Antipsychotic Drugs

Question 1

Antipsychotic Drugs

Traditional

Answer 1

major tranquilizers and neuroleptics

Traditional (conventional) Antipsychotic Drugs =

phenothiazine, thioxanthene, butyrophenone

USE: alleviating psychotic symptoms and used most often with Schizophrenia. as well as mania, delusions, hallucinations w/major depressive dx, and organic psychoses.

Effective for positive symptoms like hallucinations, delusions, agitation but NOT for negative symptoms.

Mode of Action: blocking dopamine receptors in the brain. Dopamine hypothesis: overactivity at dopamine receptors result in oversensitiveity or excessive dopamine levels for Schizophrenics. link proven that increased dopamine levels produces symptoms of schizophrenia.

Side Effects: anticholinergic and extrapyramidal effects, neuroleptic malignant syndrome.

1. Anticholinergic effects: dry mouth, blurred vision, urinary retention, constipation, tachycardia, delayed ejaculation.
   
   1. appear early and tolerance develops w/in a few weeks/months.
2. Extrapyramidal effects: caudate nucleus dopamine receptors effected.
   
   1. Parkinsonism, akathisia (motor restlessness), acute dystonia (muscle spasms in the mouth, face, and neck) are most common.
3. Tardive Dyskinesia = serious extrapryramidal effect. more common in females and older patients and is late occurring.
   
   1. symptoms similar to Huntington’s, infoluntary rhythmic movements of jaw, lips, tongue, and extremities.
   2. mostly irreversible, but improved with discontinuation of drug and GABA agonist or other benzodiazepine.
   3. Haloperidol is the most potent and has teh most severe extrapyramidal effects.

Neuroleptic Malignant Syndrome (NMS): rare but fatal side effect characterized by rapid onset of motor, mental and autonomic symptoms of muscle rigidity, tachycardia, hyperthermia, and altered consciousness.

Stop drug immediately.

Question 2

Atypical (Novel) Antipsychotic Drugs

Answer 2

USE: treat Schizophrenia and other disorders with psychotic symtoms.

Clozapine is especially effective for Bipolar Dx.

Alleviate both positve and negative symptoms.

But have a slower onset of therapeutic effects

MODE OF ACTION: act on D4/dopamine receptors as well as receptors for other neurotransmitters including serotonin and glutamate.

Side Effects: anticholinergic effects, lowered seizure threshold and sedation.

Extrapyramidal side effects are much less common (except for akathisia) especially for tardive dyskinesia.

but can produce agranulocytosis (decrease in white blood cell type), and other blood dyscrasias; thus, close blood monitoring.

may also cause neuroleptic malignant syndrome.