You should always inform your doctor and your pharmacist about all medications you take (including over-the-counter) before being prescribed Zyprexa.
Zyprexa may increase the effects of medicines that are used to control high blood pressure. This could lead to very low blood pressure, dizziness, and fainting. Zyprexa may also increase the effects of drugs that cause drowsiness, including antidepressants, alcohol, antihistamines, sedatives, pain relievers, anxiety medicines, muscle relaxants, and any other drug that makes you feel sleepy or relaxed. Zyprexa may decrease the effects of drugs used to treat Parkinson’s disease; this could lead to worsening Parkinson’s symptoms.