Oxacillin dosing

Penicillin C 24 million units/24 hours IV in 4 to 6 equally divided doses may be used in place of nafcillin or oxacillin if strain is penicillin-susceptible (minimum inhibitory concentration less than or equal to 0.1 mcg/mL) and does not produce P-lactamase. cGentamicin should be administered in close temporal proximity to vancomycin, nafcillin, or oxacillin dosing. 

Gentamicin should be administered in close proximity to vancomycin, nafcillin, or oxacillin dosing. cPediatric dose should not exceed that of a normal adult. 

Therefore 2.5 mL contains the desired dose of 125 mg of oxacillin oral suspension. 

Nafci 11 i n/oxaci 11 f n 75 mg/kg IV per day in divided doses every 8-12 hours Nafcillin 100-150 mg/kg IV per day in divided doses every 6-8 hours Oxacillin 150-200 mg/kg IV per day in divided doses every 6-8 hours 200 mg/kg IV per day in divided doses every 6 hours max, 2 gm pediatrics greater than 3 months of age... 

Nafcillin or oxacillin 12 g/24 hours IV in 4-6 equally divided doses 6 IA For complicated right-sided IE and for left-sided IE, 6-week treatment for uncomplicated rightsided IE, 2-week treatment... 

For penicillin-allergic (nonanaphylactoid type) patients cefazolin 6 g/24 hours IV in 3 equally divided doses 6 IB Consider skin testing for oxacillin-susceptible staphylococci and questionable history of immediate-type hypersensitivity to penicillin cephalosporins should be avoided in patients with anaphylactoid-type hypersensitivity to P-lactams vancomycin should be used in these cases ... 

Oxacillin-resistant strains Vancomycin6 doses Pediatic dose cefazolin 100 mg/kg per 24 hours IV in three equally divided doses gentamicin 3 mg/kg per 24 hours IV/ IM in three equally divided doses 30 mg/kg per 24 hours IV in two equally divided doses 6 weeks IB Adjust vancomycin dosage to achieve 1 -hour serum concentration of... 

Nafcillin or oxacillin plus 12 g/24 hours IV in four to six equally divided doses >6 1 B... 

As streptococcal cellulitis is indistinguishable clinically from staphylococcal cellulitis, administration of a semisynthetic penicillin (nafrillin or oxacillin) or first-generation cephalosporin (cefazolin) is recommended until a definitive diagnosis, by skin or blood cultures, can be made (Table 47-4). If documented to be a mild cellulitis secondary to streptococci, oral penicillin VK, or intramuscular procaine penicillin may be administered. More severe streptococcal infections should be treated with IV antibiotics (such as ceftriaxone 50 to 100 mg/kg as a single dose). 

For parenteral therapy, nafciUin and oxacillin offer comparable efficacy and antimicrobial spectra of activity. Although both drugs undergo hepatic metabolism, only nafcillin requires dose adjustment in patients with combined hepatic and renal insufficiency. Other pharmacokinetic data for nafcillin and oxacillin appear in Table 45.1. Indications for nafcillin or oxacillin include severe staphylococcal infections like cellulitis, empyema, endocarditis, osteomyelitis, pneumonia, septic arthritis, and toxic shock syndrome. 

Nafcillin is primarily cleared by biliary excretion. Oxacillin, dicloxacillin, and cloxacillin are eliminated by both the kidney and biliary excretion no dosage adjustment is required for these drugs in renal failure. Because clearance of penicillins is less efficient in the newborn, doses adjusted for weight alone result in higher systemic concentrations for longer periods than in the adult. 

In one series, 22 of 128 patients receiving cloxacillin for staphylococcal infections became neutropenic (67). Neutropenia appeared, on average, 23 days after the start of therapy. The same authors, in a somewhat bigger population, found neutropenia in 1.1% of patients who received cumulative doses of oxacillin below 150 g, but in 43% (22 of 51) who received more than 150 g (5). Similarly, in 132 patients, cefapirin in a cumulative dose of less than 90 g did not cause neutropenia, but did in 26% (five of 19) of those who used higher total doses (21). 

One type of hepatitis is mainly associated with oxaciUin (178,179). Eight of 54 patients developed this reaction after a mean cumulative dose of oxacillin 157 g (180). 

Onorato IM, Axelrod JL. Hepatitis from intravenous high-dose oxacillin therapy findings in an adult inpatient population. Ann Intern Med 1978 89(4) 497-500. 

The other isoxazolyl penicillins, that is cloxacUUn, dicloxacilUn, and oxacillin, can cause similar hepatotoxicity (77-82). However, it is not known whether the incidence is as high as with flucloxaciUin. Nor is it known whether the clearly dose-dependent oxacillin hepatitis (83-85) is an identical reaction. 

Michelson PA. Reversible high dose oxacillin-associated liver injury. Can J Hosp Pharm 1981 34 83. 

Most are eliminated via active tubular secretion with half-life <60 min. Dose reduction needed only in major renal dysfunction. Nafcillin and oxacillin eliminated largely in bile ampicillin undergoes enterohepatic cycling, but is excreted by the kidney. Benzathine penicillin G—repository form (half-life of 2 weeks). 

Oxacillin is absorbed rapidly, but incompletely from the G1 tract it is stable in an acid environment. Peak serum concentrations occur within 1/2 to 2 hours after an oral dose and 30 minutes after an IM dose. Food decreases absorption. 

In healthy subjects, sulfamethoxypyridazine 3 g given 8 hours before a 1-g dose of oral oxacillin reduced the 6-hour urinary recovery by 55%. Sulfaethidole 3.9 g given 3 hours before the oxacillin reduced the 6-hour... 

Titier K, Lagrange F, Pehourcq E, Moore N, Molimard M. Pharmacokinetic interaction between high-dose methotrexate and oxacillin. Then Drug Monit (2002) 24, 570-2. 

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