Antimicrobials are substances that kills microorganisms or stop them from growing and causing disease. Antimicrobials are grouped according to the type of organism it acts against; antibacterials against bacteria, antivirals against viruses, antifungals and antiparasitics against fungi and parasites.
Antibacterial drugs are derived from bacteria or molds or are synthesized from scratch in a lab. Technically, “antibiotic” refers only to antimicrobials derived from bacteria or molds but is often used synonymously with “antibacterial drug.”
Antibiotics have many mechanisms of action, including the following:
Antibiotics sometimes interact with other drugs, raising or lowering serum levels of other drugs by increasing or decreasing their metabolism or by various other mechanisms. The most clinically important interactions involve drugs with a low therapeutic ratio (ie, toxic levels are close to therapeutic levels). Also, other drugs can increase or decrease levels of antibiotics.
Many antibiotics are chemically related and are thus grouped into classes. Although drugs within each class share structural and functional similarities, they often have different pharmacology and spectra of activity.
Antiviral drugs are used to treat viral infections. Most antivirals target a specific virus (e.g. Tamiflu targets the Influenza virus), though there are some broad-spectrum antivirals on the market. Most antiviral agents are only effective while the virus is replicating. There are also preventative antiviral drugs that protect you from getting and/or spreading a virus; the most common of which are vaccines.
Antivirals can work in any of three ways:
Antifungal (antimycotic) drugs treat fungal infections by either killing the fungus or stopping its growth. Many antifungal treatments for common fungal infections (eg. Athlete's Foot), are available over-the-counter. However, for more complex fungal infections a prescription antifungal is necessary. Antifungals can be administered topically (creams or ointments that go directly on the skin infection), orally, or intravenously.
There are three classes of antifungal treatments:
Antiparasitic drugs are a group of medications used in the management and treatment of infections by parasites. Antiparasitic drugs are classed by the type of organism they act against.