Antibiotic Dosages


We are from the U.S. but are currently living in Buenos Aires, Argentina. We have a 9 month old daughter who currently has a double ear infection. The Argentine doctor has prescribed her Amoxicillin, and on the box it states that each dose (5 ml) contains 250 mg of Amoxicilina. In Spanish it states: “Cada dosis (5 ml) de suspension preparada contiene Amoxicilina (como trihidrato) 250 mg.” The doctor indicated that we give her 2.5 ml (1/2 teaspoon) three times a day. Our daughter weighed in yesterday at 8.4 kg (approx 18.9 lbs). When we were in the US this last February, a US doctor prescribed Apothecon Amoxicillin 125mg/5ml for a previous ear infection. 3/4 teaspoon, three times a day. I don’t remember her weight then. My question is: Is the concentration and dosage of the Argentine prescription the same as you would prescribe in the US? Being in a different country from home, we sometimes have our doubts. I’d really appreciate your help.
Buenos Aires, Argentina

Dr. Greene's Answer

I can certainly understand your concern and confusion over the drug dosages given to your daughter. Medication errors can be a real problem. The issues you’ve raised aren’t restricted, though, to crossing national boundaries. I frequently hear the same concern from parents who have just gone across the street to our after-hours pediatric service or down the hall and seen another doctor in my own practice. Today, I met two adorable twin girls who had just moved here from Oregon. When I prescribed amoxicillin, I learned (when Mom asked about the dose) that the dose was different (less) than they had received before.

Many adult medications come in “one-size-fits-all” formulations. With most medicines for children, however, the dose varies with the child’s weight. Because the weights of children change a great deal with the years, these medicines often come in a variety of forms. Many of the liquid antibiotics come in two different concentrations. As you’ve noted, amoxicillin comes in 125 mg per teaspoon (5mL) or 250 mg per teaspoon (5mL). One teaspoon of the 125 mg strength is equal to one-half teaspoon of the 250 mg strength of the amoxicillin. (So in your case, your daughter got a slightly higher dose this time than previously.) The different concentrations make it easier to measure the appropriate amount to give to smaller children, while making sure that larger children don’t need to swallow too much liquid in order to get the correct dose.

In addition to the difference in strengths of the two formulations, there is a wide range of correct dosages for amoxicillin. The dose recommendations for children on amoxicillin range from 20 to 90 milligrams per kilogram of body weight per day . Thus two children could be on appropriate doses of amoxicillin, each weighing the same amount, and yet one is receiving over four times as much as the other.

Physicians will select where to dose a child, within the acceptable range, based on several factors:

  • The individual history of the child
  • The type of infection being treated
  • The physician’s personal philosophy of antibiotic usage

As you might expect, smaller doses are not quite as powerful as the larger doses, but have the advantage of fewer side effects. If a child has had a history of problems with diarrhea or yeast infections, a physician might opt for a lower dose. If the child has had a history of infections that don’t clear up easily, but the child has not had much in the way of side effects, a physician might opt for the larger end of the dosing scale.

Also, different infections tend to be treated at different ends of the dosage spectrum due to the antibiotic’s ability to fight a particular infection. While strep throat can make children very sick, it is an easy infection to clear using the correct antibiotics. Amoxicillin kills strep throat readily, and a 20 mg per kg, per day dosage should be sufficient. With more stubborn infections, such as ear infections, the 40 mg per kg is a standard dose. But whenever resistant bacteria are suspected, high dose treatment with 60 to 100 mg per kg per day might be best. These high doses might also be important for serious bacterial infections.

Most scientific studies of amoxicillin’s effectiveness have used a regime of three times a day for ten days. While this remains the standard, some studies have shown advantages of three, five, or seven day courses. Also, there has been some success with once or twice a day dosing of amoxicillin (The Pediatric Clinics of North America, December 1996).

