Penicillin 500 mg Give 500 mg qid for Streptococcal, pneumococcal infections, anaerobic infections "above the diaphragm" such as abscessed teeth. Although its spectrum is limited, this drug is relatively cheap and causes fewer side effects such as diarrhea and vaginitis. Unfortunately, streptococci and pneumococci are increasingly resistant.
Amoxicillin / Ampicillin 250 mg Give 250 to 500 mg id for urinary, middle ear, and lower respiratory infection. This is a broader spectrum penicillin. Staphylococci are usually resistant.
Erythromycin 400 mg Give two tablets bid for pneumonia or Streptococcal sore throat. The drug is also of some benefit in Staphylococcal skin infections.
Tetracycline 250 mg Give 250-500 mg qid for plague and various other insect-born infections; urinary infections; bronchitis; infected animal bites; some venereal diseases; Rocky Mountain spotted fever. Avoid this class of drug in pregnant women and young children, if possible.
Doxycycline 100 mg, which is given once daily (twice for severe infections). Doxycycline has fewer gastrointestinal side effects and is better absorbed than tetracycline with food in the stomach, but is more likely to sensitize the skin to sunlight.
Metronidazole 250 mg The usual dose is 500 mg tid, higher for some infections (e.g. amebiasis). The drug is effective against certain protozoans including amoebae and Giardia, and for anaerobic bacteria such as those that normally inhabit the bowel and the female genital tract. It can be extremely useful in intraabdominal , pelvic, and wound infections caused by such bacteria.
Trimethoprim-sulfamethoxazole Give one double strength (DS) tablet bid for urinary infections and some types of bacterial diarrhea, or as a back-up drug for sinusitis, bronchitis, ear infections (for resistant organisms or allergic patients).
How to tell if Abios go bad? http://www.ddponline.org/doxytest.pdf