Atypical antipsychotics

Atypical antipsychotics

Atypical antipsychotic drugs are agents designed to treat schizo-phrenia. They include aripiprazole, clozapine, olanzapine, paliperi-done, quetiapine, risperidone, and ziprasidone.

Pharmacokinetics

Atypical antipsychotics are absorbed after oral administration.

Metabolism and excretion

Atypical antipsychotics are metabolized by the liver. Metabolites of clozapine, olanzapine, quetiapine, and ziprasidone are inactive, whereas risperidone and paliperidone have active metabolites.

They’re highly plasma protein-bound and eliminated in urine, with a small portion eliminated in stool.

Pharmacodynamics

Atypical antipsychotics typically block the dopamine receptors, but to a lesser extent than the typical antipsychotics, resulting in far fewer extrapyramidal adverse effects. Additionally, atypical an-tipsychotics block serotonin receptor activity.

Putting it together

These combined actions account for their effectiveness against the positive and negative symptoms of schizophrenia with mini-mal extrapyramidal effects.

Pharmacotherapeutics

Atypical antipsychotics are considered the first line of treatment for patients with schizophrenia because of equal or improved ef-fectiveness combined with improved tolerability.

Lower doses do for dementia

Atypical antipsychotics are commonly used to treat behavioral and psychotic symptoms in patients with dementia. Dosages are significantly lower for these patients than for patients with schizo-phrenia.

Drug interactions

Drugs that alter the P-450 enzyme system alter the metabolism of some atypical antipsychotics.

The straight “dopa”

Atypical antipsychotics counteract the effects of levodopa and other dopamine agonists. (See Adverse reactions to atypical an-tipsychotics.)