What are the side effects of penicillin antibiotics?
Side effects of penicillin antibiotics include
- abdominal pain,
- easy bruising,
- rash, and
- allergic reactions.
Individuals who are allergic to the cephalosporin class of antibiotics, which are related to the penicillins, for example, cefaclor (Ceclor), cephalexin (Keflex), and cefprozil (Cefzil), may or may not be allergic to penicillins.
Serious but rare reactions include
- severe allergic reactions (anaphylaxis), and
- low blood platelet levels (thrombocytopenia) or red blood cell count.
Like other antibiotics, penicillin antibiotics can alter the normal bacteria in the colon and encourage overgrowth of some bacteria such as Clostridium difficile, which causes inflammation of the colon (C. difficile colitis or pseudomembranous colitis).
Signs and symptoms of C. difficile colitis include
What drugs interact with penicillin antibiotics?
Penicillin antibiotics have few important drug interactions.
- Probenecid (Benemid) causes an increase in the amount of penicillins in the body by preventing excretion of penicillin by the kidneys.
- Combining ampicillin with allopurinol (Zyloprim) can increase the incidence of drug-related skin rash.
- Penicillin antibiotics may reduce the effect of BCG live vaccine and typhoid live vaccine.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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