Antimicrobial Use Guidelines (AMUG) version 21 - UW Health

CommentsDose adjustment required for renal impairment. See renal dosing guideline on uconnect.For systemic infantile group B streptococcal infections and viridans streptococcal infections in immunocompromisedhosts, gentamicin should be added for synergy until the penicillin MIC is known. Low-level and occasional high-levelpenicillin-resistant Streptococcus pneumoniae have been reported from multiple geographic areas in the US, includingWisconsin. For serious Streptococcus pneumoniae infections (e.g., meningitis or life-threatening sepsis), ceftriaxone isrecommended in combination with vancomycin and sometimes rifampin until penicillin susceptibility is documented.Penicillin G potassium contains 1.7 mEq potassium per million units. Penicillin G sodium contains 2 mEq sodium permillion units. One million units of penicillin G equal 625 mg. Long-acting injectable penicillin is available on the UWHCformulary as penicillin G benzathine (Bicillin L-A ® ) and penicillin G benzathine/procaine (Bicillin C-R ® ). Usual adult dosesare 1,200,000 units via deep IM injection every 7-28 days.Drug Interactions• Aminoglycosides – inactivated by penicillins in admixtures when penicillin:AG ratio is 50:1 or higher• Oral contraceptives – decreased efficacy due alteration of intestinal flora and resultant reduction of enterohepaticcirculation of hormones• Live typhoid vaccine – decreased efficacy; wait 24 hours after end of therapy to give vaccine• Tetracyclines – bacteriostatic drugs may antagonize antibiotics such as penicillins, which work on actively growingbacteria• Methotrexate – penicillin has been reported to increase methotrexate toxicity in some cases, possibly by competingfor renal tubular secretionPENICILLIN VKUsual DoseAdult: 125-500 mg Q6-12H PO (UWHC cost/day $0.07-0.51). Note: Q12H dose is for outpatient setting only.Pediatric:** 25 - 50 mg/kg/day PO in divided doses Q6H.Indications1. Group A streptococcal pharyngitis – First-line therapy (Children: 250 mg BID-TID PO. Adolescents and adults: 500 mgBID-TID PO).2. Oral/dental infections.3. Rheumatic fever prophylaxis in children (250 mg BID PO).4. Pneumococcal infection prophylaxis in children with sickle cell anemia (children < 5 years 125 mg BID PO, children > 5years 250 mg BID PO).CommentsDose adjustment required for renal impairment. See renal dosing guideline on uconnect.Oral penicillin VK should not be used preferentially over IV penicillin for severe pneumonia, empyema, bacteremia,pericarditis, meningitis or arthritis. Beta-streptococci are still very susceptible to penicillin. Some viridans streptococci andenterococci may be resistant. Caution is warranted due to emergence of penicillin-resistant pneumococci. Penicillin VKcontains 2.6 mEq potassium per gram. One million units of penicillin G equal 625 mg.Drug Interactions• Aminoglycosides – inactivated by penicillins in admixtures when penicillin:AG ratio is 50:1 or higher• Oral contraceptives – decreased efficacy due alteration of intestinal flora and resultant reduction of enterohepaticcirculation of hormones• Live typhoid vaccine – decreased efficacy; wait 24 hours after end of therapy to give vaccine• Tetracyclines – bacteriostatic drugs may antagonize antibiotics such as penicillins, which work on actively growingbacteria• Guar gum – reduces oral penicillin’s bioavailability when taken at the same time• Methotrexate – penicillin has been reported to increase methotrexate toxicity in some cases, possibly by competingfor renal tubular secretion