Antipsychotics

Antipsychotics

Indications

  • Used for the treatment of schizophrenia and other psychotic disorders; selected agents are also used in the treatment of bipolar mania, as antiemetic, in the treatment of intractable hiccoughs, and for control of tics and vocal utterances in Tourette’s disorder.

Typical antipsychotics

  • Block postsynaptic dopamine receptors in the basal ganglia, hypothalamus, limbic system, brainstem, and medulla.
  • Demonstrate varying affinity for cholinergic, alpha-1-adrenergic, and histaminic receptors.
  • Inhibit dopamine-mediated transmission of neural impulses at the synapses.

Atypical antipsychotics

  • Weaker dopamine receptor antagonists than the typical antipsychotics
  • Potent antagonists of the serotonin type 2A (5H T-2A) receptors
  • Exhibit antagonism for cholinergic, histaminic, and adrenergic receptors
  • Contraindicated in hypersensitive, comatose, or severely depressed patients; elderly patients with dementia-related psychosis; certain medications are contraindicated in patients with a history of Q T prolongation or other heart issues.
  • Caution with elderly or debilitated patients; patients with cardiac, hepatic, or renal insufficiency; those with a history of seizures; patients with diabetes or risk factors for diabetes; clients exposed to temperature extremes under conditions that cause hypotension; and pregnant clients or children

Drug interactions

Interacting Drugs

Adverse effects

Antihypertensives, CNS depressants, Epinephrine or dopamine in combination with haloperidol or phenothiazine

Additive and potentially severe hypotension

Oral anticoagulants with phenothiazine

Less effective anticoagulant effects

Drugs that prolong Q T intervals

Additive effects

Drugs that trigger orthostatic hypotension

Additive hypotension

Drugs with anticholinergic effects, prescription and over-the-counter drugs

Additive anticholinergic effects including anticholinergic toxicity, which includes flushing, hypertension, dry mouth, mydriasis, urinary retention, altered mental status, tachycardia, and tremelousness