Hopkins ABX Guide


Antibiotics Definition

Antibiotics are a type of medications which are used to treat all sorts of bacterial infections no matter if causing minor health problems or serious and potentially fatal conditions. Antibiotics aren’t effective for infections that are caused by other pathogenic microorganisms such as viruses. Taking antibiotics when not having a bacterial infection not only has no effect on the duration or outcome of the illness but it also increases the risk of antibiotic resistance, that is strains of bacteria becoming immune to the effects of commonly used antibiotics.

Types/Classes of Antibiotics

There are over 100 different types/classes of antibiotics. The majority, however, belong to one of the following major groups: penicillins, cephalosporins, tetracyclines, macrolides, aminoglycosides, sulfonamides and quinolones. Please note that the classification of the main types of antibiotics tends to vary between different sources.

Which Antibiotics?

Which antibiotic are prescribed depends on several factors but it above all depends on the bacteria that are thought to be causing the infection. This is because particular classes of antibiotics are effective only for particular bacteria. A doctor may order laboratory tests to determine which bacteria are responsible for the infection but they may also prescribe antibiotics based on their knowledge for example a specialist doctor may need to be cautious with prescriptions - they know which bacteria are most likely to cause which infections.

Before prescribing antibiotics, a doctor will also consider factors such as pregnancy/breast-feeding, history of allergy to particular antibiotics, overall health, possible interactions with medications if taking any, severity and frequency of side effects, and the severity of the infection. Even if the infection is suspected/confirmed to be caused by bacteria, the doctor may choose not to prescribe antibiotics if the symptoms are mild to moderate and instead, choose the wait and see approach.

Possible Side Effects

All medications can cause side effects and antibiotics are no exception. Possible side effects vary greatly between particular types of antibiotics but the most commonly experienced ones include stomach upset, bloating and diarrhoea.

Taking Antibiotics

In order for the antibiotics to work, it is crucial to take them as instructed by your doctor and complete the prescribed course even if all the symptoms have gone away. Antibiotics are usually taken orally in the form of pills, tablets and capsules as well as liquids, while bacterial skin infections usually involve topical application of antibiotics available in the form of creams and lotions. In case of serious infections, they may also be administered in the form of injection/infusion.