Objective: A post-hoc analysis of the data from a randomised clinical trial involving prescription of antipsychotic treatment to never treated first-onset psychotic patients was used to compare the weight change after 6-week olanzapine treatment (standard tablets vs. orally disintegrating formulation).
Method: In the subgroup of 38 patients randomised to olanzapine, standard olanzapine tablets were non-randomly and consecutively prescribed to the first 19 patients, with the orally disintegrating formulation being prescribed to the following 19 patients.
Results: After 6-week treatment with olanzapine, a significant higher increase in weight was noted in those patients on standard tablets (mean weight increase 6.3 +/- 1.9 Kg) as compared to those on orally disintegrating olanzapine (mean weight increase 3.3 +/- 3.2 Kg) (F = 7.7; p = 0.009). BMI increase was also significantly higher in the olanzapine tablet group (mean increase of 2.1 Kg/m(2) as compared with 1.1 Kg/m(2) in the orally disintegrating group) (F = 4.7; p = 0.036). Substantial weight gain (SWG) (> or =7% increase from baseline weight) was noted in 84.2% (n = 16) of the olanzapine tablet patients and in 31.6% (n = 6) of the orally disintegrating olanzapine patients, with the olanzapine tablet group showing a significant increase in the mean percentage of weight gain (F = 4.0; p = 0.014).
Conclusions: Partial sublingual absorption occurring with orally disintegrating olanzapine may bypass gastrointestinal metabolisation and hence lead to differences in metabolite versus parent compound ratios. However, the need arises to replicate the present study with a longer follow-up.