Yes and No... mostly yes, most manufacturing sites are outside the US.
Pharmaceutical drugs in general
Looking first at pharmaceutical drugs in general there is the FDA Safeguarding Pharmaceutical Supply Chains in a Global Economy from October 30, 2019.
To quote:
The United States, through its investment in biomedical research, has become a world leader in drug discovery and development, but is no longer in the forefront of drug manufacturing. Historically, the production of medicines for the U.S. population has been domestically based. However, in recent decades, drug manufacturing has gradually moved out of the United States. This is particularly true for manufacturers of active pharmaceutical ingredients (APIs), the actual drugs that are then formulated into tablets, capsules, injections, etc. As of August 2019, only 28 percent of the manufacturing facilities making APIs to supply the U.S. market were in our country. By contrast, the remaining 72 percent of the API manufacturers supplying the U.S. market were overseas, and 13 percent are in China. (See Figure 1) FDA’s data show that the number of registered facilities making APIs in China more than doubled between 2010 and 2019.
and here is an image they show

According to the above congressional testimony, 28% of manufacturing is currently done in the US, but manufacturing is trending towards other countries doing the manufacturing.
Antibiotic drugs specifically
This is a bit harder to find good sources.
According to drugs.com the 10 most common Generic Antibiotics are
- Amoxicillin
- Doxycycline
- Cephalexin
- Ciprofloxacin
- Clindamycin
- Metronidazole
- Azithromycin
- Sulfamethoxazole
- Amoxicillin and clavulanate
- Levofloxacin
The following section is to provide references, I have not fleshed them out. I will try when I have some more time.
In regards to Amoxicillin:
drugbank.ca Manufacturers Not Available
This paper from 2015 compares quality of Amoxicillin purchased in different locations, that were originally manufactured in 6 countries (China, Ghana, India, Ireland, Nigeria, and the United Kingdom). It is striking that despite 1.34 billion prescriptions being dispensed in the US, no manufactures from the US were tested - this leads me to thinking there is no manufacturing of Amoxicillin in the US.
In regards to Doxycycline:
drugbank.ca lists 35 manufacturers.
In regards to Cephalexin
drugbank.ca lists 20 manufacturers.
In regards to Ciprofloxacin
drugbank.ca lists 39 manufacturers
In regards to Clindamycin
drugbank.ca lists Manufacturers as Not Available
In regards to Metronidazole
drugbank.ca lists 33 manufacturers
In regards to Azithromycin
drugbank.ca lists 17 manufacturers
In regards to Sulfamethoxazole
drugbank.ca lists 7 manufacturers
In regards to Amoxicillin and clavulanate
Not found on drugbank.ca
In regards to Levofloxacin
drugbank.ca Manufacturers Not Available
Where does big pharma manufacture
There are several companies that seem to make almost all of these antibiotics, namely Pfizer, Pliva, Teva pharmaceuticals and Mylan pharmaceuticals.
Pfizer claims to have some US manufacturing, however the website does not list any pfizer manufacturing plants.
Pliva appears to be Croatian and since their website is not English, I will conjecture this means they have no sites in the US.
Teva says this on their FAQ about Where are Teva products made
A. As the largest generic manufacturer in the world, Teva is able to offer more generic prescription medications than any other company. In fact, one out of every eight generic prescriptions in the United States is filled with a Teva product!2 We use approximately 30 different Teva facilities to manufacture our products. Many of our products are made in North America and by our parent company in Israel.3 The FDA inspects each of our facilities (inside and outside of the United States) to ensure our products meet the same FDA standards of good manufacturing practices as brand-name medications.
Mylan
This Bloomsberg article shows pictures of manufacturing facilities in India and says
Mylan is the world’s second-largest manufacturer of generic drugs, and though it’s run from Canonsburg, Pennsylvania, its operations three hours inland from Mumbai exemplify the central role India has come to play in the global generic-drug industry.
Proof that some manufacture occurs in the US
If we look at the antibiotic drug azithromycin (generic name for the Zithromax name brand made by Pfizer), which was developed outside of the US in the 1980's but whose patent expired in 2005, meaning there are now generic drugs available from companies other than Pfizer, we see some have manufacturing facilities in the US.
Generic companies making suspension/oral doses azithromycin (zithromax):
- Amneal Pharms LLC, Headquarters: New Jersey, US. They have manufacturing facilities located in New York, New Jersey, California, as well as 4 in India amneal.com manufacturing
- Aurobindo Pharma LTD: Headquarters: Hyderabad, India. Marketing partners are AstraZeneca and Pfizer (Pfizer is the original patent holder of azithromycin).
- Epic Pharma LLC: Headquarters: Laurelton, New York. Operates a 100,000 square foot facility, which appears to be the Sandoz facility located also in Laurelton, NY. Also, they are looking for a chemist to work there right now.
- Pliva: Headquarters: Zagreb, Croatia (known being one of the largest producers of Adderall). Manufacturing facilites are located: (website is not in English, will assume in Croatia)
- Zydus Headquarters: Originally India, but has a US headquarters in New Jersey. Manufacturing facilities: Have manufacturing sites in both India and the US. I cannot tell which specific ones make antibiotics from their website.
The 5 above fall into the suspension/oral category. The list of manufacturers for the injectable generic drug is significantly longer.
Conclusions
It is not true that no drugs (antibiotics) are made in the US, however there is a very clear trend that drug manufacture is moving outside of the US. A lot of manufacturing is done in China and especially India. Drugs as a overarching umbrella are only 28% manufactured in the US. Antibiotics statistics are not as readily available as general "drugs" but there are clearly manufacturing done in the US, but it is rare that a company only manufacturers in the US.
From my research, companies seem quick to say they have a site in the US, but it is difficult to get information about what actually happens at the site. This seems to me anyways to give off the appearance of having "token" sites in the US for looks, while producing elsewhere, such as India, which is a common drug manufacture location.