Penicillin is an umbrella term for a large family of antibiotics doctors can prescribe to treat infections caused by bacteria. These antibiotics are broad spectrum, working against a variety of organisms, and they are the drug of choice in many infections because their toxicity is low, and they can be highly effective. Some patients have penicillin allergies and sometimes bacteria have resistance to the antibiotic, in which case the patient must take a different medication.
These antibiotics were originally derived from fungi in the genus Penicillium and they work by killing bacteria so they cannot continue causing infection. Penicillin is famous for being among the first antibiotics people successfully developed for medical use, and it made a significant breakthrough in fighting infectious disease during the Second World War. Today, penicillins are available for a number of different kinds of infections, if a doctor believes a patient is a good candidate for treatment with drugs in this class.
Ear, respiratory, and intestinal infections with a variety of bacteria can respond to penicillin therapy. In patients with these infections, a doctor may prescribe an antibiotic first to see if it works, only requesting a culture if the patient does not respond to the treatment. Endocarditis and periodontal infections are also common uses for this drug, and patients with gonorrhea can receive treatment with this medication. Doctors may prescribe the drug for other uses, depending on the specifics of a patient's case and the doctor's experience and prescribing preferences.
Only bacterial infections can be treated with this medication. Viral and fungal infections will not respond, nor will underlying inflammation without any bacteria present. If a doctor is not sure about what is causing an infection, it may be necessary to take a sample for culture to learn more about the situation. Patients should also make sure their doctors are aware of any history of adverse reactions to medication, as allergies to penicillin could be a concern in some patients.
Doctors can give patients oral tablets or injections of penicillin, depending on how fast they need the medication to act. Antibiotic resistance is a prescribing concern. Patients who do not finish their medications can contribute to the development of resistance and over time, this can make it harder to treat bacterial infections because antibiotics will be less useful. When a doctor writes a prescription, it is important to complete treatment and attend a follow-up appointment to make sure the infection is completely gone.