interactions affecting olanzapine
olanzapine is metabolised by CYP1A2, substances that can specifically
induce or inhibit this isoenzyme may affect the pharmacokinetics of
metabolism of olanzapine may be induced by smoking and carbamazepine,
which may lead to reduced olanzapine concentrations. Only slight to
moderate increase in olanzapine clearance has been observed. The
clinical consequences are likely to be limited, but clinical
monitoring is recommended and an increase of olanzapine dose may be
considered if necessary.
a specific CYP1A2 inhibitor, has been shown to significantly inhibit
the metabolism of olanzapine. The mean increase in olanzapine Cmax
following fluvoxamine was 54 % in female non-smokers and 77 % in male
smokers. The mean increase in olanzapine AUC was 52 % and 108 %
respectively. A lower starting dose of olanzapine should be
considered in patients who are using fluvoxamine or any other CYP1A2
inhibitors, such as ciprofloxacin. A decrease in the dose of
olanzapine should be considered if treatment with an inhibitor of
CYP1A2 is initiated.
charcoal reduces the bioavailability of oral olanzapine by 50 to 60 %
and should be taken at least 2 hours before or after olanzapine.
(a CYP2D6 inhibitor), single doses of antacid (aluminium, magnesium)
or cimetidine have not been found to significantly affect the
pharmacokinetics of olanzapine.
for olanzapine to affect other medicinal products
may antagonise the effects of direct and indirect dopamine agonists.
does not inhibit the main CYP450 isoenzymes in
1A2, 2D6, 2C9, 2C19, 3A4). Thus no particular interaction is expected
as verified through in
where no inhibition of metabolism of the following active substances
was found: tricyclic antidepressant (representing mostly CYP2D6
pathway), warfarin (CYP2C9), theophylline (CYP1A2) or diazepam
(CYP3A4 and 2C19).
showed no interaction when co-administered with lithium or biperiden.
monitoring of valproate plasma levels did not indicate that valproate
dosage adjustment is required after the introduction of concomitant
should be exercised in patients who consume alcohol or receive
medicinal products that can cause central nervous system depression.
concomitant use of olanzapine with anti-Parkinsonian medicinal
products in patients with Parkinson's disease and dementia is not
should be used if olanzapine is being administered concomitantly with
medicinal products known to increase QTc interval.
[Summary of Product Characteristics]. Utrecht, The Netherlands: Eli
Lilly Nederland B.V.