Zyprexa Drug Interactions
Taking certain medications along with olanzapine drugs can increase your risk of experiencing side effects. Zyprexa may also reduce the effectiveness of other medications.
Significant Drug Interactions
Some of the medications that are known to cause significant drug interaction when taken with Zyprexa include:
Antifungal Medications: Ketoconazole can potentially increase the amount of Zyprexa in the blood, possibly increasing the risk of side effect. Patients taking these medications together may require dose adjustments.
- Ketoconazole (Nizoral)
Antihypertensive Medications: Since Zyprexa can induce hypotension, it can possibly potentiate the effects of certain antihypertensive medications.
Antiparkinson Drugs: Zyprexa can potentially reduce the effects of Levodopa and other dopamine agonists.
- Levodopa (L-dopa, Dopar)
Certain Antibiotics: Taking Zyprexa with ofloxacin or norfoloxacin can lead to increased amount of Zyprexa in the blood, possibly increasing the risk of side effects. Patients taking these medications may require dose adjustments.
- Norfloxacin (Noroxin)
- Ofloxacin (Floxin)
CYP1A2 Inducers: Medications that potentiate the CYP1A2 or Glucoronyl Transferase metabolic pathway can potentially reduce the desired pharmacologic effects of Zypreza. Olanzapine is metabolized or processed through the CYP1A2 route which is potentiated by some drugs. Taking olanzapine along with these drugs can increase the clearance of olanzapine by up to 50% possibly reducing its pharmacologic effects. As such, dose adjustments may be necessary for patients taking any of these medications along with Zyprexa.
- Carbamazepine (Atretiol, Carbatrol, Tegretol)
- Omeprazole (Prilosec)
- Rifampin (Rifadin)
CYP1A2 Inhibitors: Medications that reduce the CYP1A2 or Glucoronyl Transferase metabolic pathway can significantly reduce the clearance of Zyprexa in the body. Concomitant use of Zyprexa with CYP1A2 inhibitors can lead to a significant increase in blood levels of Zyprexa, about 50 to 70%. As such, dose adjustments may be necessary for patients taking any of these medications along with Zyprexa.
- Fluvoxamine (Luvox)
Sedative/Benzodiazepine: Taking diazepam along with Zyprexa may increase the risk of orthostatic hypotension (low blood pressure when in standing position). Patients taking both of these drugs are advised to stand up slowly from sitting or lying position. Meanwhile, patients taking lorazepam IM, another sedative, along with Zyprexa are at increased risk for somnolence or excessive sleepiness.
- Diazepam (Valium)
- Lorazepam (Ativan)
Other CNS (Central Nervous System) Acting Medications: Since Zyprexa causes primary CNS effects, caution should be taken when taking this drug together with other CNS active medications.