Schizophrenia drugs and side effects Flashcards
what is an agonist?
a drug that binds to the receptor, producing a similar response to the intended chemical and receptor
what is an antagonist?
a drug that binds to the receptor either on the primary site, or on another site, and all together stops receptor from producing a response
Where is D1 and D2 found?
- found in both limbic striatal reas
- other subtypes - D3,4,5 in smaller no. but more discrete distribution
the ideal antipsychotic
- pure D2 receptor antagonist, only active in mesolimbic pathway
dopaminergic side effects?
extra pyramidal side effects
- acute dystonic reaction - involuntary contractions of muscles of the extremities, face, neck, abdomen pelvis etc - leading to abnormal movement and posturing
- parkinsonism -movement related affects similar to Parkinsons - rigidity, bradykinesia, tremor.
- tardive dyskinesia - grimacing, smacking of the lips, sticking out tongue (wilkie)
neuroleptic malignant syndrome
hyperprolactinaemia
akathesia/restless legs
what can you add in to treat EPSE? in particular Parkinson’s
- procyclidine 5mg - PO/IM
- trihexyphenidyl
- orphenadrine
-> all anti-cholinergic aimed to treat muscle stiffness etc
how else can you treat EPSE?
change antipsychotic, clozapine?
what is neuroleptic malignant syndrome?
- rare but potentially serious idiosyncratic reaction to antipsychotics (usually 1st gen, lower risk in 2nd gen and aripiprazole)
- associated w hypothalamic pathway
- onset over hours 24-72hrs lasts for days untreated
- fatal in up to 20% (oral meds) or 30% (depot) of cases if not treated
how does NMS present?
- increasing muscle tone, pyrexia, changing pulse/BP > BP > rhabdo because of inc muscle tone > ARF (acute renal failure due to build up of proteins) > coma > death
triad of
- increasing muscle tone
- autonomic instabililty
- malignant hyperpyrexia
what is the investigations for NMS?
creatinine kinase
- in there 1000’s…
treatment for NMS?
stop antipsychotic - consider onward mx of their schizophrenia
rapid cooling, renal support i.e. dialysis
skeletal muscle relaxants e.g. dantroline
dopamine agonists e.g. bromocriptine (knock drug off receptors and allow normal functioning to be resumed)
-> emergency situation admit to ICU
prolactin role in dopamine pathway
prolactin release is inhibited by dopamine
blockade of dopamine leads to increased prolactin release
in women:
- galactorrhoea -> decreased libido, arousal, anorgasmia
- amenorrhoea, anovulation
in men:
- gynaecomastia
- ED, oligospermia, decreased libido
in both
- decrease bone mineralisation, bone density > osteoporosis, falls > fractures
BOOBS, BALLS, BITS AND BONES
define akathisia
means ‘to sit’
- affects up to 20% of patients
- manifests days-weeks of treatment
results in pacing, rocking from foot to foot, unable to sit or stand still, poor sleep as a result, inc suicide risk
- B-blocker e.g. propanolol 1st line
- benzodiazepines e.g. clonazepamn 2nd line
name some anti-cholinergic side effects
dry mouth
blurred vision
constipation
memory - cognition
name some 5HT2 (serotonin receptor) side effects?
implicated in weight gain > metabolic syndrome > type 2DM
