<prompt> What is the best time to give oral psoralen with UVA -Half hour before UVA1 hour before UVAHalf n hour after UVA1 hour after UVA  <response>: Ans is b i.e. 1 hour before UVA Oral PUVAo In oral PUVA, 8-MOP is administered orally 0.6 -0.8 mgkg body weight 1 -3 hours before exposureo For 5-MOP the usual dose is 1.2-1.8 mgkg body weight.Topical PUVAo A lotion containing 0.1-1 8-MOP is applied on the affected area and is exposed to UVA either immediately or after 1 - 2 hours.o Alternatively, a vanishing cream containing 0.01 TMP is applied 10-20 minutes before exposure. 