I have heard that the generic version of Effexor can have…

Hello -
Thank you for the question.
Generic medications go through a rigorous approval process to ensure that they are equivalent to their branded counterpart. The FDA defines generics as: "a drug product that is comparable to brand/reference listed drug product in dosage form, strength, route of administration, quality and performance characteristics, and intended use." With that said, generics that are approved to that standard are given an "AB" rating by the FDA which is released in the Orange Book. Here is a link to the online tool: http://www.accessdata.fda.gov/scripts/cder/ob/docs/queryai.cfm.
At this site, type in venlafaxine, click the circle "Rx", and hit submit. This will take you to all of the generic formulations of Effexor. When you look at your prescription, you can see who the manufacturer is on the bottle. Find the manufacturer on your bottle in the far right column, and if there is an "AB" rating in column 2, it is deemed therapeutically equivalent. If the manufacturer is not on the list, it is most not likely "AB" rated. If that is the case, contact your pharmacy to either request a manufacturer that is AB rated or provide information stating that it is AB rated.
Lastly, the majority of patients do fine on generic medications. However, there are a few patients that experience differences than the branded counterpart. Since it seems that you have found an equivalent dose that works for you, this is great, especially since the less side effects. There are some that I see that would need to go back to the branded agent, but when cost is prohibitive, we change them to another medication. This is why I prefer to start all my patients on generic medications from the get-go when possible.
I hope this helps!
Thanks.