pharmacology 2 Flashcards
Antipsychotics
Used to manage psychosis and other illnesses which cause a loss
of contact with reality
(aka neuroleptics – 1st gen.
an leave
the person experiencing these symptoms at risk
• Perceptual disturbances, hallucinations, delusions, thought
disorders and/leading to bizarre or unusual behaviours
most common diagnoses requiring antipsychotic
Schizophrenia, schizo-affective disorder and other psychotic
disorders
• Other conditions may also respond to
antipsychotic medication
bipolar disorder, major depression,
delirium and substance-induced psychosis
Antipsychotic medications are broken into two main groups
Classic/Typical (first generation) and Atypical (second
generation – 1990’s onwards)
Typical Antipsychotics
• Centrally-acting dopamine receptor antagonist
• The higher the affinity with D2 receptors, the more powerful
the drug
• Better at reducing positive symptoms of schizophrenia than
the negative symptoms
• Alter brain structure (increase basal ganglia volume,
decrease cortical volumes)
Major Problem Typical Antipsychotics
• Disrupts other dopaminergic pathways in the brain:
• Extrapyramidal system
• Hypothalamic-pituitary connection regulating hormone
secretion (PROLACTIN levels)
• Extrapyramidal system
that modulates voluntary
movements
Motor disturbances or extrapyramidal side effects (EPSEs)
- Dystonia
- Pseudo-Parkinsonism
- Akathisia
- Tardive dyskinesia (TD, TDK):
Dystonia
involuntary muscle contractions that cause twisting, movement, odd
posture, “look-ups” (oculogyric crisis)
• Pseudo-Parkinsonism:
: slowness and rigidity that can mimic parkinsonism (D2
receptor involvement)
Akathisia:
involuntary movements that can’t be controlled eg marching in place
Tardive dyskinesia (TD, TDK)
facial grimacing, ‘piano fingers’, jaw swinging,
blinking, restlessness
Treating EPSEs
Using antimuscarinic drugs (such as benztropine) and/or reducing or stopping
the antipsychotic medication can be effective in reversing dystonia,
pseudoparkinsonism and akathisia
• Tardive dyskinesia doesn’t usually respond to benztropine or to reducing or
stopping antipsychotics - Prevention is the most effective alternative
(indication, efficacy, dose)
Commonly Prescribed
Antipsychotics
Typicals:
\: • Haldol (haloperidol) • Loxitane (loxapine) • Mellaril (thioridazine) • Moban (molindone) • Navane (thiothixene) • Prolixin (fluphenazine) • Serentil (mesoridazine) • Stelazine (trifluoperazine) • Trilafon (perphenazine) • Thorazine (chlorpromazine)
Atypicals:
• Abilify (aripiprazole) • Clozaril (clozapine) • Geodon (ziprasidone) • Risperdal (risperidone) • Seroquel (quetiapine) • Zyprexa (olanzapine)
Atypical Antipsychotics - Developed as a
response to the adverse
effects of Typicals
Atypical antipsychotics may interact with dopamine receptors, but
also appear to produce effects on other systems
Atypical Antipsychotics are less prone to
Less prone to produce extra-pyramidal side-effects (EPSEs),
particularly motor disturbances
Clozapine
was the first of these Atypicals, developed in 1958 but then withdrawn due to the potentially fatal side-effect of agranulocytosis (neutropenia) – approved for use 30 years later in treatment-resistant schizophrenia
Neuroleptic Malignant Syndrome (NMS)
NMS is a dangerous adverse effect of antipsychotic medications
of any kind Uncommon, but FATAL if diagnosis and intervention are not RAPID!
Typical NMS presentation involves:
Hyperthermia (temp >380C)
• Muscle rigidity (“lead pipe” rigidity)
• PLUS two of the following – diaphoresis, dysphagia,
incontinence, changes in level of consciousness (confusion to
coma), mutism, elevated or labile BP, creatine phosphokinase
(CPK) elevation, tremor or tachycardia
Neuroleptic Malignant Syndrome (NMS)
Obviously, treatment must be given URGENTLY!
Immediately cease the offending antipsychotic!!
• Commence medical care
• Correct dehydration and electrolyte imbalance
• Monitor for and respond to symptoms of cardio-respiratory
and renal failure
• Consider the administration of medications to counter
agitation and other symptoms
Alternative antipsychotic treatment must be considered –
returning to the same/different antipsychotic medication
requires medical supervision
