How It Works

Antibiotics kill bacteria.

Why It Is Used

Antibiotics may be used alone or in combinations to treat bacterial meningitis.

How Well It Works

Ampicillin and penicillin g are effective against many bacteria that cause meningitis, including Listeria monocytogenes, certain strains of Streptococcus pneumoniae, Neisseria meningitidis, and group B streptococcus.

Ceftriaxone and cefotaxime also are effective against many bacteria that cause meningitis, including most Streptococcus pneumoniae, Haemophilus influenzae type b, and Escherichia (E.) coli.

Gentamicin sulfate is effective against E. coli. It often is used with ampicillin to treat people who have bacterial meningitis caused by group B streptococci.

Ciprofloxacin and rifampin are often effective at preventing infection when they are given to people who have been exposed to meningitis. Rifampin is the preferred medication for children.

Vancomycin is effective against many bacteria that are not killed by other antibiotics.

Side Effects

The most common side effects of antibiotics include:

• Nausea and vomiting.
• Diarrhea.
• Allergic reactions including skin rash, fever, and sometimes difficulty breathing.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Antibiotics used to treat bacterial meningitis usually are given into a vein (intravenous, or IV), 1 to 4 times a day. The number of days the medication is given (between 7 and 21) depends on the bacteria causing the infection, the severity of the illness, the person's age, and whether the person is likely to develop severe meningitis or complications.

Penicillin and cefotaxime are two of the antibiotics most frequently used to treat meningitis. However, some bacteria (particularly Streptococcus pneumoniae) are becoming increasingly resistant to penicillin. As a result, doctors often combine different types of antibiotics to try to kill all bacteria. For infants older than 1 month, treatment may include vancomycin and cefotaxime or ceftriaxone. For infants younger than 1 month, vancomycin may be added to the usual treatment of ampicillin and cefotaxime or ceftriaxone.

Some people may be allergic to ampicillin and penicillin g.

People who receive gentamicin sulfate or vancomycin need to be checked for hearing problems, low back pain, or less-than-expected amounts of urine. These medications can cause hearing loss and kidney damage. Kidney damage usually clears up once the medications are stopped.

People should take antibiotics only when they have a bacterial infection. Antibiotics do not kill viruses and other organisms. Because of the problem of resistance, people who take antibiotics when they do not have a bacterial infection may require stronger antibiotics for future bacterial infections.