Can You Take DayQuil Or NyQuil With Zyrtec-D?

When looking into potential interactions between any drugs, it is important to consider all of the active ingredients involved.

This is especially true with combination ingredient products, like DayQuil, NyQuil, and Zyrtec-D.

Unfortunately, as it concerns the three products in question (Zyrtec-D, NyQuil, and DayQuil), they all share at least one drug in the same classification, and generally shouldn't be combined on a consistent basis.

Zyrtec-D Active Ingredients

Zyrtec-D contains two active ingredients:

• Cetirizine
• Pseudoephedrine

Cetirizine is a 'second-generation' antihistamine, which are known for their long duration of action and lack of sedative effects (when compared to first-generation antihistamines).

Pseudoephedrine is a nasal decongestant. It is also the active ingredient in 'Sudafed'. All pseudoephedrine products must be purchased behind the pharmacy counter after the passing of the Combat Methamphetamine Act of 2005.

Zyrtec-D is available in 12-hour and 24-hour formulations.

DayQuil Active Ingredients

DayQuil contains three active ingredients:

• Acetaminophen
• Dextromethorphan
• Phenylephrine

Acetaminophen is an analgesic and the active ingredient in Tylenol.

Dextromethorphan is a cough suppressant.

Phenylephrine is a nasal decongestant, similar to pseudoephedrine. Unlike pseudoephedrine, phenylephrine products are available over the counter.

DayQuil also comes in a 'Severe' formula, which contains four active ingredients:

• Acetaminophen
• Dextromethorphan
• Phenylephrine
• Guaifenesin

NyQuil Active Ingredients

NyQuil contains three active ingredients:

• Acetaminophen
• Dextromethorphan
• Doxylamine

NyQuil contains the sedating antihistamine doxylamine. Doxylamine is a first-generation antihistamine, similar to Benadryl and is the ingredient responsible for making you drowsy.

Like DayQuil, NyQuil also comes in a 'Severe' formula:

• Acetaminophen
• Dextromethorphan
• Phenylephrine
• Doxylamine

Zyrtec-D With DayQuil

All DayQuil products (DayQuil and DayQuil Severe) contain phenylephrine, a nasal decongestant. Since Zyrtec-D also contains a decongestant (pseudoephedrine), they generally aren't recommended together.

Nasal decongestants, especially when more than one is taken, can increase blood pressure and the risk of cardiovascular complications (e.g. palpitations).

Additionally, high doses of nasal decongestants can cause nervousness and insomnia.

If you are looking to take DayQuil for symptomatic cold/flu relief, it would be recommended to take it with Zyrtec, not Zyrtec-D. Zyrtec only contains an antihistamine (cetirizine) and is safe to take with DayQuil.

Zyrtec-D With NyQuil

NyQuil contains doxylamine, a sedating antihistamine.

Since Zyrtec contains cetirizine, another antihistamine, use together would be considered a therapeutic duplication.

As you would be taking two antihistamines if these products are combined, the risk of side effects increases. Side effects include:

• Excess sedation
• Dry mouth
• Dry eyes
• Constipation

Having said the above, your doctor may recommend taking NyQuil occasionally, only as needed, even if you are taking Zyrtec-D.

The risk of side effects is generally low and mild in severity. The benefit of an effective cold medication that acts as a sleep aid may outweigh the risks of combining two antihistamines on an intermittent basis. Just be sure to check with your doctor first.

You shouldn't, however, combine NyQuil Severe and Zyrtec-D in most situations.

NyQuil Severe contains phenylephrine while Zyrtec-D contains pseudoephedrine, two nasal decongestants. This interaction is described above in the 'DayQuil with Zyrtec-D' section (combining increases the risk of elevated blood pressure and other side effects).

Final Words

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