Prophylactic Antibiotic Premedication

Definition

Prophylactic antibiotic premedication is the practice of prescribing limited antibiotic therapy to dental patients who are at risk of contracting microbial disease as a result of invasive dental procedures.

Purpose

Oral bacteria can enter the bloodstream during dental procedures and are normally destroyed by the body's immune system. In certain cases, however, bacteria may settle on abnormal heart valves or tissue that has been weakened by surgery or an existing heart problem. Infective endocarditis, an infection of the endocardium or heart valves, can be the result. Prophylactic premedication with approved antibiotics manages and reduces the risk of infection.

A study published in November 2000 called into question whether antibiotic prophylaxis is necessary for dental treatment. Such treatment, the study concluded, does not seem to be a risk factor for infective endocarditis. The American Dental Association (ADA) and American Heart Association have stated that their current recommendations are valid, although further research is warranted. The ADA's Council on Scientific Affairs continues to monitor, analyze, and assess research in prophylactic premedication with antibiotics.

The use of prophylactic premedication in oral health care has undergone many changes since its inception. Dosages have been decreased, and the conditions requiring premedication have changed. Premedication for patients who are recipients of large joint prostheses is no longer universally recommended. Some associations of orthopedists, for instance, state that routine antibiotic coverage is not necessary for patients who have joint prostheses and are undergoing dental procedures. It is recognized, however, that decisions regarding premedication should be made on an individual basis.

Precautions

According to the American Heart Association, endocarditis rarely occurs in people with normal hearts. Certain preexisting heart conditions are susceptible to bacteremia, however. These include:

• an artificial (prosthetic) heart valve
• a history of previous endocarditis
• heart valves damaged (scarred) by conditions such as rheumatic fever
• congenital heart or heart valve defects
• mitral valve prolapse with a murmur
• hypertrophic cardiomyopathy

Description

Procedures affected

Dental procedures for which antibiotic premedication is indicated include those in which bleeding is likely. They include:

• dental extractions
• periodontal procedures, including surgery, scaling and root planing, probing, and periodontal maintenance
• dental implant placement and reimplantation of avulsed (torn-out) teeth
• endodontic (root canal) instrumentation or surgery—only beyond the apex
• subgingival placement of antibiotic strips
• initial placement of orthodontic fibers
• intraligamentary local anesthetic injections
• prophylactic cleaning of teeth or implants where bleeding is anticipated
• restorative dentistry with or without retraction cord
• local anesthetic injections
• intracanal endodontic treatment, post-placement and buildup
• placement of rubber dams
• postoperative suture removal
• placement of removable prosthodontic/orthodontic appliances
• taking of oral impressions, fluoride treatments
• taking of oral radiographs, orthodontic appliance adjustment
• shedding of primary teeth

Dosages recommended

The American Heart Association recommends the following standard regimens for dental treatment in patients at risk of bacterial endocarditis.

• General adult patients: 2 grams amoxicillin (children, 50 mg/kg) given orally one hour before procedure.
• Adult patients unable to take oral medications: 2 grams ampicillin (children, 50 mg/kg) given intramuscularly or intravenously within 30 minutes before procedure.
• Adult patients allergic to amoxicillin, ampicillin, or penicillin: 600 mg clindamycin (children, 20 mg/kg) given orally one hour before procedure. Alternatively, use 2 grams cephalexin or cefadroxil (children, 50 mg/kg) given orally one hour before procedure. Cephalosporins should not be used in patients with immediate-type hypersensitivity reaction to penicillins. Another alternative is 500 mg azithromycin or clarithromycin (children, 14 mg/kg) given orally one hour before procedure.
• Adult patients allergic to amoxicillin, ampicillin, or penicillin who are unable to take oral medications: 600 mg clindamycin (children, 20 mg/kg) intravenously within 30 minutes before procedure. Alternatively, use 1 gram cefazolin (children, 25 mg/kg) intramuscularly or intravenously within 30 minutes before procedure.

Preparation

Antibiotic premedication is given to the patient either one hour (oral) or 30 minutes (intramuscular and intravenous) prior to the procedure.

Complications

When prophylactic premedication is prescribed for dental treatment, prior use of antibiotics should be considered. Resistant organisms may develop, especially if the proposed dental treatment closely follows prior antibiotic exposure. In that case, it is recommended that dentists consult with the patient's physician on the drug chosen and its dosage.

Possible allergic reactions to antibiotics must also be considered. Careful attention to the patient's health history is indicated to determine any prior allergy.

Patients who have difficulty swallowing may be given antibiotics intravenously or intramuscularly.

Results

Prophylactic antibiotic premedication manages and reduces the risk of infective endocarditis as a result of dental treatment.

Health care team roles

Dentists prescribing prophylactic antibiotic premedication should consult with the patient's physicians, both general and specialty. When treating a patient with heart problems, for instance, the dentist would contact the patient's cardiologist. In determining whether a patient with a large joint prosthesis should be premedicated, the dentist should confer with the patient's orthopedic specialist.

Every member of the dental team must be aware of the risks of infective endocarditis to their patients. Health questionnaires should be scrutinized at the initial visit to identify patients at risk. On follow-up visits, health histories should be updated.

KEY TERMS

Bacteremia— Presence of bacteria in the blood.

Cardiomyopathy— Chronic disorder of the heart muscle that may involve hypertrophy and obstructive damage to the heart.

Endocardium— Membrane lining the chambers of the heart and covering the cusps of the various valves.

Infective endocarditis— A systemic disease characterized by focal bacterial infection of the heart valves, with formation of bacteria-laden vegetation.

Mitral valve prolapse— Downward displacement of the valve between the left atrium and ventricle of the heart.

Resources

PERIODICALS

Epstein, Joel B., D.M.D., M.S.D., F.R.C.D.(C); Sandra Chong, D.D.S.; Nhu D. Le, Ph.D. "A Survey of Antibiotic Use in Dentistry." Journal of the American Dental Association (November 2000): 1600.

Tong, Darryl C., B.D.S., M.S.D.; and Bruce R. Rothwell, D.M.D., M.S.D. "Antibiotic Prophylaxis in Dentistry: A Review and Practice Recommendations." Journal of the American Dental Association (March 2000): 366.

ORGANIZATIONS

American Dental Association. 211 East Chicago Ave., Chicago, IL 60611. (312) 440-2500. 〈http://www.ada.org〉.

American Heart Association. 7272 Greenville Ave., Dallas, TX 75231. (800) 242-8721. 〈http://www.americanheart.org〉.

OTHER

Author unspecified. "ADA Statement on Antibiotic Prophylaxis." American Dental Association website. 〈http://www.ada.org/prof/prac/issues/statements/endoprop.html〉 (March 26, 2001).

Author unspecified. "Antibiotic Prophylaxis for Dental Procedures." University of Manitoba website. 〈http://www.umanitoba.ca/cgi-bin/colleges/cps/college.cgi/342.html〉.

Author unspecified. "Bacterial Endocarditis." American Heart Association website 〈http://www.americanheart.org/Heart_and_Stroke_A_Z_Guide/bend.html〉.

Author unspecified. "Your Oral Health and Overall Health." American Dental Association website. 〈http://www.ada.org/public/faq/health.html〉 (September 12, 2000).