Can I take NyQuil while I'm on 10mg celexa (citalopram)?

No. See reference from drugs.com:Using doxylamine together with citalopram may increase side effects such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience some impairment in thinking and judgment. Why you need celexa. Please visit www.ehacstl.com and see how propose to treat the cause of cerebral symptoms .