If you've ever been given an antibiotic, such as penicillin, to treat an infection, then you've taken an anti-infective medication. This category of drugs includes antivirals and vaccines.
Antibiotics are used to treat a wide variety of bacterial infections. They inhibit the growth of bacteria by interfering with the production of certain biochemicals necessary to sustain the bacteria's life or by interfering with the bacteria's ability to use nutrients. The body's defenses then have a much easier time eliminating the infection.
When used properly, antibiotics are usually effective. To treat an infection adequately, however, antibiotics must be taken regularly for a specified time. If they are not taken for the prescribed period, microorganisms resistant to the antibiotic may continue growing, and the infection could recur. Aminoglycosides, cephalosporins, erythromycins, penicillins (including ampicillin and amoxicillin), quinolones, and tetracyclines are some examples of antibiotics.
Antibiotics do not counteract viruses, including those that cause the common cold, so their use in cold therapy is inappropriate.
Antiviral medications are used to combat viral infections. An antiviral drug called acyclovir is being used in the management of herpes infection. This medication reduces the reproduction of the herpes virus in initial outbreaks, lessens the number of outbreaks of recurrent infection, and speeds the healing of herpes blisters. Acyclovir does not cure the disease, however.
Vaccines were used long before antibiotics became available. A vaccine contains weakened or dead disease-causing microorganisms or parts of such organisms, which activate the body's immune system to produce a natural defense against a particular disease (such as polio or measles). A vaccine is usually given to prevent a specific disease, but it may also be used in certain circumstances to alleviate or treat an infectious disease that has already taken hold.
Drugs called anthelmintics are used to treat worm infestations. Fungal infections are treated with antifungals, such as nystatin, that destroy and prevent the growth of fungi. A pediculicide is a drug used to treat a person infested with lice. And a scabicide is prescribed to deal with scabies.