In the United States, antibiotic medications are available over the counter (OTC) for the treatment of bacterial vaginosis, trichomoniasis, ureaplasma urealyticum, chlamydia, and genital herpes. Antibiotics can be obtained in a variety of ways, including through online pharmacies and prescription delivery services. OTC antibiotics can also be obtained from pet stores for the treatment of certain infections in cats and dogs, as well as other animals. It is important to note that while OTC antibiotics may be available for purchase without a prescription, they should not be used without first consulting a medical professional to determine the underlying cause of the infection and to ensure that the antibiotic is the appropriate choice for the specific infection.

Step 1: Research and gather information about OTC antibiotics
To answer the question, I would first conduct a thorough search on the topic of OTC antibiotics. This would involve looking for information from reputable sources such as government websites, medical journals, and other reliable sources to ensure the accuracy of the information provided.

Step 2: Compile a list of OTC antibiotics
Using the information gathered in step 1, I would create a list of OTC antibiotics that are commonly used in the United States. These could include medications such as Metronidazole (for bacterial vaginosis), Trichomonacide (for trichomoniasis), Urex (for ureaplasma urealyticum), Zithromax (for chlamydia), and Valtrex (for genital herpes).

Step 3: Determine the availability and dosage information of each OTC antibiotic
I would then research each OTC antibiotic on the list to determine the dosage and availability of each medication. This would involve checking various sources such as drugstore websites and medical supply companies to ensure accurate information.

Step 4: Compile a summary of OTC antibiotics
Using the information gathered from steps 2 and 3, I would compile a summary of the OTC antibiotics available for purchase in the United States, including their uses and available dosage information. This summary would provide a comprehensive overview of the available options for those seeking OTC antibiotics.

Step 5: Provide guidance on the proper use of OTC antibiotics
To ensure the safe and effective use of OTC antibiotics, I would provide guidance on the proper usage, dosages, and potential risks associated with each medication. This would include information on when to seek medical attention if symptoms persist or worsen, as well as potential side effects and interactions with other medications.