Pharmacology Flashcards
Which is the only antidepressant recommended in <18y? why?
Fluoxetine
Because of increase in suicidal thoughts in the others
What are 4 classes of antidepressants?
SSRIs
SNRIs
MAOIs
TCAs
Which of the following is not an SSRI:
citalopram, duloxetine, sertraline, paroxetine
duloxetine is an SNRI
What does SNRI stand for
serotonin and noradrenaline reuptake inhibitor
SEs SSRI
GI bleed, sexual dysfunction, hyponatraemia, increase in suicidal ideation, QT prolongation
Any drug that increases the availability of serotonin can cause____?
serotonin syndrome
Symptoms of serotonin syndrome
confusion
delirium
shivering
sweating
BP changes
myoclonus
In which situations is serotonin syndrome likely to occur?
When initiating an antidepressant, increasing the dose, overdose, adding another AD or switching AD without allowing ‘washout period’ of the last one
How can you reduce the risk of GI bleed in SSRI
if elderly taking NSAID/aspirin give PPI
Which two SSRIs would be good for patients on a lot of medication?
Citalopram and sertraline have fewest interactions
How should a patient starting an antidepressant be monitored?
Review every 1-2w at the start (1w if <30 or suicide risk). Wait at least 4w before deciding it isn’t working. If partial response, keep waiting for another 2-4 more weeks. See them every 2-4w in the first 3m.
If <30 or suicide risk- see frequently until the risk is no longer clinically significant.
Name two SNRIs
venlafaxine, duloxetine
Which SNRI has different side effects to SSRIs?
Venlafaxine
What extra SEs does venlafaxine have?
BP changes, cardiotoxic in overdose
How long should you remain on an antidepressant for?
about 6m after symptom resolution
How are antidepressants metabolised
hepatic
Can any antidepressants cause withdrawal symptoms?
Yes
How should you come off antidepressants?
Taper over 2-4w
What is the action of Mirtazapine?
Blocks presynaptic alpha 2 receptors which normally inhibit neurotransmitters via negative feedback. This increases monoamine output
Side effects of mirtazipine
Dry mouth, drowsiness, wt gain
Dothiepin, imipramine and lofepramine are what type of antidepressant?
TCA
What type of antidepressant has the highest risk of overdose?
TCAs except lofepramine
Mechanism of TCAs
Block monoamine reuptake (each to different extents)
SEs TCAs
Anticholinergic, antiadrenergic, cardiac arrhythmias, seizures
hypotension, tachycardia, QTc prolongation
Which TCA has fewer side effects
Lofepramine, but rarely it causes hepatic toxicity
TCAs can be split into what two groups?
Sedating and non-sedating
Name some sedating TCA
amitriptyline, clomipramine, dosulepin, doxepin, mianserin, trazodone, trimipramine
Name some less sedating TCAs
Imipramine, lofepramine, nortriptyline.
Mechanism of MAOIs?
Inhibit breakdown of serotonin, and, to a lesser extent, noradrenaline.
Name two MAOIs
phenelzine, tranylcypromine
SEs MAOIs
Anticholinergic, antiadrenergic, tyramine reaction
Hypertensive crisis
What is a tyramine reaction (SE of MAOI)
HTN and throbbing headache if eat food with lots of tyramine- cheese and red wine. Occasionally fatal.
Treatment with _______ is associated with a higher risk of withdrawal effects compared with other antidepressants
Venlafaxine
What is the antidepressant general progression of treatment?
- SSRI
- Up dose
- Switch to different SSRI or alternate antidepressant
- Augment with antipsychotic/lithium etc
- Combination therapy: Venlafaxine & Mirtazapine, or Olanzapine & Fluoxetine
Antipsychotics are split into which two categories?
Typical and atypical
Are typical or atypical antipsychotics first line?
Atypical
Benefit of atypical antipsychotics?
Fewer SEs and may be slightly better at treating negative Sx schizophrenia
Which is the most effective antipsychotic? But what are its negatives?
Clozapine
Significant SEs- agranulocytosis- requires regular monitoring (weekly for 18w, then fortnightly for 1y then monthly).
