Antibiotics are a group of drugs designed to treat bacterial infections.
The discovery of antibiotics has been one of the most important developments of modern medicine, but this powerful group of drugs is fast becoming a victim of its own success.
What are antibiotics?
Antibiotics (or, more accurately, antibacterials) are a group of drugs designed to treat bacterial infections.
- Although many substances had been found in the past that would kill bacteria, many of these, such as mercury, were almost as dangerous to our own cells.
- Antibiotics work only because bacteria have certain differences from human cells, so they can kill the bugs without hurting us.
Discovery of antibiotics
The first “magic bullet” that would kill bacteria but leave our human cells alone was the antibiotic penicillin, discovered by chance in 1928 by British pharmacologist Sir Alexander Fleming.
Since then other antibiotics have been developed to treat different microorganisms, including many strains of harmful bacteria as well as parasites and fungi.
In just a few short decades, the misuse and overuse of antibiotics have allowed some bacteria to genetically mutate to resist them. Some bacteria, or “super bugs”, are now resistant to all known antibiotics and cannot be treated.
Read more about antibiotic resistance.
When should I take antibiotics?
In New Zealand, antibiotics are available only with a doctor’s prescription.
- They should be taken only as prescribed by your doctor to treat bacterial infections that your natural immune system is having difficulty fighting off.
- You should always take antibiotics according to your doctor’s instructions, making sure to complete the entire course even once you’re feeling better.
- Completing the course is the best way to minimise the risk of the development of bacteria resistant to that antibiotic.
When not to take antibiotics
Unless you have been prescribed antibiotics by your GP as an early treatment for a chronic chest problem, you should not have antibiotics sitting around in your medicine cabinet. You should never take antibiotics that are left over from another illness or have been prescribed for another person.
Antibiotics are not effective against viruses
- Antibiotics will be no help whatsoever against illnesses that are caused by a virus, such as the common cold and influenza.
- Taking antibiotics unnecessarily in an attempt to treat these illnesses and other viral complaints may increase the risk of other bacteria developing resistance.
What are possible risks or side effects of antibiotics?
Different antibiotics affect people differently, but side effects include diarrhoea, nausea, vomiting and fungal infections. Many of these effects can be reduced by taking the medicine as directed, such as after a full meal or with a full glass of fluid.
- A small number of people might have a severe allergic reaction to some groups of antibiotics, such as penicillins.
- Always tell your doctor if you have had an allergic reaction to an antibiotic in the past and, if you can, the name of that antibiotic.
- Care also needs to be taken if you have liver or kidney problems or if you are pregnant or breastfeeding.
- Some antibiotics need to be taken with food, while others require an empty stomach.
- Some don’t mix well with alcohol, while others affect certain other medications, such as the anticoagulant warfarin.
That’s why it’s important to follow your doctor’s instructions carefully.
Commonly used antibiotics in NZ include:
- Penicillin group
- Cephalosporins eg Cefaclor or Cephalexin
- Macrolildes eg Erythromycin, Azithromycin, Roxithromycin or Clarithromycin
- Metronidazole or Ornidazole
- Quinolones eg Ciprofloxacin or Norfloxacin
- Tetracyclines eg Doxycycline