My Father (98 Yrs) Is On Finasteride, Just Started Last

My father (98 yrs) is on Finasteride, just started last week and my sister just called to say that he has a small amount of blood in his urine. He is currently catheterized and had some blood approx 4 weeks ago but treated w/ antibiotics and it cleared up. Should we be concerned and contact his Dr? Side effects listed for this medication does not say anything about blood in urine. Thanks.