Potassium Phenoxymethyl Penicillin
Indications And Clinical Uses: Mild to moderately severe infections caused by penicillin V sensitive microorganisms including streptococcal pharyngitis, staphylococcal infection without bacteremia and pneumococcal infections. Therapy should be guided by bacteriologic sensitivity tests and clinical response.
Severe pneumonia, empyema, bacteremia, pericarditis, meningitis, and arthritis should not be treated with potassium phenoxymethyl penicillin during the acute stage.
Indicated surgical procedures should be performed.
The following infections will usually respond to adequate dosage of potassium phenoxymethyl penicillin:
Streptococcal infections (without bacteremia): Mild to moderate infections of the upper respiratory tract, scarlet fever, and mild erysipelas.
Note: Streptococci in groups A, C, G, H, L, and M are very sensitive to penicillin. Other groups, including group D (enterococcus), are resistant.
Pneumococcal infections: Mild to moderately severe infections of the respiratory tract.
Staphylococcal infections sensitive to penicillin V: Mild infections of the skin and soft tissues.
Note: Reports indicate an increasing number of strains of staphylococci resistant to penicillin V, which emphasizes the need for culture and sensitivity studies in treating suspected staphylococcal infections.
Fusospirochetosis (Vincent’s Gingivitis and Pharyngitis): Mild to moderately severe infections of the oropharynx usually respond to therapy with oral penicillin.
Note: Necessary dental care should be accomplished in infections involving the gum tissue.
For prophylaxis following rheumatic fever and/or chorea. (Prophylaxis with oral penicillin on a continuing basis has proved effective in preventing recurrences of these conditions.)
Although no controlled clinical efficacy studies have been conducted, penicillin V has been suggested by the American Heart Association and the American Dental Association for use as an oral regimen for prophylaxis against bacterial endocarditis in patients with congenital heart disease or rheumatic or other acquired valvular heart disease when they undergo dental procedures and surgical procedures of the respiratory tract. Since alpha-hemolytic streptococci relatively resistant to penicillin may be found when patients are receiving continuous oral penicillin for secondary prevention of rheumatic fever, prophylactic agents other than penicillin may be chosen for these patients and prescribed in addition to their continuous prophylactic regimen for rheumatic fever. Oral penicillin should not be used as adjunctive prophylaxis for genitourinary instrumentation or surgery, lower intestinal tract surgery, sigmoidoscopy, and childbirth. Note: When selecting antibiotics for the prevention of bacterial endocarditis, the physician or dentist should read the full joint statement of the American Heart Association and the American Dental Association.
Contra-Indications: A previous hypersensitivity reaction to any penicillin.
Precautions: Serious and occasionally fatal hypersensitivity (anaphylactoid) reactions have been reported in patients receiving penicillin therapy. Although anaphylaxis is more frequent following parenteral therapy, it has occurred with oral penicillins. These reactions are more apt to occur in individuals with a history of sensitivity to multiple allergens.
Careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins and other allergens. Cross-sensitivity between penicillin and cephalosporins is well documented. If an allergic reaction occurs, the drug should be discontinued and the patient treated with the usual agents (e.g., epinephrine or other pressor amines, antihistamines, or corticosteroids).
Penicillin should be used with caution in individuals with histories of allergies and/or asthma.
Oral administration should not be relied on in patients with severe illness, with nausea, vomiting, gastric dilatation, cardiospasm, or intestinal hypermotility.
Occasional patients will not absorb therapeutic amounts of oral penicillin.
In streptococcal infections, therapy should be given for 10 days minimum. Cultures should be taken following treatment to assure eradication of streptococci.
Prolonged use of antibiotics may promote overgrowth of non susceptible organisms, including fungi. Should superinfection occur, take appropriate measures.
Adverse Reactions: Although the incidence of reactions to oral penicillins is much lower than to parenteral therapy, all degrees of hypersensitivity including fatal anaphylaxis have been reported.
The most common reactions to oral penicillin are nausea, vomiting, epigastric distress, diarrhea, and black hairy tongue. The hypersensitivity reactions are skin eruptions (maculopapular to exfoliative dermatitis), urticaria; reactions resembling serum sickness, including chills, fever, edema, arthralgia and prostration; laryngeal edema; and anaphylaxis. Fever and eosinophilia may frequently be the only reactions observed. Hemolytic anemia, leukopenia, thrombocytopenia, neuropathy, and nephropathy may occur but are usually associated with high doses of parenteral penicillin. Although CNS toxicity has been reported with large doses of parenteral penicillin, it is unlikely, but remotely possible, that this could occur with oral therapy.
Symptoms And Treatment Of Overdose: Symptoms: Symptoms of large oral overdose of penicillin may cause nausea, vomiting, stomach pain, diarrhea and, in rare cases, major motor seizures. If other symptoms are present, consideration must also be given to the possibility of an allergic reaction or symptoms secondary to a concurrent medication or other underlying disease state, especially in adults. Hyperkalemia may result from overdosage, particularly in patients with renal insufficiency. tag_Treatment
Treatment: In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in your patient. Ensure adequate ventilation and protect the patient’s airway while attempting to limit drug absorption. In oral overdosage, consideration must be given to emesis or lavage to evacuate the stomach, and administration of activated charcoal by mouth or via lavage tube with a cathartic such as sorbitol may hasten drug elimination. Penicillin may be removed by hemodialysis. No specific antidote is known to be effective.
Dosage And Administration: The dosage should be determined according to the sensitivity of the microorganisms, the severity of infection and the clinical response.
The usual dosage recommendations for adults and children 12 years and over are:
- Streptococcal infections: Mild to moderately severe infections of the upper respiratory tract, including scarlet fever and mild erysipelas: 125 mg to 250 mg every 6 to 8 hours for 10 days;
- Pneumococcal infections: Mild to moderately severe infections of the respiratory tract, including otitis media: 250 mg 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 sensitivity tests should be performed): 250 mg every 6 to 8 hours;
- Fusospirochetosis (Vincent’s Infection) of the oropharynx: Mild to moderately severe infections: 250 mg every 6 to 8 hours.
Prophylaxis in the following conditions: To prevent recurrence following rheumatic fever and/or chorea: 250 mg twice daily on a continuing basis.
For prophylaxis against bacterial endocarditis in 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) i.v. or i.m. 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), i.m. or i.v. 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 eight hours later.
Children: Children’s antibiotics dosages should not exceed the maximum adult doses. For children under 12 years of age, dosage is calculated on the basis of body weight. Infants and small children: 15 to 50 mg/kg in 3 to 6 divided doses.
Availability And Storage: Each tablet contains: penicillin V potassium USP 250 mg (400 000 units). Sodium- and tartrazine-free. Bottles of 100. Identi-Code: C 29.
V-CILLIN K® Lilly Potassium Phenoxymethyl Penicillin Antibiotic