Penicillin VK

Penicillin VK is a beta-lactam antibiotic and is bactericidal against gram-positive cocci and the major microbes of mixed anaerobic infections. Adverse drug reactions include mild diarrhea, nausea and oral candidiasis. There is a 0.7 to 10% allergy rate among patients. About 85% of allergic reactions are delayed and take greater than 2 days to develop. The usual allergic responses exhibited are skin rashes that usually respond to antihistamine therapy (diphenhydramine, Benadryl®). Severe reactions of angioedema have occurred, characterized by severe swelling of the lips, tongue, face, and periorbital tissues. Patients reporting a history of penicillin allergy should never be given Penicillin VK. The alternative antibiotic is clindamycin. If the allergy reaction is of the delayed type and not anaphylactoid, a first-generation cephalosporin may used as an alternative.

Penicillin VK may be given with meals, however blood concentrations are slightly higher when given on an empty stomach. The preferred dosing is one hour before meals or two hours after meals.

Contraindications: Hypersensitivity to penicillin or any component of the formulation.

Warnings/Precautions: Use with caution in patients with severe renal impairment (modify dosage), history of seizures, hypersensitivity to cephalosporins.

The usual daily dose of penicillin VK for treating odontogenic infections is:

Children ≤ 12 years of age: 25-50 mg/kg of body weight in divided does every 6-8 hours.
Children > 12 years of age and adults: 250-500 mg every 6 hours for at least 10 days.
Penicillin VK is supplied as 125 or 250 mg/5 ml solution or 250 and 500 mg tablets.

Sample penicillin VK prescription for a 3-year-old patient weighing 12 kg (25 lb) with facial swelling:

Rx: Penicillin VK 125 mg/5 ml
Disp: 200 ml
Sig: Take 1 teaspoon every 6 hours for 10 days