How Long For Infant Tylenol To Work

How Soon Does It Take for Infant Tylenol to Start Working? Phillips says that it takes thirty minutes for Infant Tylenol to start working and that it will reach its peak effectiveness after an hour has passed. Call your child’s paediatrician if the fever subsides for more than twenty-four hours and then reappears, or if the fever persists for more than seventy-two hours in your child.

Acetaminophen, more commonly known by the brand name Tylenol, is an old standby that you most likely keep in your own handbag or medicine cabinet to fight headaches, pain, and fever. Now that you are a parent, it may be the first thing you grab at the drugstore when baby is feeling under the weather. However, administering any kind of medication to a baby, especially one as young as a newborn, calls for additional caution and direction. In order to administer Infant Tylenol in a way that is safe and effective, the following information is required.

In this article:
Infant Tylenol dosage chart by weight
When should you give Infant Tylenol?
What age can you give baby Infant Tylenol?
How long does Infant Tylenol take to work?
How to safely give Infant Tylenol

First, the basics: Acetaminophen is one of two main types of over-the-counter pain relief. The other is nonsteroidal anti-inflammatory drugs (NSAIDs), a category that includes ibuprofen, naproxen and aspirin—though aspirin should never be given to children under 18 unless directed by a doctor, because it could cause a potentially life-threatening disease called Reye’s syndrome.

Infant Tylenol used to be offered in two distinct forms: infant drops, which are intended for use with younger children, and an oral suspension, which is intended for use with older children. The drops contained a higher concentration of medication per milliliter, which meant that parents would only need to give their infants a very small amount. However, there were concerns that this could lead to accidental overdoses, which resulted in the drops being phased out in the year 2011. Now, just like Children’s Tylenol, Infant Tylenol is available as an oral suspension. This form of the medication has a lower concentration of the active ingredient, which makes it possible to administer much safer doses of Infant Tylenol. The concentration of infant acetaminophen should be listed on the bottle as 160 mg/5 mL. This will ensure that you are purchasing the most recent and up-to-date formulation available. And if you still have some of the drops in your medicine cabinet from an older sibling’s supply, you should throw them away and purchase a fresh bottle of the oral suspension instead.

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Infant Tylenol Dosage Chart by Weight

You will find that the label for the bottle of Infant Tylenol does not provide dosage information for children younger than 2 years old. Instead, it instructs you to contact your physician for more information. There is no age that is considered to be too young to administer the medicine as long as you first consult with your doctor to get the correct Infant Tylenol dosage. In fact, Infant Tylenol is sometimes even given to preemies. As long as you consult with your doctor first to get the correct Infant Tylenol dosage.

Your child’s pediatrician will be able to make a recommendation as to whether or not the medicine should be given to baby, as well as what the appropriate dosage of Infant Tylenol should be based on the weight of your child. Wendy Sue Swanson, MD, a pediatrician based in Wisconsin, suggests that parents review the appropriate dosage at every well-baby checkup, depending on the current weight of the baby. “I recommend that parents review the correct dosage at every well-baby checkup,” she says. “The dosage should be written down on a piece of sticky paper, and then the paper should be attached to the bottle.” Once the child has reached the age of 2, you are free to proceed with following the instructions on the bottle.

According to the American Academy of Pediatrics, the following are the current Infant Tylenol dosage guidelines that your doctor will most likely advise you to follow for the 160 mg/5 ml syrup oral suspension formulation in the event that you do find it necessary to give your child Infant Tylenol:

When Should You Give Infant Tylenol?

“Acetaminophen is great for when your baby is in pain, like when they’re teething, have an ear infection or have a minor injury,” Swanson says. When baby has a viral infection or cold, she prefers Infant Tylenol over ibuprofen, since ibuprofen may cause side effects like an upset stomach (although it’s not common).

If baby is under 3 months old and has a fever, always call your doctor immediately before giving your child any medication. “We always like to see the baby before dosing with medicine,” Swanson says. “First of all, we want to know why the baby is crying and feverish—infection can spread more rapidly in an infant than in an older child. Secondly, we need to know exactly how much the baby weighs so you can give the correct dose.” She adds that for babies over 6 months old, a day or two of fever isn’t completely dangerous. “We use medicine to decrease any discomfort your baby feels, not to change the number on the thermometer.” If, however, any child’s fever is over 103 degrees Fahrenheit (39.4 Celcius) or symptoms don’t improve after three days, you should always call your doctor.


