How long does the drowsiness from Advil PM usually last?
Advil PM is ibuprofen plus an antihistamine (diphenhydramine), which is what causes the sleepiness. For most people, the drowsy effect lasts several hours after a dose. Many users notice they can still feel “hungover” or groggy into the next morning, especially if they took it close to bedtime, used a larger dose, or are sensitive to antihistamines.
When should you avoid driving or alcohol?
Because diphenhydramine can impair alertness, it’s safest to avoid driving and operating machinery until you know how you react. Alcohol or other sedating medicines can make the drowsiness last longer and increase side effects like dizziness, slowed reaction time, and poor coordination.
What factors make drowsiness last longer?
Drowsiness may last longer if you:
- took it late at night or slept less than usual
- are older (many antihistamines cause stronger or longer effects)
- have liver/kidney problems
- take other medications that cause sedation (such as sleep aids, some anxiety medicines, opioids, or muscle relaxers)
What’s the “hangover” feeling the next day?
Even when you wake up, diphenhydramine can linger in your system. If you feel groggy the next day, avoid activities that require alertness and consider not using Advil PM again until you’ve checked with a clinician or pharmacist about a better-tolerated option.
When to get medical help
Seek urgent medical help if you have severe or unusual reactions such as fainting, trouble breathing, severe confusion, or significant worsening drowsiness that doesn’t improve.
Sources
No sources were provided in the prompt for specific duration data, and I can’t reliably cite an exact number of hours for Advil PM drowsiness without an included reference. If you share the exact product strength (or a link to the label you’re using), I can tailor the answer more precisely to that formulation.