With all this to consider, there is a final point which is somewhat subjective — an individual physician’s personal approach to antibiotic use. Some physicians like to give the smallest amount of antibiotic that might work, in hopes of avoiding side effects, and maximizing the role of the child’s immune system in fighting the infection. Others physicians like to blast things out with the largest doses acceptable in hopes that they will actually use fewer antibiotics in the long run by killing the infection as quickly as possible.

As you can see, there are a wide range of options for amoxicillin that are all acceptable. You know your child’s past history better than any physician will ever know it (after all, you are the one to clean up after a bout of diarrhea!). You also may have an opinion on how aggressively you want to use antibiotics with your child. Because of this, it is a good idea to question your physician whenever there is a concern about your child’s drug doses. This is particularly true if the dosage has changed. Probably it will turn out to be appropriate, but if it doesn’t, you’ll be glad you asked.

N.B. Although I have used amoxicillin as the example in this answer, the same principles are true for other drugs. You are your child’s most profound advocate. It’s okay to question your physician any time you are not confident that your child is getting the best possible medical care available.

Medical Review on: September 04, 2009
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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Recent Comments

Hello . My Baby is just 3weeks old and he have a ear discharge . Can i know how much dosage should i gave him i have a Co-Amoxiclav here in the house 70mL 400mg/ 57mg per 5mL. He’s weight is 4.3 kl. Please reply thankyou

My son was diagnosed w strep throat an the doctor prescribed Amoxaciolian 6-5. And I don’t know how much that is. Can anyone help me with this????

Two teaspoonfuls of 2.5 ml daily, distributed in two intakes.
What does this mean?
Is a teaspoon 5ml?
Was the word teaspoon a mistake?
I want to know how to interpret this dosage from a tresorix medicafion to my child who is 35 months. Can you please help me?

tea spoon can not be the standard measuring unit so it’s surely mistake

Hi Queeny,

Thanks for writing in.

In the Q&A above, Dr. Greene explains that there are two different concentrations of some medicines. This can be extremely confusing and has led to overdosing in some baby and children’s medications.

Parents need to check the concentration of the medication they have and follow their doctor’s instructions. These should be written on the medication bottle from the pharmacy.

In you case, if the bottle says two teaspoonfuls of 2.5 ml that likely means you have the 2.5 ml concentration. The total dose is 2 teaspoons per day, split into two different doses.

If you have any question, it would be wise to clarify with your doctor when their offices are open.

Best, @MsGreene
Note: I am the co-founder of, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

My daughter hav 8 months she weight 6kg can also give 250 milligrams of amoxicillin syrup?

Hi, thanks for writing in!

This dose is within the typical safe limits that Dr. Greene mentions above. Is that what your doctor prescribed?

Alexandra (caring helper at, not a doctor)

My baby is 10 months old and weighs 19 pounds. He has ear infection in both ears. He has no other symptoms. I am not sure what caused it. I breastfeed laying down at nights. Iam not sure if that caused it. He was prescribed 250 mg per ml. 5 ml twice a day for 10 days. Is this dose high? He is gagging and vomiting since I started dose. Please help

My daughter is 13 weight is 125 5″4

Liquid Amoxicillian for a tooth infection

Proper dosage?

Good day! I found this page very helpful to us moms. Thank you very much. Now I wanna ask if how much dose shall I give to my 1 year old son weighing 12 kilos in a 125mg/5ml suspension if I am going to give him 60mg per day?

Your response is highly appreciated. God bless :)

My doctor prescribed my 4 year old son (40Lbs) 10.5 ml of ammoxicillin 2xdaily for 10 days. Is this safe? it seems like an awful lot.

I wanted to know my 3 year old was prescribed amoxicillin 250mg/5ml 14ml twice a day how much is that in tsp

Hi! I’m really worried. A doctor in Mexico prescribed my baby nephew – a toddler who’s really underweight twice the maximum dosage (due to age and weight) of an anti-biotic. He changed the recipie from one that has to be taken twice a day to the other one, but did not correct the dosage. My main concern is even the vile in the box says DO NOT exceed 5 mg a day. How can my nephew be affected by this? Is it dangerous?

