I've cooked brown rice many times; I've used my pressure cooker uncounted times. I've never cooked brown rice in the pressure cooker before last night. It works! It made the best brown rice I've ever eaten, bar none.
I found directions in Lorna Sass's book about pressure cooking. After bringing it to pressure, it only took 15 minutes to cook. I did the pressure release under the faucet, drained the rice (reserving the cooking water) and kept the rice warm in the lidded pot with a paper towel between the pot and lid.
I flavored the rice with a spoonful of soup base and some Spanish Saffron before cooking. 5 1/2 C of water to 1 1/2 C of brown rice.