Antibiotics 101: How It Works, Types, Benefits & More
- Serious Antibiotics Side Effects
- What's important to consider when taking antibiotics?
- Can the tablets be crushed into smaller pieces to make them easier to swallow?

Antibiotics 101: How It Works, Types, Benefits & More
- Serious Antibiotics Side Effects
- What's important to consider when taking antibiotics?
- Can the tablets be crushed into smaller pieces to make them easier to swallow?
- What food can you take antibiotics with?
- When should you take antibiotics?
- Can you take antibiotics together with other medications?
What is Antibiotics?
Antibiotic refers to any substance that inhibits the growth and replication of a bacterium or kills it outright. Antibiotics are a type of antimicrobial designed to target bacterial infections within (or on) the body. This characteristic makes antibiotics slightly different from the other main kinds of antimicrobials widely used today, such as:
- Antiseptics (skin disinfectant) – used to sterilise surfaces of living tissue when the risk of infection is high, such as during surgery.
- Disinfectants – non-selective antimicrobials that kill a wide range of microorganisms including bacteria. They are used on non-living surfaces, for example in hospitals as well as at home in the kitchen and bathroom.
The fact is bacteria are not the only microbes that can be harmful to us. Fungi and viruses can also be a danger to humans. They are targeted by antifungals and antivirals. Antibiotics on the other hand, only refer specifically to substances that target bacteria. Antibiotics, antifungals, antivirals and chemicals such as antiseptics or anything that inhibits or kills microbial cells are collectively known as antimicrobial.
Almost all antibiotics used today are produced in laboratories, but they are often based on compounds found in nature by science experts. Some microbes, for example, produce substances to specifically kill other nearby bacteria in order to gain an advantage when competing for food, water or other limited resources. Other microbes only produce antibiotics in the laboratory.
The production of antibiotics involves an industrial process of fermentation. The source microorganism is grown in large containers (100,000 – 150,000 liters or more) filled with a liquid growth medium. Microorganisms used in fermentation are often genetically modified from its original form to yield the maximum amounts of antibiotics.
Throughout the process, oxygen concentration, temperature, pH, and nutrient levels must be kept at an optimal level while closely monitored and adjusted whenever necessary. As antibiotics are secondary metabolites, the population size must be controlled very carefully to ensure that maximum yield is obtained before the cells die. Once the process is complete, the antibiotic must be extracted and purified to a crystalline product. This is simpler to achieve if the antibiotic is soluble in organic solvent or else, it must first be removed by ion exchange, adsorption, or chemical precipitation.
The principle governing the use of antibiotics is to ensure that the patient receives just the right one. The target bacterium should be sensitive to antibiotics and it needs to be of a high enough concentration to be effective without causing side effects for a sufficient length of time to ensure that the infection is totally eradicated.
Antibiotics vary in their range of action. Some are highly specific. Others, such as the tetracyclines, act against a broad spectrum of different bacteria. These are particularly useful in fighting against mixed infections and in treating infections when time does not permit sensitivity tests. While some antibiotics, such as the semisynthetic penicillins and the quinolones can be taken orally, others must be given by intramuscular or intravenous injection.
Types of antibiotics
Although there are hundreds of different types of antibiotics, most of them can be classified into six groups.
- Penicillins (ie: penicillin, flucloxacillin, amoxicillin, co-amoxiclav and phenoxymethylpenicillin) – widely used to treat a variety of infections such as skin infections, chest infections and urinary tract infections
- Cephalosporins (ie: cephalexin) – used to treat a wide range of infections including more serious infections, such as septicaemia and meningitis
- Aminoglycosides (ie: gentamicin and tobramycin) – specifically used in hospitals only to treat very serious illnesses such as septicaemia. This is due to their serious side effects such as hearing loss and kidney damage. They are usually given by injection but may also be given as drops for some ear or eye infections
- Tetracyclines (ie: tetracycline, doxycycline and lymecycline) – are commonly used to treat acne and a skin condition called rosacea but also effective for treatment of a wide range of infections
- Macrolides (ie: azithromycin, erythromycin and clarithromycin) – are effective in lung and chest infections treatment as well as an alternative for people with a penicillin allergy, or to treat penicillin-resistant strains of bacteria
- Fluoroquinolones (ie: ciprofloxacin and levofloxacin) – are broad-spectrum antibiotics that were once used to treat a wide range of infections, especially respiratory and urinary tract infections. But these antibiotics are no longer used routinely due to their risk of serious side effects
Other antibiotics include chloramphenicol (used for eye and ear infections), trimethoprim (used for urinary tract infections) and fusidic acid (used for skin 