Can I use BP 10% during the day and Retin-A 0.05% at night?

You can use BP in the morning and Retin-A at night if you find you are able to tolerate that. Side effects of both include dryness and irritation so I would discuss your plan with your dermatologist who may have you alternate nightly or morning usage to find what your skin responds best to. 

Thank you for your question.Yes BP gel can be used during the day and Retin-A 0.05% at night. However, side effects for both include dryness, irritation, redness, or peeling. I highly recommend you consult with a board certified dermatologist regarding any further questions about your treatment. Take care and good luck.