You can relax about your family members. For certain people, it
is very important to take an antibiotic before dental treatment.
However, this is only necessary for a few people with specific
medical problems. Antibiotics are mainly used to treat an
infection that has already begun. That is, bacteria have
collected somewhere in the body and are already causing damage.
Antibiotics are taken to help the body fight off the bacteria.
For the examples in your letter, the idea is to take an
antibiotic to prevent a possible infection. This is called a
prophylactic antibiotic. Rather than the antibiotic being taken
for many days, a prophylactic antibiotic is usually taken only
once, about an hour before an appointment. The antibiotic
remains in the body for a few hours to kill bacteria from the
mouth that might enter the bloodstream during the dental
appointment. Under specific circumstances, prophylactic
antibiotics may be considered. Many people have heart murmurs.
These extra sounds are made by blood flowing throu