Antibiotics are drugs used to fight bacterial infections and some parasitic infections. They are not useful in cases of viral infections such as the flu, flu-like syndromes and colds that are not triggered by bacteria. Taking antibiotics can help only in cases of bacterial infections. Otherwise, the inappropriate use of antibiotics may cause as much damage to the health by encouraging the emergence of bacterial strains resistant to their action, which are more difficult to defeat. Similar considerations also apply in the case of mycosis, infections triggered by fungi. Antibiotics, in short, should be used only against bacteria and some parasites.


Depending on the mechanism of action it is possible to distinguish different types of antibiotics. The main classes are:


  • Aminoglycosides, such as gentamicin
  • Cephalosporins, such as cefalexin
  • Quinolones, such as ciprofloxacin
  • Lincosamides, such as clindamycin
  • Macrolides, such as erythromycin
  • Nitroimidazoles, such as metronidazole
  • Penicillin, such as amoxicillin
  • Sulfonamide, such as the co-trimoxazolo
  • Tetracyclines, such as doxociclina


In addition, there are several other antibiotics that fight rare infections, such as for example, tuberculosis. Some of these molecules act by killing the germs, i.e. by exerting a bactericidal action. Typically, antibiotics of this type act on the structure of the cell wall. Others, however, prevent bacteria or parasites from reproducing, thus exerting a bacteriostatic action. The exact mechanisms of action can be very different. In addition to antibiotics that inhibit the synthesis of the cell wall, there are also those that prevent the synthesis of proteins, those that inhibit the replication or transcription of DNA, those that alter the cytoplasmic membrane of bacteria and other acting as antimetabolites, which interfere with essential metabolic pathways of the microbe.


The most suitable choice of antibiotic depends on the type of infection and the microbe that triggered it. A doctor knows what are the most effective antibiotics for urinary tract infections and will choose which to prescribe to his patients based on this knowledge. If urine cultures should reveal the presence of a bacterial strain that is resistant to an antibiotic, the choice may also be based on this additional information.


How should antibiotics be taken?


Antibiotics are available in the form of tablets, capsules, or solutions to be taken orally, or solutions for injections. There are also creams, ointments and lotions that allow the topical use of antibiotics, useful in cases of skin infections. Antibiotics should always be used under prescription and by strictly following the doctor's instructions regarding the dosage and mode of application. Not doing so can reduce the absorption of the drug or render the treatment useless, as well as aid the onset of drug resistant microorganisms.


The duration of treatment varies greatly from case to case: urinary tract infections may require a few days of treatment, while pneumonia may require continuous antibiotic therapy for 1 to 2 weeks. On the other hand, bone infections may require treatment of a few months, while acne antibiotic treatments can last even longer.


Contraindications and warnings associated with the use of antibiotics


With the exception of allergic reactions to the drugs, the majority of adverse effects that may be associated with taking an antibiotic are not serious. In most cases, these episodes include diarrhea or nausea. Women may also struggle with vaginal candidiasis due to the effect of the bacterial antibiotic on the intestinal and vaginal flora. The resulting changes in the population of "good" bacteria, can also lead to the appearance of oral thrush.


Moreover, the use of antibiotics may be associated with the following side effects:


  • Abdominal cramping
  • Eczema
  • Loose stool
  • Shortness of breath
  • Swelling of the tongue, lips or face
  • White spots on the tongue
  • Nausea or vomiting
  • Hives
  • Vaginal discharge


In addition to the side effects, it is important to remember the possibility that antibiotics interfere with the action of other drugs. For example, antibiotics may reduce the effectiveness of birth control pills.