Study of the Effects of Pantoprazole on Levels of Prescribed Psychiatric Medications

A Pilot Study to Determine if Pantoprazole Modifies Steady-State Plasma Concentrations of Orally Administered Psychotropic Medications

The purpose of this 9-day study is to determine if:

1. Pantoprazole modifies the steady-state plasma concentrations of orally administered psychotropic medications including valproic acid, lithium, and second-generation antipsychotics (i.e., aripiprazole, asenapine, clozapine, lurasidone, olanzapine, paliperidone, quetiapine, risperidone, ziprasidone)
2. Serum gastrin levels change within a week of starting or stopping pantoprazole

Individuals with psychiatric diagnoses may be predisposed to gastroesophageal reflux disease because of the widespread use of alcohol, cigarettes, and certain psychotropic drugs in this population. Consequently, they are often prescribed proton pump inhibitors. To our knowledge, no studies have been conducted to determine the effects of proton pump inhibitors on plasma levels of psychotropic drugs. The present clinical study will assess the effects of pantoprazole on the pharmacokinetics of valproic acid, lithium, and second-generation antipsychotics.

Inclusion Criteria:

• Participants must be fluent in English
• Participants with a psychiatric diagnosis and currently treated with one or more of the following medications: valproic acid, lithium, or a second-generation antipsychotic (i.e., aripiprazole, asenapine, clozapine, lurasidone, olanzapine, paliperidone, quetiapine, risperidone, or ziprasidone)
• Participants on a stable dose of valproic acid, lithium, and/or a second-generation antipsychotic for a sufficient period of time that ensures they are at steady state
• Participants with symptoms of gastroesophageal reflux disease (GERD) that would benefit from treatment with pantoprazole or participants currently treated for GERD with pantoprazole for more than 8 weeks and are currently symptom free.

Exclusion Criteria:

• Participants that are hypersensitive to pantoprazole
• Pregnant or lactating women
• Women of childbearing age not using reliable contraception
• Any postsurgical complications of the gastrointestinal tract that might impair absorption
• Clinically relevant abnormalities of laboratory parameters
• Participants treated with another acid suppressing agent (e.g., H2 receptor antagonists, antacids, alginates, etc)
• Participants treated with atazanavir, delavirdine, erlotinib, nelfinavir, and/or posaconazole