<prompt> What is the best time to give oral psoralen with UVA?Half n hour before UVA1 hour before UVAHalf n hour after UVA1 hour after UVA  <response>: Ans isb i.e. 1 hour before UVA Psoralens mostly 8- MOP is given orally 1-3 hours average 2 hours before exposure to UVA. 