Patsy,
Thank you for your question.
For most antidepressants, it takes about 4-6 weeks to see the full effect of the medication. However, each medication effects each person differently, so it may take a little less or a little more time to reach the maximum effect for you. In addition, 225 mg is the maximum recommeded daily dose of Effexor (venlafaxine), so if this dose doesn't work for you, you may want to talk to your doctor about trying another medication.
In response to the above answer, increased blood pressure is a known side effect of Effexor, so your doctor should be monitoring your blood pressure at each visit. You can find more information about Effexor here.
Best of luck,
Casey