Is it ok to split quetiapine (seroquel) 25 mg ir pill in half? (want to raise my dose gradually)

Yes: The immediate release pill can be cut in half, but the best folks to advise you on what dose to start, and by how much how quickly you can raise it are your prescriber and your pharmacist, and I would urge you to ask at least one of those for advise. Your doctor or other provider should also be made aware of what you are doing with your dose, because that will impact when they see you back.

Seroquel (quetiapine): it is immediate release so it should be OK

Be careful, see DR: You are not stating why you are taking this drug. In the US, there is a warning on this medication being prescribed for persons less than 24 years of age. Are you just starting this medication? It is generally not advisable to cut or split pills which are sustained release (IR form) as this defeats the coating which permits the gradual release of the drug. Please check with your doctor!

Yes: If your doctor has advised a 12.5 mg Seroquel increase to get a therapeutic response, that should be fine. Only change your dosing if recommended by doctor who knows you well and is carefully monitoring your progress. Seroquel is an antipsychotic med requiring close medical supervision. I hope this helps. Best wishes.