My dughter is 6 years old , so what is the dose of amoxicillin for her , and her weight is 45 lb apparently

Cuanto de amoxicillin 250mg /5ml le puedo dar a mi hija de 2 años y a mi otra hija de 4 años ?

My daughter turned 1 on January 20th. She had a temperature of 39 degrees yesterday afternoon and we took her to her Dr. He told us she had ear infection in both ears and her trought. He prescribed augmentine syrup 5ml and told us to give it to her right away, then again in about 8 hrs time. Then after only twice a day for 6 more days. Will the eight hours difference dosage create a problem?

The pharmacy did give me a measuring spoon for my ddaughter antibiotic and they want her to have 3 milliliters of the antibiotic so how do I go by that with a spoon?

The pharmacy should give dosing spoons with children’s medicine. These spoons have a tube for the handle, and there are marks on the tube. With that kind of spoon, there should be marks for milliliters. If they just gave you a regular spoon, it’s much more difficult. 5 milliliters is very close to one teaspoon. 3 MLs is between 1/2 and 1 teaspoon. In a pinch, you could use a kitchen teaspoon until you can get the correct dosing spoon from the pharmacy.

Hope that helps,
Mom & Executive Producer, (not a doctor)

Help… I am a British aid worker based in rural Madagascar. A young girl has a 9 month old child with a nasty chest infection, my experience with the health care system makes me nervous (11 years and counting) amoxicillin is the standard prescription (I read your earlier post:standard dose 40mg per Kg) but this won’t help the cough and we can’t give honey because of the risks of botulism… What can we do, the coughing is causing weight loss resulting in severe malnutrition, possible death… I have witnessed this before

What is the correct dosage for Cefprozil 250/5ml for my 28lb 23 month old grandson. He has an ear infection in 1 ear.

My daughter is 1 year and 1 month and I recently took her to the doctor and he prescribed her amoxicillin for her ear infection and the instructions says to give her 5ml twice a day up to every 8 to 12 hours for 10 days straight my only concern is if its safe to give her 5ml of amoxicillin she is currently 27lbs and 6 ounces and her height is 31 inches

I gave my som .5 Mls but just notice I was supposed to give him7.5 mls . What should I do?

I have a similar problem.. Im supposed to give my 3month 0ld baby 2.5ml & I give him 0.6… what can i do? his last day for the medication is tomorrow?

I want to ask about atibiotic timing. After my C section I had to take antibiotics on time to prevent infection, which means exactly every 8 hours. Now my baby boy 1 year, 1 month had a cut on his forehead so the doctor told me to give him 2.5 ml 3 times a day. Each 8 hours. If I miss calculated 1 hour before or after, would that be a problem? And for how long should I proceed this ??

My son is 8 months old. The Dr prescribed him amoxicillin. He weighs 21 lbs. It says 400mg/5Ml and under it says take 7.9 milliliters by mouth every 12 hours for 10days. Is that correct ?

It’s important to give the appropriate dose of medicine and children’s doses change by weight. This would be a great time to call your doctor’s office. The nurse will likely be able to clarify the dosage.
I hope that helps.
Best, @MsGreene
Note: I am the co-founder of, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

Hi there I just realized I have made a mistake by giving my 2 year son 5ml of penecilin antibiotics instead of 2.5 .is this harmful to my child

I have a 22 month old who is taken Azithromycin 200/5ml. I was supposed to give him 5ml but accidentally gave him 2tsp. Will this affect him I anyway?? Please help I’m concerned of the dosage mixup. Thanks in advance.

My daughter who is 23 months old, 13kg had this sty on her left eye for 4 days, Shall I give her antibiotic to treat her eye stye? If yes, what is the dosage?

Your immediate response is high appreciated.

Thank you so much