What hour of the day can I start taking Nyquil cough syrup? 5:00 pm and on or 8:00 pm and on?

Hi yoshiee,
I would take it about an hour before bedtime. Chuck is right about possibly feeling next day drowsiness. I never had a problem but everyone is different.
Have you tried any meds for insomnia?
Melatonin is OTC for people with occasional insomnia.
Are you practicing all the sleep good habits ?
Google insomnia and you will be amazed at how little things that you do out of habit will affect sleep.
I can post them if you would like.
Be well
:-)
Btw... insomnia leads to hypertension, obesity, depression and anxiety.
It is when the body and mind heal themselves so please take it seriously.
:-)

yoshiee; sounds like you are using it mainly for sleep or symptoms, Really either time would be fine but make sure you don't take it when you are going to be out and about. because of the sedation etc.