Can You take Amoxicillin And Nyquil Together?
Written By Kobi Nathan, Pharm.D., M.Ed., CDP, BCGP, AGSF
Sleep Disorders
January 31, 2024

If you have a bad sinus infection and upper respiratory symptoms, your doctor might prescribe amoxicillin to treat the active infection.

They may also recommend NyQuil to soothe your upper respiratory symptoms and help you fall and stay asleep.

But, how exactly are you supposed to take both medications?

Can you take amoxicillin and NyQuil together?

In this post, I’ll review each medication and share important tips you should know when taking them.

But first, I’ll answer your immediate question:

 Can amoxicillin and NyQuil be taken together?

Yes, it is safe to take NyQuil and amoxicillin together.

There are no known drug interactions between amoxicillin and NyQuil.

These two medications serve different purposes but can be used together under most circumstances.

Now, let’s get into the details about each medication…

What is NyQuil?

NyQuil Cold & Flu Nighttime Relief is manufactured and distributed by Vicks, the well-known and ubiquitous U.S.-based pharmaceutical company.

ZzzQuil is also manufactured and sold by Vicks (Read my post, NyQuil vs. ZzzQuil, to learn the difference between both medications).

NyQuil is an over-the-counter combination medication used to treat the upper respiratory symptoms of the common cold, influenza, allergies, sinusitis (runny nose), etc.

NyQuil contains the following ingredients:

  • Acetaminophen (to manage pain and fever)
  • Dextromethorphan (cough suppressant)
  • Doxylamine (a first-generation antihistamine used to promote sleep)

This potent combination of active ingredients effectively manages cold and flu symptoms.

NyQuil can be taken as needed to manage your symptoms.

My clinical take: Side effects and warnings about NyQuil

Before you take NyQuil, you should be aware of the following anticholinergic side effects and warnings:

  • Constipation
  • Blurred vision
  • Dry mouth
  • Urinary retention
  • Increased sedation (drowsiness) and Fall risk
  • Worsening of Dementia
  • Possible connection to dementia with long-term use (see my presentation slides linked below)
  • Dizziness

These effects underscore the importance of avoiding activities requiring mental alertness, like driving, to prevent accidents and ensure safety.

To really understand how dangerous anticholinergic medications are, especially to older adults, please review the presentation I gave about this class of drugs at Medicine Grand Rounds.

So, I suggest only taking NyQuil for as short a period as possible and avoiding long-term use.

Taking it to manage insomnia is not advisable due to the adverse effects I have noted above.

Taking NyQuil with Benadryl should also be avoided since both medications contain first-generation antihistamines and your side effects will be greatly amplified.

What is amoxicillin?

Amoxicillin is a penicillin-derived antibiotic commonly prescribed to treat bacterial infections in the ear, nose, throat, urinary tract, skin, airways, and lungs.

My clinical take: Common side effects and warnings of amoxicillin

I am sure you have heard this many times before, but it is very important to take your prescribed amoxicillin exactly as directed by your healthcare provider and finish it, even if you feel better before the full course is completed.

This is to kill the bacteria fully and to prevent them from building resistance to the antibiotic.

Amoxicillin may cause the following common side effects:

  • Upset stomach
  • Diarrhea
  • Nausea
  • Vomiting
  • Yeast infection

Consult your healthcare provider for medical advice if any of these side effects do not resolve or impact you significantly.

Also, if you have questions or concerns about taking NyQuil with amoxicillin, talk to your doctor or pharmacist.

Based on your medical history and current health status, they can offer insights into how this combination may affect you.

Remember, every individual’s body reacts differently to medications, making personalized guidance invaluable.

Always consult your healthcare professional before making any decisions about your medication regimen.

They can help you understand the potential risks and benefits, ensuring you make the best health choice.

Moreover, they can advise you on what symptoms to watch for and when further medical attention might be necessary.

Your healthcare provider is your best resource for ensuring your treatment plan is both safe and effective.


In summary, combining amoxicillin with NyQuil is generally safe, with no known drug interactions between them.

It’s crucial, however, to complete your amoxicillin course as prescribed to prevent antibiotic resistance.

While NyQuil can alleviate cold or flu symptoms, be mindful of its drowsiness effect.

Always consult a healthcare professional before starting any new medication regimen.

This ensures your treatment plan is both safe and effective, tailored to your specific health needs.

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