This is a thallium treadmill test? Do contact your doctor's office, but normally beta blockers are not taken from 24-48 hours before the test.
The Thallium TMT is a nuclear test, and beta blockers have been believed to reduce the sensitivity or precision of the test. As a result, they are usually not taken before the test.
Didn't your doctor give you a list of food and drink to limit or stop a certain number of hours before the test?
Normally, before a thallium TMT:
48 hours before:
No beta blockers.
24 hours before:
No caffeine (including in any headache or cold
3 hours before:
No food, water, or tobacco.
Now, this is for the thallium test, which I think is the one you're taking since you said "treadmill" and asked about beta blockers. A stress test
that some take when they cannot take a treadmill test is a simulated stress test. A couple of medications stress the heart without physical exertion in this one. If htis is the one you're taking, then you can and should take all your medications. However, I presume that you are not taking this one from what you say here.
On the other hand, if you are taking a straight stress test, then you should continue to take your medications and simply inform the testing office of your medications.
As I say, double-check this with your doctor's office, but normally you refrain from beta blockers before a Thallium Treadmill Test.