The dosage of penicillin V potassium should be determined according to the susceptibility of the causative microorganism and the severity of infection and should be adjusted to the clinical response of the patient.
The usual dosage recommendations for adults and children 12 years and over are as follows:
Streptococcal Infections: Mild to moderately severe infections of the upper respiratory tract, including scarlet fever and mild erysipelas: 200,000 to 500,000 units every 6 to 8 hours for 10 days.
Pneumococcal Infections: Mild to moderately severe infections of the respiratory tract, including otitis media: 400,000 to 500,000 units every 6 hours until the patient has been afebrile for at least 2 days.
Staphylococcal Infections: Mild infections of skin and soft tissue (culture and susceptibility tests should be performed): 400,000 to 500,000 units every 6 to 8 hours.
Fusospirochetosis (Vincent's Infection) of the Oropharynx: Mild to moderately severe infections: 400,000 to 500,000 units every 6 to 8 hours.
Prophylaxis in the Following Conditions: To prevent recurrence following rheumatic fever and/or chorea: 200,000 to 250,000 units twice daily on a continuing basis.
For prophylaxis against bacterial endocarditis1in patients with congenital heart disease or rheumatic or other acquired valvular heart disease when undergoing dental procedures or surgical procedures of the upper respiratory tract, 1 of 2 regimens may be selected:
(1) For the oral regimen, the usual adult dosage is 2 g of penicillin V (1 g for children less than 30 kg) 1 hour before the procedure and then 1 g (500 mg for children less than 30 kg) 6 hours later.
(2) For patients unable to take oral antibiotics, 2,000,000 units of aqueous penicillin G (50,000 units/kg for children) IV or IM may be substituted 30 to 60 minutes before the procedure and 1,000,000 units (25,000 units/kg for children) 6 hours later.
For patients with prosthetic valves and for those at highest risk for endocarditis, ampicillin, 1 to 2 g (50 mg/kg for children), plus gentamicin, 1.5 mg/kg (2 mg/kg for children), IM or IV, may be given one- half hour prior to the procedure, followed by 1 g of oral penicillin V 6 hours later. Alternatively, the parenteral regimen should be repeated once every 8 hours later.
Children's antibiotic dosages should not exceed the maximum adult doses.
NOTE: Therapy for children under 12 years of age is calculated on the basis of body weight. For infants and small children, the suggested daily dose is 25,000 to 90,000 units (15 to 50 mg)/kg in 3 to 6 divided doses.
After being mixed, the solution should be stored in a refrigerator. It may be kept for 14 days without significant loss of potency. Shake well before using. Keep tightly closed.
Tablets should be stored at controlled room temperature, 59° to 86°F (15° to 30°C).
REFERENCES
1. Dajani AS, Bisno AL, et al: Prevention of bacterial endocarditis. Recommendations by the American Heart Association.JAMA, 1990;264:2919.
Last updated on RxList: 12/8/2004