Types of Antibiotics

different classes of antibiotics graphic

Compared with all other types of drugs, antibiotics are the main life rescuers. In less than 100 years of their existence, the antibiotics have saved millions of lives, and this fact may not be underestimated.

What are antibiotics?

It is assumed that there are over 1 million of bacteria types, and a large part of which may be pathogenic. Antibiotics kill or retard the growth of bacteria, and deprive them of their ability to multiply in the body.

Antimicrobial drugs are used for the treatment and prevention of infections, caused by pathogenic microorganisms. List of antibiotics is very large. However, many of the antibiotics are similar in structure, but have different properties, so they are combined in various types.

This review will provide a closer look at the antibiotics classification and their mechanisms of action, the advantages and disadvantages of their action against various types of harmful bacteria.

Beta-lactam antibiotics: Penicillins

These are the most well-known antimicrobial drugs among the first to be sold in pharmacies. It is impossible to calculate, how many people managed to cope with infections due to penicillins. However, some experts believe that penicillins saved the lives of more than 75 million people around the world.

Despite the fact that many bacteria have become resistant to this type of antibiotics, penicillins are still widely used in medical practice.

Depending on their spectrum of activity, several types of penicillins are identified, each of which is used for treatment of different types of infections. However, in general, we can say that all types of penicillins are effective for the treatment of:

  • Infections of the ear, lungs, throat, and bronchial tubes.
  • Urinary tract infections (UTI).
  • Abscesses of teeth and gums.
  • Sinus infection.
  • Sexually transmitted diseases (STDs).

Unlike other types of antibiotics, the penicillins may be used in pregnant women, during lactation, children and infants. Another advantage of this antibiotics type is its low risk of side effects, although they may still be responsible for some allergic reactions.

The list of popular penicillins, which are now sold in pharmacies, includes: Bacampicillin, Amoxicillin, Ampicillin, Augmentin and Carbenicillin.

Beta-lactam antibiotics: Cephalosporins

This type of antibacterial agents has a similar mechanism of action to the penicillins. They are divided into several groups, known as cephalosporins of the first, second, third, fourth and fifth generation.

Indications for the use of oral cephalosporins are similar to those of penicillins. Cephalosporins injectable are reserved for use in hospitals, and are often prescribed for the prevention of bacterial infection before, during and after surgery.

Unlike other types of antibiotics, fifth-generation cephalosporins are effective against MRSA (Methicillin-resistant Staphylococcus aureus). MRSA bacterium is responsible for several difficult to treat diseases in humans and is resistant to many antibiotics.

Today, you can buy antibiotics from the cephalosporins class under the following names: Cefaclor, Cefadroxil, Cefdinir, Cefixime, Cefprozil, Ceftaroline, Ceftibuten, Cefuroxime and Cephalexin.


The macrolides effectively suppress vital functions of Gram-positive bacteria and are restrictedly used for the treatment of infections, caused by Gram-negative pathogens.

Today, the macrolides are recommended for the treatment of strep throat, infections of the mouth, nose, bronchi, lungs and reproductive organs. This type of antimicrobial agents is also often used to treat acne and various skin infections.

When compared with penicillin, the antimicrobial spectrum of macrolides is much wider. Therefore, when penicillins cause side effects, allergic reactions or are inefficient, you may replace them by macrolides.

The cost of penicillins and macrolides is almost identical. Therefore, the replacement of one type to another antibiotic does not increase the cost of the antibiotic therapy.

Pharmacies around the world offer you buying macrolides under the following names: Oleandomycin, Roxithromycin, Solithromycin, Spiramycin, Troleandomycin, Clarithromycin, Erythromycin, Fidaxomicin, Azithromycin or Josamycin.


The action mechanism of the tetracyclines differs from the action mechanism of other antibacterial agents. Tetracyclines do not allow the bacteria to synthesize the protein, thereby preventing their growth and reproduction.

Tetracyclines refer to the type of drugs, known as broad spectrum antibiotics, and are therefore used to treat many infectious diseases. Nevertheless, the tetracyclines are effective against specific bacteria, which multiply only inside the cell. Therefore, tetracyclines are first line antibiotics for the treatment of certain diseases.

Doctors use the tetracyclines most often in patients with severe acne, rosacea, intestinal infections, chlamydia, the respiratory tract infections, as well as for the prevention and treatment of malaria. People on tetracyclines are advised avoiding exposure to sun (to not promote side effects), which may be attributed to their shortcomings.

Today, you may buy in conventional or online pharmacies antibiotics from the tetracycline class under the following names: Doxycycline, Methacycline, Minocycline, Oxytetracycline, Chlortetracycline, Lymecycline or Rolitetracycline.


The first antibiotics in this class have been synthesized over 40 years ago, but still rise a considerable interest. In some parts of Europe and around the world, people buy and use quinolones more often, than other types of antibiotics.

As other synthetic broad-spectrum antibiotics, quinolones are commonly used for the treatment of bacterial diseases (such as bronchitis or kidney infections). However, quinolones act directly on the bacteria DNA. This makes them more suitable for the treatment of some infections.

The antibiotics of this type are particularly effective for the treatment of acute infections of the bladder (cystitis). In many cases, one dose of quinolones is sufficient to get rid of the acute cystitis symptoms.

Quinolones are typically not intended for the bacterial infections treatment in children. Other quinolones disadvantages is the rapidly growing bacterial resistance. In some cases, resistance develops during the treatment course.

If you want to use the class of antibiotics, known as quinolones, you may buy them under the following naming: Ciprofloxacin, Clinafloxacin, Sparfloxacin, Gatifloxacin, Sitafloxacin, Trovafloxacin, Prulifloxacin, Grepafloxacin, Temafloxacin, Nadifloxacin, Gemifloxacin or Moxifloxacin.

What types of antibiotics are the cheapest?

Each class of antibiotics consists of a large number of drugs. Thus, you can not say for sure that one type of the antibacterial agents is cheaper than the other.

However, there are several ways to reduce the costs of the antibiotic therapy.

  • The first way is rejecting branded antibiotics and buying their cheaper generic versions.
  • The second way is to buy all types of antibiotics on the online pharmacy without a prescription.

If the insurance does not cover the cost of antibiotics, order any type of antibiotics online, and it will be delivered to you anywhere in the world, including the US, the UK, Canada, France, or India.