Gemini - Different people respond differently to medications. As a general rule (or IMHO, or not so humble opinion ) I find that Zyprexa™ (olanzapine) is a more powerful mood modifier than Risperdal™ (risperidone), but at the same time Zyprexa's side effects, at clinically effective doses, are more pronounced and bothersome.

I find Zyprexa is faster acting and can be used in emergency room situations, such as in manic episodes or psychotic breaks, where an effect is needed in a hurry. Zyprexa avoids many of the problems seen with high dose Haldol™ (haloperidol), the usual drug used in these situation.

Over the long term, Zyprexa is more likely to cause weight gain and it's associated problems (eg. hypertension, increased "bad" cholesterol [LDL], etc.) than Risperdal. Also, Zyprexa, in a significant number of cases, results in the development of Type-II diabetes; this is seen with or without an accompanying weight gain. Sedation is another effect of Zyprexa that is not seen as often with Risperdal. That being said, aside from Clozaril™ (clozapine), Zyprexa is the best mood modifier / antipsychotic that we have.

Risperdal has it's own set of problems, most of which arose because when it was introduced the dosages being used were much too high. At first, target doses for Risperdal in psychosis were in the range of 8mg to 12mg. Now we know that needing doses above 6mg per day means that perhaps a change in medications is needed. The main complaint of the older, "traditional" antipsychotics was that they commonly caused movement disorders called extrapyramidal syndrome, or EPS. Over time this could evolve to a permanent condition called tardive dykinesia. EPS could be controlled by using a class of medications called anticholinergics, which had their own set of problems. Risperdal, at doses above 6mg/day, also caused EPS in many people, where Zyprexa rarely causes EPS at any dose. I believe that Risperdal doses should remain under 6mg/day, but there are cases where higher doses are needed.

Another side effect of Risperdal is hyperprolactemia This is an excessive production of prolactin in a non-pregnant woman. Hyperprolactemia can cause a variety of reproductive problems; including irregular or absent menstrual cycles and inadequate production of progesterone during the luteal phase of the cycle. Galactorrhea is a common side affect of hyperprolactemia. This is an excessive production of milk (in non-pregnant women, and yes, sometimes in men), which can be secreted from the nipple by itself or with gentle expression of the nipple. Hyperprolactemia can also cause ejaculation problems in men. I can't remember if hyperprolactemia from Risperdal is totally dose-related, but I do remember that I saw it in people that were taking higher doses.

As I said at the outset, everyone is different and a medication that is a god-send for one person is another's private hell. I like to say that if a med works, stick with it, even if it means the occasional dose increase. In other words, "if it ain't broke, don't fix it."

One more or less reassuring fact with Zyprexa is that the increase in weight from it usually peaks after about a year on the medication, and any dose increase after this does one seldom see more weight gain.

I could probably go on for quite a while, but I have to move on. Sorry - Cam