Therapeutic considerations in special patients.

Careful attention to patients' histories and their medical problems and consultation with their physicians should provide sound bases for selection of drugs. Antibiotic prophylaxis for patients with cardiovascular disorders is described for American Heart Association standards, but for other indications sound judgment based on the principles of antibiotic prophylaxis must be the rule. Patients with end-stage renal disease and severe liver impairment may be at risk with certain drugs. The most critical time for consideration of use of drugs during pregnancy is the first trimester. However, careful selection of drugs for use during the balance of the term can reduce the risk of harm to the mother and fetus.