Pharmacology: Mechanism of Action: Flucloxacillin (Stafloxin) is a semi-synthetic isoxazolyl penicillin which is stable in the presence of gastric acid and penicillinase. By inhibiting the biosynthesis of the bacterial cell wall, it exerts a bactericidal action against penicillin-susceptible organisms during their active phase of multiplication.
Flucloxacillin (Stafloxin) is highly resistant to inactivation by staphylococcal penicillinase and is most active against both penicillinase-producing and non-penicillinase-producing strains of Staphylococcus aureus. It also has favorable activity against other Gram-positive bacteria such as Streptococcus pyogenes, Diplococcus pneumoniae, Group A beta hemolytic streptococci, and Streptococcus pneumoniae, but not against Streptococcus faecalis.
The therapeutic activity of Flucloxacillin (Stafloxin) is enhanced by combination with semi-synthetic penicillins such as ampicillin or amoxicillin.
Pharmacokinetics: Bioavailability/Bioequivalence Data: Flucloxacillin (Stafloxin) is rapidly absorbed after an intramuscular dose and reaches serum levels nearly twice that of an equivalent oral dose, 30 minutes after an injection.
Flucloxacillin is highly protein-bound but its tissue penetration is fairly good.
An intravenous dose of 500 mg can achieve a serum level of 44.3 ug/mL while a 2 g dose can achieve a serum level of 244 ug/mL after 15 minutes and 135 ug/mL after 30 minutes. A serum level of 17 ug/mL can be reached with a 500 mg I.M. dose.
The mean peak plasma levels reported for Flucloxacillin (Stafloxin) 250 mg and 500 mg oral doses are 6.9 ug/mL and 11-20 ug/mL, respectively, whereas for free drug is 0.6 ug.mL. After 6 hours, serum concentration falls to 0.46 ug/mL. The serum elimination half-life is 1.35 hours.
Absorption is 44 % after oral administration. Although Flucloxacillin is highly protein-bound (96 %), its tissue penetration is fairly good. It achieves relatively high levels in peripheral lymph and blister fluid as shown by studies by Bergan, et al. Flucloxacillin is excreted primarily in the urine in the active unchanged form (65 %). The metabolite, hydroxyflucloxacillin, is bactericidal and its half-life is twice that of Flucloxacillin. The renal and extra-renal elimination of Flucloxacillin is lower than that of cloxacillin, resulting in a greater area under the concentration curve. This gives Flucloxacillin an advantage over the other isoxazolyl penicillins.
STAFLOXIN is indicated for the treatment of infections such as pneumonia, septicemia, endocarditis, infected prosthesis, osteomyelitis, skin and soft tissue infections, infected burns, and infected joints due to benzylpenicillin-resistant staphylococci; for mixed streptococcal and staphylococcal infections where the staphylococci are penicillin-resistant, as in empyema and other respiratory tract infections; and for the initial treatment of suspected cases of resistant staphylococci infections, prior to the availability of test results.
(Note: Culture/Sensitivity tests should be performed initially to determine the causative organisms and their sensitivity. DO NOT use STAFLOXIN in infections caused by organisms susceptible to Penicillin G.).
Dosage: (Every 6 hours): Intravenous and Intramuscular: Adults & Older Children: 250 to 500 mg depending upon the severity of infection, or as prescribed.
Children: From birth to 6 months: 25 mg/KBW/day in divided doses.
6 months to 2 years: 25 to 50 mg/KBW/day in divided doses.
2 to 10 years: 125 to 250 mg.
Doses may be doubled in severe infections.
Dosage: (Recommended duration of therapy: 7-10 days): STAFLOXIN 250 mg CAPSULE: Adults and Older Children: 1 to 2 capsules every 6 hours depending upon the severity of infection.
Should be taken one hour before meals.
STAFLOXIN 500 mg CAPSULE: Adults and Older Children: 1 capsule every 6 hours or as prescribed.
Should be taken one hour before meals.
In severe infections, dosage may be doubled or administer STAFLOXIN INJECTABLE intramuscularly or intravenously.
Flucloxacillin is contraindicated in patients known to be sensitive to penicillins.
It should be given with caution to patients with known history of allergy. Use with caution in jaundiced neonates.
A report of cholestatic jaundice suggests allergic etiology. Give with caution to patients with hepatic disorder. There is a risk of developing cholestatic jaundice with prolonged therapy (> 14 days) and in elderly (50 years old) patients.
Like any other penicillin, Flucloxacillin may cause anaphylactic reaction; therefore, adequate testing and precaution for sensitivity should be done prior to use.
For intramuscular injections, care should be taken to avoid sciatic nerve injury.
With intravenous administration, particularly in elderly individuals, care should be taken because of the possibility of thrombophlebitis.
Occasional reports of nausea, diarrhea, flatulence, and headache.
Adverse reactions are essentially limited to sensitivity phenomena. They are more likely to occur in individuals with previously demonstrated hypersensitivity and in those with known history of allergy, asthma, hay fever, or urticaria.
Transient symptomatic and asymptomatic elevations of SGOT, SGPT, and LDH have been noted in patients receiving semi-synthetic penicillins (particularly oxacillin). Such reactions are more common in infants. There have been occasional reports of cholestatic jaundice which is reversible upon discontinuation of drug usage.
There have been transient hematuria, proteinuria and azotemia in newborns and infants receiving high doses (150-175 mg/KBW/day).
Concurrent administration of bacteriostatic antibiotics such as tetracyclin and erythromycin may diminish the bactericidal effects of Flucloxacillin by slowing down the rate of bacterial growth.
Flucloxacillin is incompatible when mixed or given together with Colistin sulphomethate sodium, gentamicin, kanamycin and Polymyxin B sulphate. Loss of potency after mixing with streptomycin has been reported. Combination of amoxicillin enhances its therapeutic activity.
J01CF05 - flucloxacillin ; Belongs to the class of beta-lactamase resistant penicillins. Used in the systemic treatment of infections.
Cap 250 mg x 50's. 500 mg x 50's. Susp 125 mg/5 mL x 60 mL. Vial 250 mg x 1's. 500 mg x 1's.