The FDA-approved prescribing information for Zyprexa (olanzapine) recommends avoiding drinking alcohol while taking the drug, for a few reasons:
- Alcohol can enhance the CNS (central nervous system) effects of Zyprexa (e.g. sedation and dizziness).
- Alcohol increases the risk of 'orthostatic hypotension', a condition in which blood pressure drops suddenly when going to a sitting or standing position.
The following is what the prescribing information states about the CNS effects:
CNS Acting Drugs — Given the primary CNS effects of olanzapine [Zyprexa], caution should be used when olanzapine is taken in combination with other centrally acting drugs and alcohol.
It says this in regard to 'orthostatic hypotension':
Patients should be advised of the risk of orthostatic hypotension, especially during the period of initial dose titration and in association with the use of concomitant drugs that may potentiate the orthostatic effect of ZYPREXA, e.g., diazepam or alcohol.
It should be noted that the prescribing information for Zyprexa specifically states that alcohol does not affect the pharmacokinetic profile of the drug (i.e. how the drug is absorbed and metabolized etc...) or its effectiveness. What we are concerned about is the increased risk of side effects (as discussed above)
Is It Ever Safe To Drink Alcohol?
Going on to the next part of your question (how long to wait between drinking alcohol and taking a dose of Zyprexa), this is difficult to answer.
Zyprexa is a medication that you need to daily, on a consistent basis, for it to be effective, so you can't really avoid having it in your system if you are looking to have an alcoholic drink.
The CNS (central nervous system) effects and risk of orthostatic hypotension are likely highest soon after taking a dose but that risk doesn't really go away completely, even if you are almost ready for your next dose.
The longer you take Zyprexa, the more likely you are to have built up a tolerance to these side effects, but again, they can still happen, especially when taking something that could exacerbate their occurrence (like drinking alcohol).
Now, this doesn't mean that there isn't a certain time in which you may be less susceptible to an interaction with alcohol.
According to the prescribing information for Zyprexa, after taking a dose by mouth, maximum concentrations of the drug are reached after about 6 hours:
Olanzapine is well absorbed and reaches peak concentrations in approximately 6 hours following an oral dose.
Therefore, after 6 hours, we could assume that you are at the greatest risk of side effects (especially if combined with alcohol).
The problem is that Zyprexa is metabolized fairly slowly, and has an average half-life of around 30 hours (half-life is the time it takes for the body to metabolize 50% of a drug).
This means that there isn't a whole lot of fluctuation in drug concentrations, even after 24 hours (when it is time to take your next dose).
Adding to this, as soon as a week after staring Zyprexa, you will reach a 'steady-state' concentration, where the amount of drug cleared from your body equals how much you put in from daily dosing.
All of this is to say that you can't really avoid having concentrations of Zyprexa in your body that wouldn't interact with other drugs (and alcohol of course).
So overall, the recommendation is to not drink alcohol with Zyprexa due to the increased risk of side effects.
Some people may be fine with an occasional drink in the evening, as long as they take care not to participate in an activity that requires mental alertness (like driving).
Even then though, the risk of orthostatic hypotension is there, which can increase your risk of falls or accidents.
Be sure to follow the advice in the prescribing information on how to best mitigate this:
Patients should be advised to change positions carefully to help prevent orthostatic hypotension, and to lie down if they feel dizzy or faint, until they feel better. Patients should be advised to call their doctor if they experience any of the following signs and symptoms associated with orthostatic hypotension: dizziness, fast or slow heart beat, or fainting.
It is not recommended to consume alcohol while taking Zyprexa due to the increased risk of CNS effects (e.g. sedation) and orthostatic hypotension (i.e. a sudden drop in blood pressure).