Most medications used for schizophrenia are in the phenothiazine family. The atypical antipsychotics are so called because they are chemically quite different. They appear to cause fewer side effects than the phenothiazine drugs

Medications in this family include:

  • Olanzapine (Zyprexa)
  • Risperidone (Risperdal)
  • Clozapine (Clozaril)
  • Quetiapine (Seroquel)
  • Ziprasidone (Geodon)
  • Aripiprazole (Abilify)

Possible Harmful Interaction

The herb St. John’s wort might reduce levels of these medications in the blood.1 This could lead to an increase in the severity of psychotic symptoms.

Perhaps even more dangerously, if medication levels are adjusted for an individual already taking St. John’s wort, stopping the herb could cause these levels to rise, potentially causing dangerous toxic symptoms.

Possible Benefits and Risks

A few studies suggest that the amino acid glycine may augment the action of phenothiazine antipsychotic drugs. It might also augment the action of olanzapine and risperidone, but whether it augments or decreases the effectiveness of clozapine remains unclear.3-7 See the Glycine article for a more detailed discussion of this subject.

Possible Helpful Interaction

Highly preliminary evidence suggests that ginkgo might reduce the side effects and increase the efficacy of various antipsychotic medications, including atypical antipsychotic drugs.2