Do patients receive a full dose of olanzapine (atypical antipsychotic) with orally disintegrating tablets (ODTs) compared to regular tablets?

Bioequivalence of Olanzapine Formulations

Patients receive the full dose with both regular tablets and orally disintegrating tablets (ODTs) of olanzapine—these formulations are bioequivalent and deliver identical systemic drug exposure. 1

Evidence for Bioequivalence

• Pharmacokinetic studies definitively demonstrate that ZYPREXA tablets and ZYPREXA ZYDIS (olanzapine orally disintegrating tablets) are bioequivalent formulations. 1
• Both formulations achieve the same area under the curve (AUC) and maximum plasma concentrations, meaning the total amount of drug absorbed into the bloodstream is identical regardless of which formulation is used. 1
• The FDA-approved labeling explicitly states this bioequivalence, confirming that switching between formulations does not require dose adjustment. 1

Pharmacokinetic Profile

• Olanzapine reaches peak plasma concentrations approximately 6 hours after oral administration with either formulation. 1
• The drug undergoes extensive first-pass metabolism, with approximately 40% metabolized before reaching systemic circulation—this occurs equally with both tablet types. 1
• Food does not affect the rate or extent of olanzapine absorption for either formulation. 1

Clinical Implications

• The primary advantage of ODTs is improved medication adherence and ease of administration, not increased drug delivery. 2
• ODTs begin disintegrating in the mouth within seconds and can be swallowed with or without liquid, which facilitates administration in patients who have difficulty swallowing or who may attempt to "cheek" medications. 1, 2
• The orally disintegrating formulation is particularly useful in psychiatric disorders requiring long-term treatment where adherence is challenging, but it delivers the exact same systemic dose as regular tablets. 2

Common Pitfall to Avoid

• Do not increase the dose when switching from regular tablets to ODTs or vice versa—this is a critical error that could lead to overdosing, as the formulations are bioequivalent and require identical dosing. 1
• The perception that ODTs might deliver less drug because they dissolve quickly is incorrect; the dissolution in the mouth does not affect systemic absorption, which occurs in the gastrointestinal tract after swallowing. 1