Mucinex and Toddlers

My little girl has a bit of a cold and cough. I took her in today to check her out. The Doctor said that I could give Children's Mucinex 1.25ml 3 times a day. I got the multi-symptom cold have no idea if that's the right one bc she wasn't specific in anything and didn't write anything down. She just said a bunch of things all together and left. I asked the office if they could pull up the chart and write what she said down (it's irritating) has anyone done this? The back of the bottle for 4 and under do not use.