Generally speaking, it is a good idea to check with the doctor
who prescribed the medication before changing the dose. Even with a common and relatively safe medication like Zofran, it is best to do this, because cutting the dose may mean that the medication is no longer as effective for the indication that it was prescribed for. Before doing this, just check with your primary care doctor
, or whoever prescribed the medication!
The second issue to be addressed when cutting or breaking tablets is whether or not this means the medication will be too rapidly degraded by your body. Some medications are coated with a protective substance so that they will not be deactivated in your stomach, and breaking the tablet will prevent this protective coat from working. As a general rule, if the tablet has a score line down the middle, then it is safe to break it in half, whereas if it does not, then it probably needs to be swallowed whole.
Another issue specific to Zofran is that there is an oral dissolving preparation, which is designed to be absorbed in the mouth and can therefore safely be broken into smaller sections. You would need to check with your doctor or your pharmacist to see if the version you have is the oral dissolving preparation, however. Again, please discuss this decision with your doctor.