Posted by Sunnely on August 25, 2000, at 22:51:30
In reply to Re: just started zyprexa and oxazepam, posted by pamela foote on August 25, 2000, at 20:54:01
> just started taking zyprexa about 5 days ago. does smoking have any adverse interaction with zyprexa? thanks,
>
> pamHi Pam,
Yes, cigarette smoking can decrease the effect of Zyprexa (olanzapine), by way of "pharmacokinetic" interaction.
FYI, Zyprexa is primarily metabolized by the liver enzyme called CYP1A2. (Minor roles played by CYP2C19, CYP3A4, CYP2D6, FMO3.) Cigarette smoking induces or stimulates the action CYP1A2. This in turn hastens the metabolism of Zyprexa, leading to a decrease in its blood level, and eventual loss of its effectiveness.
As cigarette smoking can hasten the metabolism, decrease the blood level, and loss of effectiveness of Zyprexa, abrupt cessation of smoking, after a steady-state blood level of Zyprexa has been attained, can lead to decreased metabolism of Zyprexa, leading to increased blood level and side effects.
Other drugs that induce or stimulate the action of this liver enzyme (CYP1A2) and lead to decreased blood level of Zyprexa include carbamazepine (Tegretol), an anti-epileptic and mood stabilizer, and rifampin (Rifadin), an anti-TB medication, and omeprazole (Prilosec) for GERD (gastroesophageal reflux disease). Believe it or not, certain food and vegetables can also induce the action of CYP1A2, leading to decresed blood level of Zyprexa, and loss of its effectiveness. These include charcoal-broiled foods and cruciferous vegetables (e.g., broccoli, cabbage, and brussels sprouts).
As there are "inducers" of CYP1A2, there are also "inhibitors" of this liver enzyme. Drugs that inhibit the action of this enzyme have the potential to decrease the metabolism of Zyprexa leading to increase in its blood level and side effects. These drugs include cimetidine (Tagamet), ciprofloxaxin (Cipro) an antibiotic, fluvoxamine (Luvox) an antidepressant, and tacrine (Cognex) for Alzheimer's disease.
JMHO (Just my humble opinion).
poster:Sunnely
thread:306
URL: http://www.dr-bob.org/babble/20000822/msgs/43748.html