to cause serotonin syndrome?
Sertraline
Paroxetine
Fluvoxamine
What pharmacological agents are available for sedation?
Benzodiazepines:
Diazepam (preferred)
Lorazepam
Chlordiazepoxide
What medications can be given as tranquillisers for patients?
Haloperidol
Olanzapine
Lorazepam
How do you manage a benzodiazepine overdose?
Supportive care (ABCDE) Continue management via IV thiamine (Pabrines)
What features would you expect to see in benzodiazepine dependence syndrome?
Tremor Anxiety Perceptual disturbances Dysphoria Psychosis Seizures
How would you manage benzodiazepine withdrawal?
- Benzodiazepine with a prolonged clinical effect (Diazepam = first-line)
- Titrate to effect
- Once symptoms are controlled, gradually taper down dose over several months
N.B. It’s almost impossible to get patients off benzos successfully
Why is lithium used as a mood stabilising drug?
Suspected to be linked to sodium transporters, reduction in suicide risk
What are lithium’s contraindications?
- Significant renal impairment
- Sodium depletion
- Dehydration
- Significant cardiovascular disease
What are the side effects associated with lithium?
- Nausea and diarrhoea
- CNS effects: tremor, ataxis, dysarthria, mild cognitive impairment
- Hypothyroidism
- Diabetes insipidus
- Overdose from its narrow therapeutic window
What are examples of SNRIs?
Duloxetine
Venlafaxine
What is reboxetine’s mechanism of action?
Selective noradrenaline reuptake inhibitor
What are examples of tricyclic antidepressants?
Amitriptyline
Imipramine
Lofepramine
What is mirtazapine’s mechanism of action?
Presynaptic alpha2-adrenoreceptor blocker
What are examples of classic monoamine oxidase inhibitors?
Phenelzine
Tranylcypromine
What is agomelatine’s mechanism of action?
Melatonin receptor agonist and serotonin receptor antagonist
How should a patient be monitored prior to starting antipsychotic medication?
- Weight
- Waist circumference
- Pulse & blood pressure
- ECG if cardiovascular risk factors are identified
- Fasting blood glucose/ HbA1c/ blood lipid profile & prolactin levels
- Assessment of any movement disorders
- Assessment of nutritional status, diet & level of physical activity
Why are antipsychotics contraindicated in dementia patients?
Significantly decreased life expectancy by 7 years; increased risk of strokes
What is meant by ‘anticholinergic life burden’?
Increased risk of dementia, reduced life expectancy, falls, acute confusional states and delirium
What are the non-pharmacological choices for managing a patient with psychosis
- Education
- Family/ caregiver support
What is an adverse drug reaction?
Adverse effects of a drug at its therapeutic doses (NOT therapeutic failure, overdose, drug abuse, non-compliance or medication errors)
What is an adverse drug event?
Occurrence of event after drug exposure; not necessarily caused by the drug
What is the difference between type A and type B adverse drug reactions?
Type A - Augmented = exaggerated response to pharmacological action
High incidence, low mortality
Type B - Bizarre
Give examples of non-selective NSAIDs
Diclofenac Aspirin Ibuprofen Naproxen Indomethacin
Besides ulcers, what are the mild and severe side effects of NSAIDs?
Mild: Heartburn and dyspepsia
Severe: Ulcers, bleeding and perforation
What are common adverse effects of cytotoxic drugs?
Nausea and vomiting
Hyperuricaemia
Neutropenia
What are risks of taking naproxen with ramipril?
Drug related AKI from NSAID with additional affected renal function from ramipril
What drugs is cytochrome P450 (CYP3A4) responsible for metabolising?
- Calcium channel blockers
- Benzodiazepines
- HIV protease inhibitors
- HMG-CoA-reductase inhibitors (statins)
- Warfarin
- Ciclosporin
- Non-sedating antihistamines
What are inhibitors of cytochrome P450?
- Fluconazole
- Clarithromycin
- Erythromycin
- Grapefruit juice
- Ritonavir
What are inducers of cytochrome P450?
- Carbemazepine
- Rifampicin
- Rifabutin
- St. John’s wort
How long to inducers take to act on cytochrome P450?
Days to weeks
How long to inhibitors take to act on cytochrome P450?
Rapidly, within days
What are common examples of enzyme induction?
Combined oral contraceptive + rifampicin
Warfarin + carbamazepine
What are common examples of enzyme inhibition?
Statins + clarithromycin
Warfarin + amiodarone
What are common drug-food interactions?
Tetracycline and milk products
Warfarin + vitamin K containing foods
Grapefruit juice + most drugs
Cranberry juice + most drugs
How is codeine metabolised?
Prodrug that’s demethylated to morphine by CYP2D6
What are the consequences of being a CYP2D6 ultra-rapid metaboliser?
The enzyme will increase the bioavailability of the metabolised drug and increase the patient’s risk of overdose
More side effects and a shorter than expected duration of pain control
What does 3N mean in the context of a diplotype genotype?
There are three alleles present rather than two. This means that there will be an additional copy of one of the genes.
What are the consequences of being a CYP2D6 poor metaboliser?
Patients may not see any effect of codeine/ it takes a really long time to manifest
What scenarios could happen as a result of codeine/CYP2D6 problems?
Breastfeeding in a mother who is an ultra metaboliser
How would one prevent codeine overdose?
- Don’t take codeine first (take standard dose of morphine)
- Don’t take oxycodone, hydrocodone or tramadol as they’re all prodrugs and therefor use CYP2D6
Why is pancytopenia a possible side effect of mesalazine?
Azathioprine induced marrow suppression
How is bone marrow toxicity possible at low azathioprine doses?
Thiopurine methyltransferase (TMPT) is the drug needed to break down 6-MP (active drug) into breakdown products but it could be mutated and have low activity resulting in 6-MP build-up.
What is the difference between pharmacogenetics and pharmacogenomics?
Pharmacogenetics - single drug-gene interactions
Pharmacogenomics - effect of multiple genes on drug response (genome wide association)