When do you prescribe clozapine?
when two antipsychotics have failed
Mechanism of action antipsychotics?
Reduce dopamine transmission (D2/D3)
Atypicals- antagonise 5HT2a receptors
Typicals- anticholingergic, antiadrenergic and antihistaminergic.
Unknown why these treat psychosis
May involve ventral striatum
antipsychotics route?
Normally oral, can be IM short acting, occasionally IV.
Some (flupenthixol, fluphenazine and risperidone) can be depot injections every 1-4w which improves adherence.
Would you use antipsychotics for behavioural disturbance in elderly?
No, risk stroke and reduce glycaemic control. Only one you’d use is risperidone short term.
Indications for antipsychotics?
Schizo
Mania
Psycotic depression
Violent/agitated behaviour (haloperidol usually)
Tourette’s in lower doses
SEs typical antipsychotics
Antidopaminergic:
Movement: parkinsonism, akathisia, tardive dyskinesia, acute dystonic reactions (torticollis, increased tone, oculogyric crisis)
AND
Hyperprolactinaemia: galactorrhoea, breast cancer, amenorrhoea, sexual dysfunction
What is an oculogyric crisis?
Keep looking up involuntarily
What types of typical antipsychotics have slightly different SEs?
Phenothiazines- blood dyscrasias, retinal pigmentation, photosensitivity, cholestatic jaundice
What are the SEs of atypical antipsychotics?
Metabolic- wt gain, T2DM, dyslipidaemia
Which atypical antipsychotic has different profile of SEs?
Clozapine:
Nocturnal enuresis, constipation, salivation, BP changes, fever, nausea, seizures, agranulocytosis
What are the side effects of all antipsychotics?
C-CHANS
Cardiac (QT prolongation, arrhyth, 2x risk sudden cardiac death)
Anti-Cholinergic (dry mouth, urinary retention, constipation, confusion)
Anti-Histaminergic (sedation)
Anti-Adrenergic (postural hypotension)
Neuroleptic malignant syndrome
Change Seizure threshold
What is neuroleptic malignant syndrome?
Increased serum CK, hyperpyrexia, increased muscle tone, confusion, autonomic instability
How long should antipsychotics be continued?
1-2y after first episode, but 98% relapse after 2y so often continue for 5y. Many are non-adherent anyway
What advice should you give to patients if they decide to stop their antipsychotic?
Taper it over at least 3w as stopping suddenly doubles the risk of relapse
What monitoring should be done when starting antipsychotics? And how frequently after starting?
Prior and yearly:
- ECG
- BMI and waist circ
- Bloods: FBC, U&E, lipid profile, HbA1c, glucose, LFTs, prolactin
Why can’t clozapine and carbemazepine be used together?
Both risk agranulocytosis
What is the risk with antipsychotics and metaclopramide?
Extra pyramidal SEs
Risk with (IV) erythromycin & quetiapine?
QT prolongation
What is the main mood stabiliser?
Lithium
Indications for lithium?
Prophylaxis in recurrent uni/bipolar affective disorder
Acutely in mania
Augmentation of ADs in resistant depression
Schizoaffective illness
Control aggression
Mechanism of lithium
Unclear
Interacts with all body systems that involve sodium, potassium, calcium and magnesium
probably affects neurotransmitters (serotonin, dopamine, noradrenaline, acetylcholine)
Interferes with cAMP linked receptors- action on kidney and thyroid
Route of lithium
Oral
Excretion of lithium
Renal
Contraindications for lithium
Thyroid disease
Renal disease
Cardiac disease
Addison’s disease
Monitoring required for lithium?
Prior and 6 monthly: TFTs, eGFR and weight
Serum lithium- weekly at first and then 12 weekly
When should serum lithium be monitored in relation to dose?
12h after last dose
SEs of lithium at the therapeutic dose
Nausea
fine tremor
wt gain
oedema
polydipsia and polyuria
worse psoriasis and acne
Hypothyroid
What is the therapeutic dose of lithium?
