I am looking to mail 50 packets (100 capsules) of antibiotics to the US. Has anyone ever had issues in doing this? Any guidance or advice is welcome. Thank you.

I bet they get confiscated.

Quite likely.

 

"It is prohibited to mail prescription drugs, period. If caught doing so, your package will be seized and destroyed. Only drug manufacturers, pharmacies and other licensed dispensers may mail prescription drugs through the U.S. Postal Service. The only exception is the situation in which you're sending the drugs back to the manufacturer because of a recall or dispensing error.

 

Only entities that are registered with the Drug Enforcement Administration are permitted to send drugs through the U.S. Postal Service. That's how you can order a prescription from a licensed pharmacist and have it arrive in the mail. Mailing prescription drugs is prohibited for citizens except in a few situations. ...The only exception to the "no mailing" rule is when the drugs are recalled, or when the pharmacy sent you the wrong drug or dosage or made another kind of dispensing error. In that case, you can return the drugs, but only to the manufacturer or the manufacturer's agent. Speak to the manufacturer, doctor or pharmacist first, as they must send you a mailing container for the purpose of mailing back the drugs using the USPS "merchandise return" service."

https://legalbeagle.com/7587241-illegal-drugs-across-state-lines.html

 

plus, even if carrying it with you:

 

" A valid prescription or doctors note is required on all medication entering the U.S. "

https://help.cbp.gov/s/article/Article-1160?language=en_US

 

Though in practice if small quantity and non-controlled substance they will usually not bother you about it when in your accompanied baggage