If you have an infection, it is important to know whether it is caused by bacteria or a virus. Most upper respiratory tract infections such as colds, flu, most coughs, and sore throats are caused by viruses and cannot be treated with antibiotics. If a bacterial infection is to blame, bacteria can multiply and cause symptoms, and the body’s immune system can usually kill them. Our white blood cells attack harmful bacteria and, even if symptoms do occur, our immune system can usually cope and fight off the infection. There are occasions, however, when it is all too much, and some help is needed; this is where antibiotics are useful. Antibiotics, also known as antibacterials, are medications that destroy or slow down the growth of bacteria. If antibiotics are overused or used incorrectly, there is a risk that the bacteria will become resistant – the antibiotic becomes less effective against that type of bacterium. 

How do antibiotics work?
The first antibiotic was penicillin. Such penicillin related antibiotics as ampicillin, amoxicillin, and benzylpenicillin are widely used today to treat a variety of infections. Although there are a number of different types of antibiotics, they all work in one of two ways:
• A bactericidal antibiotic (penicillin, for instance) kills the bacteria; these drugs usually interfere with either the formation of the bacterium’s cell wall or its cell contents.
• A bacteriostatic stops bacteria from multiplying.

Reactions to antibiotics can be very serious, and sometimes fatal.
Antibiotics should be used with extreme caution for the following individuals:
• Anyone with reduced liver or kidney function
• Anyone who is pregnant
• Anyone who is breastfeeding

Common Side Effects
• Diarrhea
• Feeling sick
• Fungal infections of the mouth, digestive tract, and vagina

Rare side effects of antibiotics:
• Formation of kidney stones (when taking sulphonamides)
• Abnormal blood clotting (when taking some cephalosporins)
• Sensitivity to sunlight (when taking tetracyclines)
• Blood disorders (when taking trimethoprim)

Allergy
Some patients may develop an allergic reaction to antibiotics – especially penicillins. Anyone who has an allergic reaction to an antibiotic must tell their doctor and/or pharmacist. Side effects might include:

  • a rash
  • swelling of the tongue and face
  • difficulty breathing 

Interactions
Individuals taking an antibiotic, should not take other medicines or herbal remedies without speaking with a doctor first. OTC (over the counter, non-prescription) medicines might also interact with antibiotics. Penicillins, cephalosporins, and some other antibiotics can undermine the effectiveness of oral contraceptives. If the antibiotic has caused diarrhea/vomiting, the absorption of contraceptives may also be disrupted. Anyone taking these drugs should consider taking additional contraceptive precautions.

How to use
Antibiotics are usually taken by mouth (orally); however, they can also be administered by injection or applied directly to the affected part of the body. Most antibiotics start having an effect on an infection within a few hours. It is important to complete the whole course of medication to prevent the infection from coming back. Stopping the medication before the end of the course means that there is a higher chance the bacteria will become resistant to future treatments.

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