0.4-1mmol/L (serum)
Symptoms of lithium toxicity
D&V
coarse tremor
slurred speech
ataxia
drowsy and confused
convulsions and coma
What is the treatment for lithium toxicity?
Stop the lithium and fluids
What could precipitate lithium toxicity?
Dehydration and diuretics
What does lithium interact with?
NSAIDs
Calcium Channel Bs
some abx
What are 3 other mood stabilisers?
Sodium valproate
Carbemazepine
Lamotrigine
What is lamotrigine especially good at as a mood stabiliser?
Preventing depressive episodes
SEs sodium valproate?
GI, weight gain, hair loss with curly regrowth, dose related tremor, thrombocytopenia
SEs lamotrigine
skin incl SJS
aseptic meningitis
dizziness
diplopia
leucopenia
insomnia
nausesa
Which mood stabilisers should be avoided in pregnancy?
Lithium
Lamotrigine
Valproate
Are different brands of lithium bioequivalent?
No, should know which brand they are on
Does lithium need to be tapered to stop?
Yes
SSRI + lithium could lead to what?
Mania
What type of diuretic should be used with lithium?
Loop
What can NSAIDs do to lithium levels in blood?
Increase
Mechanism Valproate?
GABA
What is a caution in carbemazepine?
Hepatic enzyme inducer
SEs carbemazepine?
agranulocytosis, hyponatraemia.
Nitrazepam Flurazepam Diazepam Alprazolam Clobazam Chlordiazepoxide
These are short or long acting benzos?
Long
Lorazepam
Loprazolam
Lormetazepam
Temazepam
Short or long acting benzos?
Short
What do benzos do?
anxiolytic
sleep inducing
anticonvulsant
muscle relaxant
Indications of benzos?
Insomnia
GAD (short term and not for phobias or panic disorders)
Alcohol withdrawal
Control violent behaviour
2nd line for refractory epilepsy
Route of benzos?
Usually oral
Sometimes IM, IV, rectal
What is it important to consider when giving benzos?
Exclude underlying conditions and consider behavioural alternative treatment
Mechanism of benzos
Potentiate the inhibitory effects of GABA (Decreases neuronal excitability)
What are some other anxiolytics other than benzos?
Zopiclone and related
Antihistamines
Buspirone
SEs benzodiazepines?
Drowsy
Ataxia (falls risk)
Amnesia
Dependence
Disinhibition (may lead to aggression)
Potentiates alcohol and other sedatives- may be a dangerous combo
Signs of benzo OD?
Resp depression
Drowsy
Dysarthria
Ataxia
Treatment for benzo OD
Flumazenil
but caution in mixed OD or benzo-dependent pts
What is a risk with anything but short term benzo?
Tolerance
Withdrawal Sx benzos?
Anxiety
Shakiness
Abdo cramps
Perceptual disturbances
Persecutory delusions
Seizures
Why might you get increased dreaming when stopping benzos?
They inhibit REM sleep
How long can weaning off iatrogenic benzo dependence take?
months- years
What does zopiclone do?
Hypnotic but without the anti-convulsant or muscle relaxing properties
Can zopiclone cause dependency?
Yes
What is Buspirone? Including mechanism.
Anxiolytic used short term for anxiety. 5HT1a partial agonsit
What are the two dementia drugs?
Acetylcholinesterase inhibitors
Memantine
Name the three AChE inhibitors
Donepezil
Rivastigmine
Galantamine
First line for mild-mod alzheimers?
Any AChEi
First line for mild-mod Lewy body? What if this isn’t tolerated?
Donezepil or Rivastigmine first line, if not then galantamine
Severe lewy body treatment?
donezepil or rivastigmine, if not tolerated then memantine
Should you give AChEi or memantine in fronto temporal dementia?
No
Donezepil mechanism
Reversible inhibitor of AChE
Donezepil cautions in?
asthma/copd
some cardiac
peptic ulcer
Donezepil SEs
Mood/behavioural changes
muscle cramps
hallucinations
syncope
Urinary incontinence
Appetite decrease
sleep probs
AChEi doses should start ____
low and increase
Galantamine mechanism?
