Bipolar and Schizophrenia Flashcards
what is thought to be the MoA of lithium?
complex effects on the generation of intracellular second messengers
why does lithium serum concentration need to be measured after 12hrs of first dosing then at least every 3 months?
it has a narrow therapeutic index
how is lithium excreted and what effects does this have?
it is excreted by glomerular filtration and 80% is reabsorbed in the proximal tubule by the same mechanism as sodium so if the body is depleted of salt and water e.g. by vomiting, diarrhoea, then enhanced reabsorption of Na is accompaned by enhanced lithium reabsorption whcih can produce toxicity
name some side effects of lithium
- Nausea
- diarrhoea
- CNS effects (tremor, giddiness, ataxia, dysarthria, mild cognitive and memory impairment)
- hypothyroidism during long-term treatment
- severe toxicity can cause coma, convulsions, profound hypotension, oliguria
what drugs can lithium interact with adversely?
- diuretics (may reduce lithium excretion by depleting intravascular volume)
- ACE-inhibitors and angiotensin II receptor antagonists and soem NSAIDs can reduce renal excretion of lithium
- increased risk of extra-pyramidal side effects when taken with antipsychotic drugs
what class of drug is carbamazepine and what can it be used in?
anticonvulsant - can be used for bipolar.
however, it has a delayed onset of action so may be given initially with a benzo
how long can it take lithium to reach therapeutic effect?
1 week
what is an alternative to lithium for the acute phase in bipolar?
sodium valproate as its sedative action produces a response in 1-4 days
what is the treatment for severe manic symptoms in bipolar?
lithium/sodium valproate/carbamazepine + antipsychotic drug (atypical one usually preferred)
how is depression in bipolar often treated
quetiapine OR
lithium + antidepressant (antidpressants risk provoking switch to mania)
OR
olanzapine + SSRI fluoxetine or lamotrigine
what is an alternative monotherapy to lithium in bipolar disorder?
Quetiapine
what can be used for refractory episodes of mania and depression which has a more rapid action than drug therapy?
ECT
name 4 conventional antipsychotics
- haloperidol
- chlorpromazine
- flupentixol
- sulpiride
name 5 atypical antipsychotics
- risperidone
- olanzapine
- clozapine
- aripiprazole
- quetiapine
why should kidney function be monitored when someone is on lithium?
because it has severe renal toxicity
what tests should be done before starting antipsychotics and then annually thereafter?
FBC
U&Es
LFTs
fasting blood glucose (measure at 6 months)
what should be measured at baseline then at 3 months then yearly when on antipsychotics?
blood lipids and weight
which antipsychotic is effective in treatment resistance schizophrenia?
clozapine
why does clozapine need close monitoring?
due to risk of agranulocytosis
what is the mechanism of action of antipsychotics?
D2 receptor antagonist mainly but also antagonist actviity at alpha-1 adrenoceptors and histamine H1 receptors.
name some examples of the depot preparations of antipsychotics
flupentixol
decanoate
zuclopenthixol decanoate
what are unwanted effects of conventional antipsychotics?
- extrapyramidal side effects (acute dystonias, akathisia, parkinsonism)
- tadive dyskinesia is a late adverse effect resulting in pointless, involuntary and repetitive movements (e.g. lip smacking) which may not resolve on stopping dose
- drowsiness and cognitive impairment
- galactorrhoea
- increased risk of osteoporosis
- erectile dysfunciton and impaired arousal
- neuroleptic malignant syndrome
- drowsiness
- hypotension
- QT prolongation (and consequent arrhythmias)
- weight gain (think of olanzapine begins with an ‘O’ so makes people round, fat)
- antimuscarinic effects
what would acute dystonia present as?
tongue protrusion, torticollis (wry neck), oculogyric crisis (eyes rolled up into head)
what is akathisia?
restlessness
what is a depot version of atypical antipsychotics
olanzapine embonate
what 2 side effects are unique to clozapine
reduced seizure threshold and agranulocytosis (an acute condition involving severe and dangerous leukopenia - lowered WBC count, most commonly neutrophils
what is the optimal length of treatment for antipsychotics in schizophrenia?
2-5yrs
what group of people should antipsychotics be prescribed to with extra caution?
elderly due to increased mortality and morbidity riso
what monitoring is required for patients on antipsychotics?
- BMI
- Bloods for kidney function and FBC
- ECG
- lipid profile
before starting antipsychotics, what should be recorded as a baseline?
- weight
- waist circumference
- pulse
- BP
- fasting blood glucose, HbA1c, blood lipid profile
- prolactin levels
- assessment of movement disorders
- assessment of nutritional status, diet and level of physical activity
- offer ECG if cardiovascular risk or if an inpatient
