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Antibiotics and Antivirals

Human Biology (Year 12) - Prevention and Treatment of Disease

Ben Whitten

What is the difference between antibiotics and antivirals?

Antibiotics are drugs that are used to fight infections of microorganisms, particularly bacteria, whilst antiviral drugs are used specifically for treating viral infections. Antibiotics don't work against viral infections such as colds or the flu. In those cases, physicians often prescribe antiviral drugs, which fight infection by inhibiting a virus's ability to reproduce.

In the case of antibiotics, there are 4 categories you need to be aware of.

  • Bactericidal

  • Bacteriostatic

  • Broad-spectrum

  • Narrow-spectrum

What are the different types of antibiotics?

Bactericidal antibiotics kill bacteria by changing the structure of the cell wall or the cell membrane, or by disrupting the action of essential enzymes for the bacteria whilst bacteriostatic antibiotics don’t kill the bacteria, but simply inhibit bacterial reproduction, which is usually done through the disruption of protein synthesis.

Broad-spectrum antibiotics are a type of antibiotic which are effective against a wide range of bacteria or bacterial infections, whilst narrow-spectrum antibiotics are only effective against specific types of bacteria. Examples of broad-spectrum antibiotics include amoxicillin and doxycycline. Examples of narrow-spectrum antibiotics include vancomycin and the macrolides.

Why is it difficult to produce effective antiviral drugs?

Viral replication occurs by viruses entering a host cell, and the viral DNA or RNA inducing the cell to produce new virus particles. Due to the nature of viral replication, this makes it difficult to find drugs that will treat viral infections, and as the host cell produces the new virus particles, any drug that interferes with viral replication is highly likely to be toxic to the host

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