One time you don’t want to give Infant Tylenol? Before baby goes for shots. In the past, doctors would recommend giving baby Infant Tylenol before a vaccination to help prevent pain and a possible fever from developing, but that’s changed. “There is new data showing that if you give the child a dose of acetaminophen before the shot, it may make the immunization less effective,” Swanson says. And as for that low fever baby may run after being vaccinated, well that’s just a sign the body’s immune system is kicking in properly, and it usually doesn’t need to be treated. If baby seems fussy and uncomfortable after she’s gotten her shots, though, you can go ahead and give her Infant Tylenol, Swanson says.

How Often Can You Give Infant Tylenol?

You may give baby the correct Infant Tylenol dosage every four hours, but no more than five times in one 24-hour period, says Alexis Phillips, DO, a pediatrician in the Houston, Texas, area. “Do not exceed 48 hours at maximum dose,” she cautions. “Also, Tylenol should not be taken more than seven days in a row without discussing it with your pediatrician.”

How Long Does Infant Tylenol Take to Work?

Infant Tylenol takes 30 minutes to start working, Phillips says, and will reach maximum effect after one hour. If baby’s fever goes away for more than 24 hours and then comes back, or if baby has a fever for more than 72 hours, call your pediatrician.

How to Safely Give Infant Acetaminophen

Ready to help baby feel better? Follow these tips to make sure you medicate baby safely.

• Make sure you have baby’s correct weight To ensure you’re giving baby the correct Infant Tylenol dosage, you need to know how much your child weighs. “If you haven’t been to the doctor in a while, place your child on the scale at home,” Phillips says. (You can also stand on a scale holding baby and subtract your own weight fr

• Carefully read the instructions on the bottle
That means turning the bathroom light on, even if it’s in the middle of the night (also important for measuring the correct dose). Then shake well to evenly distribute the active ingredients.

• Use the right measuring device
Once you’ve figured out the correct Infant Tylenol dosage (based on your doctor’s instructions or the chart above), be sure to only use the measuring device that comes with the bottle—it’s a good idea to always store them together after washing. For infants, it’s usually a syringe. For children 2 and over, it’s most likely a small measuring cup. Since some medications are measured in teaspoons, some in milliliters and some in ounces, never mix and match measuring devices. “You should also never use a kitchen spoon, which isn’t accurate, and you definitely don’t want Grandma just eyeballing it and saying, ‘That looks right,’” Swanson says.

• Keep track of doses
It’s easy to forget when you last gave baby a dose of infant acetaminophen, so make sure to write it down every time. Tylenol even has a handy fever diary app you can download to your phone. It’s especially important to keep track if you have multiple caregivers treating baby—you don’t want anybody accidentally skipping or repeating doses.

• Help baby keep the medicine down
If using a syringe, dispense the liquid slowly into baby’s mouth—aim for the side pocket between the gum and the cheek, toward the rear of the mouth (this is the least taste-sensitive area). If baby spits some of the medicine out, don’t give any more. Instead, wait until it’s time for the next dose and try this trick: Gently squeeze baby’s cheeks together when you dispense the Infant Tylenol—it will open baby’s mouth, making it harder to spit

Updated February 2020

Expert bios:

Wendy Sue Swanson, MD, MBE, FAAP, is a Wisconsin-based pediatrician. After writing the Seattle Mama Doc blog on behalf of Seattle Children’s Hospital for 10 years, she now blogs at She’s also the author of Mama Doc Medicine: Finding Calm and Confidence in Parenting, Child Health and Work-Life Balance.

Alexis Phillips, DO, is a pediatrician with Memorial Hermann Medical Group Pediatrics Atascocita in Atascocita, Texas. She is a graduate of Ohio University Heritage College of Osteopathic Medicine.

How Long Does Tylenol Take To Reduce Fever In Babies?

Acetaminophen is used to reduce fever and treat pain. Your child’s symptoms should get better in 15 to 30 minutes after taking a dose.

Does Infant Tylenol Make Baby Sleepy

The night before last, we were once again having a difficult time. My infant daughter has a lot of mood swings. Today marks the beginning of his 12th week, and I have a feeling that we are about to witness a significant growth spurt. In any case, after attempting everything else I could think of to calm him down, I ultimately decided to give him some Tylenol in the event that he was teething. He passed out and slept for an entire six hours, shattering every record that had ever been set. In most cases, the best we can hope for is three and a half hours. Anyway. I was just curious as to whether or not the Tylenol caused him to sleep for that long, or whether it was just a coincidence…. There is a part of me that wants to believe that this is the beginning of longer periods of sleep, but it’s possible that I’m wrong.

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