Normally, after eating, your body uses carbohydrate as the main energy source. After a long time hungry, it switches to fat. Zyprexa made the body use fat all the time

SUMMARY: A class effect, to varying degrees; and eating less may not help.


1. Food intake was the same between controls and Zyprexaers. You get these effects even if you eat the same.

2. This effect is shared by other atypicals, in a predictable fashion:


In the fed state, Zyprexa and Clozaril do a massive conversion to fat utilization, Risperdal a medium, and sulpiride minimal covnersion.

In the fasting state:

Geodon has a lesser effect than Zyprexa, and appears to normalize; Abilify and Haldol seem close to normal.

3. These effects are consistent with Lilly's own studies that the majority of weight gain happens in the first month, and not suddenly after a year of use.

4. There is still a hunger component to weight gain that is separate from the metabolic effect. Some drugs will make you hungry, change your metabolism, or some mixture of the two. Hunger appears to be a H1 mediated process (Seroquel, Zyprexa, Clozaril, Remeron, Paxil>Prozac, etc.)

5. The immediate clinical consequence of this information is probably (paradoxically) to tell the patients to eat less sugar.

Unless you dramatically cut fat out of your diet, the body will still churn through what fat you do eat at the expense of carbohydrate. Better, and easier, to reduce the carb load that lingers in your body (and likely ultimately gets stored.)

Why Zyprexa (And Other Atypical Antipsychotics) Make You Fat