Antipsychotic Drugs: Types, Uses and Side Effects

Antipsychotic drugs are the medications which are used to treat psychosis which is a condition in which the patient is suffering from the mental illness and there has been loss of contact with reality. The patient is not able to recognize what is real and what is not because patients thoughts and perceptions are disrupted. It is one of the most frightening situation for the patient and its relatives therefore antipsychotic drugs have become an integral part of the psychiatric medications. Proper diagnosis of the psychosis should be done before prescribing the antipsychotic drugs because there are certain conditions like high fever, infections etc can also cause psychosis in the patient.

Antipsychotic Drugs Types

• Typical (first generation antipsychotics)
  • Potent: Haloperidol, Fluphenazine
  • Non-Potent: Thioridazine, Chlorpromazine
• Atypical (second generation antipsychotics):
  • Aripiprazole
  • Asenapine
  • Clozapine
  • Olanzapine
  • Quetiapine
  • Risperidone
  • Ziprasidone
  • Iloperidone

Also Read: Delayed Sleep Phase: Causes, Symptoms, Risk Factors, Diagnosis and Treatment

Mechanism Of Action

• Blocks dopamine D2 receptors by increasing cAMP, thus It antagonizes the  mesolimbic System.
• Atypical antipsychotics also block Serotonin 5-HT2 Receptors. Aripiprazole Is a D2 receptor partial agonist.

Also Read: Pseudobulbar Affect Disorder: Causes, Symptoms, Diagnosis, Treatment and Complications

Clinical Use

• Schizophrenia- Typical antipsychotics primarily treat positive symptoms.
• Atypical antipsychotics treat both positive and negative symptoms.
  • Disorder with concomitant psychosis example bipolar disease
  • Tourette syndrome
  • OCD
  • Huntington's disease
  • Clozapine Is used for treatment, resistant psychotic disorders, or those with persistent suicidality.

Also Read: Reactive Attachment Disorder: Causes, Symptoms, Risk Factors, Diagnosis, Treatment and Complications

Adverse Effect

• Antihistamine action – sedation
• Alpha-one adrenergic action – Orthostatic hypertension
• Antimuscarinic action– dry mouth, constipation, used with caution in dementia
• Metabolic side effects – weight gain, hyperglycemia, lipidemia.(Require regular BMI, fasting glucose and lipids, blood pressure, waist circumference)
• The metabolic side effects are more with Clozapine and Olanzapine
• Endocrine side effects due to tuberoinfundibular pathway– hyperprolactinemia Leading to galactorrhea, oligomenorrhea, gynecomastia.
• Cardiac- QT- prolongation
• Neurological -Neuroleptic malignant syndrome
• Ophthalmologic
• Chlorpromazine- corneal deposits
• Thioridazine-retinal deposits
• Clozapine- Agranulocytosis (there is a need to monitor WBCs closely) seizures, and myocarditis.
• Olanzapine- Weight and diabetes mellitus.

Also Read: Borderline Personality Disorder: Causes, Symptoms, Risk Factors, Diagnosis, Treatment, Prevention and Complications

Extra pyramidal Side Effects

The following adverse effects can occur in hours to days:

Acute Dystonia– muscle Spasm, stiffness, Oculogyric crisis. The Treatment is done by Discontinuation of agent and Benztropine, Diphenhydramine are prescribed. Airway protection should be considered.

Days to Months

1. Akathisia (restlessness) Treatment – Reduce the antipsychotic dose. Beta blockers, Benztropine, Benzodiazepine can be given to reduce these adverse effects.
2. Parkinsonism (bradykinesia) Treatment- Reducing the dose, Switching to another antipsychotic with less potential to cause EPS. The drugs like Benztropine, Amantadine can be administered.

Months to years- Tardive Dyskinesia 

1. Chorea mainly orofacial – Rhythmic movement of face, lips and tongue
2. Choreo athetoid movements of trunk and extremities.
3. After prolonged use of antipsychotic more than six months and older women.
4. Cannot be reversed, gets worse with treatment line screen for it and stop the medication once it starts.

Also Read: Narcissistic Personality Disorder: Causes, Symptoms, Diagnosis, Treatment, Prevention and Complications

Treatment

Valbenazine: VMAT-2 inhibitor, Benzodiazepines, botulinum toxin injection, deutetrabenazine.

• Typical antipsychotics have greater affinity for D2 receptors than a typical psychotics, which causes risk for hyperprolactinemia, extrapyramidal side effects, Neuroleptic malignant syndrome.
• High potency Typical antipsychotics have more neurological side effects. Example extrapyramidal side effects.
• Low potency antipsychotic have more antihistamine, anti-alpha one Adrenergic And Antimuscarinic effects.

Also Read: Antisocial Personality Disorder : Causes, Symptoms, Risk Factors, Diagnosis, Treatment, Prevention and Complications

Choice of Drugs

• Normal patients are given atypical antipsychotics.
• Noncompliant patients:
  • Agitated – IM Risperidone or Ziprasidone or olanzapine or haloperidol
  • Dysphagia- oral dissolving tablets olanzapine or Risperidone
  • Chronic noncompliant – depot olanzapine or risperidone Long acting injectables given intramuscularly every 2 to 4 weeks.
  • Resistant/everything failed – clozapine
  • Duration of treatment with antipsychotics

1. One episode requires two years of treatment.
2. Two episodes require five years of treatment and three episodes require lifelong treatment with antipsychotics.

Also Read: Illness Anxiety Disorder: Causes, Symptoms, Risk Factors, Diagnosis, Treatment, Prevention and Complications