How frequently can you take Dayquil? (3+ Side Effects)

This article will discuss the recommended frequency of taking DayQuil, an over-the-counter cold and flu medication. We will also discuss some potential side effects of overdosing on the medication and what one should do if standard doses fail to provide adequate relief from the symptoms. 

How frequently can you take Dayquil?

You can take Dayquil every 4 to 6 hours, with a maximum of 4 doses in one day. (1) Dayquil is an over-the-counter (OTC) medication that relieves cold, flu, and allergy symptoms. It is available in different formulations to help manage various cold and flu symptoms. 

However, it’s important to take DayQuil mindfully. Even OTC formulations can cause disturbing side effects if not taken properly. The original DayQuil formulation contains three active ingredients (1):

  • Acetaminophen (painkiller and fever reducer)
  • Dextromethorphan (cough suppressant)
  • Phenylephrine (nasal decongestant)

One important thing to note is that DayQuil is available in other formulations which may contain different active ingredients. This is why it’s essential to carefully read the packaging and select the formulation that best suits your needs.

What are the potential side effects of DayQuil?

DayQuil, although it is well-tolerated, can cause some side effects. These include (1):

  • Dry mouth
  • Nausea
  • Headache
  • Dizziness
  • Restlessness
  • Insomnia 
  • Upset stomach
  • Blurry vision
  • High blood pressure (rare)

These side effects can vary from person to person, and some people may not experience a single one of them. However, the chances of getting side effects significantly increase when a higher dose is taken or when the medication is taken more frequently.

What are the risks of overdosing on DayQuil?

Overdosing on DayQuil or taking the medication more often for a long period can cause some potential health risks. As discussed earlier, DayQuil contains three active ingredients, each one of which can affect your body differently when a higher dose is taken persistently. 

Some of the potential risks associated with overdosing on DayQuil include:

  • Liver damage associated with Acetaminophen overuse (2).
  • Psychological side effects, including insomnia, restlessness, hallucinations, etc associated with Phenylephrine overuse (3).
  • Inconsistent changes in blood pressure and psychological side effects associated with Dextromethorphan overuse (4).

What to do if you have taken a high dose of Dayquil?

If you have accidentally taken a high dose of DayQuil and you feel unusual, seek medical attention right away. A minute overdose of DayQuil won’t affect you very much, and you won’t even feel much of a change. 

In case of an overdose, the following points are important:

  • Check the packaging or label for specific instructions or warnings about overdosing on DayQuil.
  • Call your healthcare provider or a poison control centre immediately.
  • Provide important information to your doctor, such as your age, weight, the amount of DayQuil ingested, and the time it was taken. 
  • Follow the instructions and advice of your doctor properly. 
  • Do not take any other medication unless advised by your doctor. 

Remember, it’s crucial to seek immediate medical advice when you have taken more than the recommended dose of any medication, including DayQuil.

It is also important to make sure that you don’t pair DayQuil with similar OTC formulations, like NyQuil. Doing so can increase the chances of side effects.

What to do if DayQuil fails to help your symptoms?

If you find DayQuil ineffective, please reach out to your healthcare provider. Your doctor will recommend some other medication to help your symptoms more effectively. Never increase the dose of DayQuil or start taking it more frequently without medical advice.

There are plenty of medications for cold and flu and your doctor will help you with choosing the right one. 


In this article, We have discussed the recommended frequency of DayQuil administration. We have also talked about some of the potential side effects associated with the overdose of DayQuil and what one should do in such cases. 

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LABEL: VICKS DAYQUIL COLD AND FLU- acetaminophen, dextromethorphan hydrobromide, and phenylephrine hydrochloride capsule, liquid filled. DailyMed [Internet]. Available from:


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