Why does Nyquil make you sleepy

Can I take Nyquil while breastfeeding?


If you are breastfeeding and catch a cold - we will feel for you! And we know you are probably looking for a way to relieve your cold symptoms so you can sleep well. At the same time, however, you want to keep your child safe.

Nyquil products are over-the-counter drugs used to relieve temporary nighttime cold and flu symptoms. These include cough, sore throat, headache, mild pain, and fever. They also include congestion or pressure of the nose and sinuses, runny nose, and sneezing. Certain types of Nyquil are likely to be safe to take if you are breastfeeding, while others come with precautions.

How Nyquil Treats Your Symptoms

Nyquil products contain a combination of the active ingredients acetaminophen, dextromethorphan, doxylamine and phenylephrine. They come in liquicaps, caplets, and liquid forms. Common Nyquil products include:

  • Vicks Nyquil Cold & Flu (acetaminophen, dextromethorphan and doxylamine)
  • Vicks Nyquil Severe Cold & Flu (Acetaminophen, Dextromethorphan, Doxylamine, and Phenylephrine)
  • Vicks Nyquil Cough Suppressant (Dextromethorphan and Doxylamine)

The following table describes how the ingredients work together for different cold and flu symptoms.

Active ingredientTreated symptomsHow it worksSafe to take when breastfeeding?
Paracetamol Sore throat, headache, mild pain, feverchanges the way your body feels pain, affects the body's temperature-regulating system in the brain Yes
Dextromethorphan HBrCough from smaller throat and bronchial irritationaffects the part of the brain that controls coughingYes
Doxylamine succinate runny nose and sneezingblocks the effects of histamine *probably**
Phenylephrine HClCongestion and pressure of the nose and sinuses reduces swelling of the blood vessels in the nasal passagesprobably**
* Histamine is a substance in the body that causes allergy symptoms, including runny nose and sneezing. Blocking histamine also makes you drowsy, which can help you sleep better.
** There are no studies on the safety of this drug while breastfeeding. It's probably safe, but you should ask your doctor before using it.

There are other forms of Nyquil available. Be sure to check the active ingredient label before consuming. They may contain additional active ingredients that may be unsafe for breastfeeding mothers.

Effects of Nyquil on breastfeeding

Each of the active ingredients in Nyquil works differently, and each can act differently on your breastfeeding child.


A very small percentage of paracetamol passes into breast milk. The only side effect reported in breast-fed infants is a very rare rash that goes away when you stop taking the medication. According to the American Academy of Pediatrics, acetaminophen is safe to take if you are breastfeeding.


Dextromethorphan is likely to pass into breast milk and there is limited data on its effects in breastfeeding infants. However, the small amount of information available suggests that dextromethorphan can be used safely during breastfeeding.


Too much doxylamine can reduce the amount of breast milk your body produces. Doxylamine is also likely to pass into breast milk. The effect of this drug on a nursing child is unknown.

However, doxylamine is an antihistamine, and these drugs are known to cause drowsiness. This can make your breastfeeding child tired. Your child may also experience other side effects from the medication, such as:

  • irritability
  • unusual sleep patterns
  • Overexcitability
  • excessive sleepiness or crying

All forms of Nyquil contain doxylamine. Because of the possible effects on your child, ask your doctor whether Nyquil is safe to take while breast-feeding.


This drug is likely to pass into breast milk. However, phenylephrine will be poorly absorbed by your body if you take it orally. So the effects on your child would likely be minor. However, you should speak to your doctor before taking any medications that contain phenylephrine.
Decongestants like phenylephrine can also decrease how much breast milk your body makes. You should watch your milk supply and drink extra fluids if necessary to increase your milk production.

Alcohol in Nyquil

The active ingredients in Nyquil are usually safe. However, the liquid forms of Nyquil also contain alcohol as an inactive ingredient. You shouldn't consume products that contain alcohol while breastfeeding.

This is because alcohol can get through breast milk. If a drug passes into your breast milk, it can cause side effects in your child when you feed them. Your child may experience too much weight gain, changes in sleep patterns, and hormone problems from alcohol flowing through your breast milk.

To avoid these problems, wait two to two and a half hours after breastfeeding after any type of alcohol, including the small amounts that are in liquid Nyquil.

Talk to your doctor

If you experience cold or flu symptoms while breastfeeding, ask your doctor:

  • Are there any medications I can take to relieve my symptoms?
  • Can you recommend a product that does not contain alcohol that will relieve my symptoms?
  • How long can I use Nyquil safely?