Reversible inhibitor of AChE with some nicotinic receptor agonist properties
Galantamine is available in which two forms?
Modified and immediate release
Galantamine cautions?
GI obstruciton or surgery
Urinary outflow obstructin or bladder surgery
Some HD
COPD/severe asthma
seizures
SEs galantamine
Skin reactions- SJS
decreased appetite
arrhyth
Mood changes
hallucinations
HTN
muscle spasms
Tremor
Galantamine and renal disease?
Avoid if eGFR <9mL/min
Rivastigmine mechanism
Reversible non-competitive inhibitor of AChE
Rivastigmine routes available
PO or transdermal
Rivastigmine cautions
GI ulcers
Bladder outflow obstruction
Hx asthma/copd
Sick sinus synd
Seizures
What is the risk with transdermal rivastigmine?
Leave the old patches on and have fatal OD
SEs rivastigmine
Appetite decrease
Mood changes
Hyperhidrosis
Hypersalivation
HTN
Movement disorders
Skin reactions
Urinary incontinence
PO: hallucinations, parkinsonism, sleep disorder, gait change
TD: gastric ulcer
What should you monitor when the pt is on rivastigmine
body weight
Instructions for transdermal administration of rivastigmine
Clean, dry, non-hairy, non-irritated skin on back, upper arm or chest. Remove after 24h. Avoid same site for 14 days.
Which AChEi for dementia in a patient who needs modified release?
Galantamine
Which AChEi for dementia in a patient who can’t tolerate oral medication?
Rivastigmine transdermal
Which AChEi for dementia in a patient with history of bladder outflow obstruction?
Donezepil
Memantine action (and how does this help dementia)
Glutamate receptor antagonist. Glutamate is the major excitatory neurotransmitter in CNS. Inhibiting its action prevents cell damage.
What is a glutamate receptor antagonist also known as?
NMDA receptor antagonist
Memantine caution?
Epilepsy and avoid if eGFR <5mL/min
SEs memantine
dizziness
headaches
constipation
confusion
worse balance
St Johns wort is a complementary medicine used in what?
Depression (mild-mod)
Anxiety
SAD
Sleep disorders
Is there evidence for St Johns wort in severe depression
No
What is the problem with St John’s wort (2)
Interactions
May trigger mania in bipolar
What is given for parkinsonian SEs of APs?
Procyclidine (or other antimuscarinics)
Can you give procyclidine in tardive dyskinesia?
No it worsens it
What does tardive dyskinesia look like?
TD causes stiff, jerky movements of your face and body that you can’t control. You might blink your eyes, stick out your tongue, or wave your arms without meaning to do so.
Smacking lips
Flapping arms
Blinking
What is akathisia?
Feeling of inner restlessness. V unpleasant.
Tardive dyskinesia treatment
Worrying as may be irreversible on withdrawing therapy and treatment is usually ineffective. Treat ASAP
Swap or stop the AP
Akathisia treatment
Benzos, propanolol
Neurotransmitter in depression, anxiety, ADHD, migraine, OCD
Serotonin
Neurotransmitter in alzheimers
Acetylcholine
Neurotransmitter in Schiz and parkinsons
Dopamine (increased in schiz and decreased in park)
Neurotransmitter in Epileptic seizures and alcohol withdr
GABA
GABA is brain on or off?
Off
What neurotransmitter is brain ‘on’
Glutamate
Neurotransmitter in depression decreased (not serotonin)
Noradrenaline
Neurotransmitter in migraine, stroke, autism
Glutamate
What is the action of monoamine neurotransmitters on the nervous system?
–> second messengers–> increased transcription factors –> increased BDNF –> increase neuroplasticity and neurogenesis in hippocampus
What decreases rate of transcription factors (and hence BDNF and neuroplasticity and genesis)?
Cortisol
Neurotransmitter in caffeine
Adenosine
Neurotransmitter in hunger
Cholecystokinin
Neurotransmitter in pain and appetite regulation, co-ordination and learning
Endocannabinoids
Neurotransmitters in tobacco
Acetylcholine and dopamine