drugs Flashcards
drugs causing QT prolongation
Antipsychotics: Haloperidol, quetiapine, chlorpromazine,olanzapine,amisulpride
TCAs: amitryptiline, nortryptiline, imipramine
Citalopram, ecitalpram, venlafaxine
others
chloroquine, hydroxychloroquine, quinine
macrolides: erythromycin, clarithromycin
which anti-psychotic has the smallest effect on the QT interval?
Aripiprazole
side effects of antipsychotics
1st generation: more likely to be extrapyramidal parkinsonian symptoms including tremor -akathisia (restlessness) -tardive dyskinesia -dystonia and dyskinesia -postural hypotension
2nd generation:
more likely to cause blood lipids increased and glucose tolerance decreased and weight gain
also antimuscarinic symptoms such as hypersalivation
You can treat hypersalivation with hyoscine
constipation (can be fatal and lead to toxic megacolon)
sexual dysfunction and decreased libido (this is a big one which causes non adherence)
caridac side effects including arrythmias and qt prolongation
hyperprolactinaemia , breast enlargement and galactorrhoea
blood dyscrasias
neuroleptic malignant syndrome - MUSCLE RIGIDITY, HYPERTHERMIA, FLUCTUATING CONSCIOUSNESS, PALE, TACHYCARDIA
CLOZAPINE:
hypersalivation, agranulocytosis, seizures, constipation
When would you commence clozapine?
for treatment resistant schizophrenia (i.e. tried two antipsychotics-one of which atypical)
how do you start clozapine treatment?
when do they need to come in for blood tests?
start low = 12.5mg daily and increase very slowly (clozapine can cause low BP and myocarditis hence slow titration)
TESTS
you need bloods once a week for 18weeks
then once a fortnight for 1 year
thereafter once a month
if clozapine is stopped for 48 hours then you need to retitrate it from the beginning
name some first generation anti-psychotics
chlorpromazine
haloperidol
name some second generation anti-psychotics
olanzapine
quetiapine
aripiprazole
which drugs do you need to avoid when taking lithium?
NSAIDs
ACE inhibitors
Diuretics
what are the signs of lithium toxicity?
coarse tremor d+v confusion convulsions dysarthria dizziness ataxia
what are the indications for Lithium?
it is a mood stabiliser and can also be used to augment anti- depressants in treatment resistant depression
what is entacapone
is a COMT inhibitor
stops breakdown and metabolisation of Levodopa
what is ripinirole
a dopamine agonist
dopamine agonists (non ergot)
ripinirole
pramiperole
rotigoline
apomorphine
ergot derived dopamine agonist
bromocriptine
pergolide
cabergolide
rarely used because of fibrotic side effects
mono-oxidase B inhibitors
rasagiline
selegiline
what is the initial treatment for Parkinsons disease
L dopa, MOAB inhibitors, or dopamine agonist
how does Levodopa work>
replenishes striatal dopamine (it is a dopamine pre cursor)
what is commonly combined with Levodopa?
a dopamine decarboxylase inhibitor (benserazide or carbidopa)
- this decreases side effects such as nausea and vomiting and cardiovascular side effects
- this also increases the amount of dopamine available in the brain
what is in co-beneldopa
benserazide and levodopa
what is in co-careldopa (Madopar)
carbidopa and levodopa
other treatment options in Parkinsons disease?
anticholinergics
beta blockers
amantadine (NMDA antagonist)
what do antimuscarinic drugs do in parkinsons disease
reduce tremor and rigidity
have little effect on bradykinesia
may be useful in reducing sialorrhoea (hypersalivation)
examples of antimuscarinic drugs
procyclidine hydrochloride
orpheadrine hydrochloride
trihexyphenidyl hydrochloride
common side effect of levodopa- requires counselling
postural hypotension
