The Clinical Pharmacology of Ziprasidone (Geodon® or Zeldox®) From the
Food and Drug Administration (FDA) Reviewer
Abstract
Ziprasidone (Geodon®), also known at the time of submission to the Food
and Drug Administration (FDA) as Zeldox®. It was submitted initially for
the treatment of psychiatric disorders e.g., Schizophrenia. However,
there was delay on its approval due to increase of QT prolongation,
which was discussed at the FDA Advisory Committee. This review focused
on the clinical pharmacology and the pharmacokinetics (PK) of the drug,
specifically at the time of submission to the FDA and other related
updated references. The sponsor (Pfizer) summitted about 40 clinical
pharmacology and PK studies including QT prolongation studies. There
were four capsules formulation at that time: 20, 40, 60, and 80 mg and
one intramuscular (IM) strength in another New Drug Administration (NDA)
that came subsequent to oral route. The drug has to be given with food
to increase the bioavailability to 60% (two-fold increase). Ziprasidone
is extensively metabolized after oral administration with only a small
amount excreted in the urine (<1%) or feces (<4%)
as unchanged drug. Approximately 20% of the dose is excreted in the
urine, with approximately 66% being eliminated in the feces. Some of
its metabolites are active. Ziprasidone has very high, sub nanomolar
binding affinity for the human serotonin.