Wydox

Description

• Bactericidal and resistant to staphylococcal penicillinase.
• Active against most gram positive cocci including beta-hemolytic streptococci, pneumococci and nonpenicillinase producing staphylococci.
• It is also active against penicillinase producing staphylococci.

PHARMACOKINETICS

ABSORPTION

• The intramuscular injection of 500 mg peak plasma concentrations of up to 15 µg per mL have been achieved after 30 minutes.
• Doubling the dose can double the plasma concentration.

DISTRIBUTION

• Plasma half-life of 0.5 to 1 hour. The half-life is prolonged in neonates.
• About 93% of the oxacillin in the circulation is bound to plasma proteins.
• Crosses the placenta and is excreted in breast milk.

METABOLISM

• Oxacillin undergoes some metabolism.

EXCRETION

• The unchanged drug and metabolites are excreted in the urine by glomerular filtration and renal tubular secretion.
• More than 40% of an intramuscular dose is rapidly excreted in the urine.
• Oxacillin is also excreted in the bile.

INDICATIONS

Oxacillin (Wydox®) is an isoxazolyl penicillin used primarily for the treatment of infections due to staphylococci resistant to benzylpenicillin. These include:

• Bone and joint infections

• Endocarditis
• Peritonitis (associated with continuous ambulatory peritoneal dialysis)
• Pneumonia
• Skin disorders (including soft-tissue infections)
• Surgical infection (prophylaxis)
• Toxic shock syndrome

DOSE

DOSAGE AND ADMINISTRATION

TREATMENT DOSAGE

1. For mild and moderate upper respiratory and localized skin and soft tissue infections

Age Group	Dose	Frequency
Adults & children weighing 40 kg or more Children weighing less than 40 kg	250 mg to 500 mg50mg/kg/day in equally divided doses	Every 4 to 6 hoursEvery 6 hours

2. For more severe infections, such as those of the lower respiratory tract or disseminated infections

Age Group	Dose	Frequency
Adults & children weighing 40 kg or more Children weighing less than 40 kg	1 g or higher100mg/kg/day or higher in equally divided doses	Every 4 to 6 hoursEvery 4 to 6 hours

PREPARATION AND ADMINISTRATION

INTRAMUSCULAR USE

• For 250 mg vial: add 1.4 mL of Sterile Water for Injection USP.
• For 500 mg vial: add 2.8 mL of Sterile Water for Injection USP.
• Shake well until a clear solution is obtained.
• After reconstitution, solution retains its potency for 3 days at 25°C for one week under refrigeration.

INTRAVENOUS USE

• Add 5 mL of Sterile Water for Injection USP or Sodium Chloride Injection USP to each 250 or 500 mg vial.
• The resulting solution should be administered slowly over a 10 minute period.

CONTRAINDICATIONS

• Contraindicated in those persons who have shown a hypersensitivity to the drug.

PRECAUTIONS

• WYDOX® should be given with caution to patients with a history of allergy, especially to drugs.
• Care is necessary if very high doses of WYDOX® are given, especially if renal function is poor.
• Renal and hematological status should be monitored during prolonged and high dose therapy.

USE IN PREGNANCY

• There are no controlled studies in pregnant women.

NURSING MOTHERS

• WYDOX® is excreted in human milk. Caution should be exercised if use is indicated.

DRUG INTERACTION

• WYDOX® may decrease the efficacy of estrogen-containing oral contraceptives.
• Certain antibiotics given by injection
• Probenecid
• Rifampin

ADVERSE EFFECTS

Most Common Adverse Effects:

• Hypersensitivity reactions, especially skin rashes

Other Adverse Effects:

• Anaphylaxis (occasionally occurs and has sometimes been fatal)
• Hemolytic anemia and neutropenia
• Prolongation of bleeding time and defective platelet function
• Convulsions and other signs of central nervous system toxicity.
• Jarisch-Herxheimer reaction (some patients with syphilis)

Symptoms include:

• Fever
• Chills
• Headache
• Reactions at the site of the lesions

◘ Hypersensitivity to Oxacillin sodium gives rise to a wide variety of clinical syndromes.

Immediate Reactions Include:

• Anaphylaxis
• Angioedema
• Urticaria
• Some maculopapular rashes

Late Reactions Include:

• Serum sickness-like reactions
• Hemolytic anemia
• Acute interstitial nephritis

STORAGE RECOMMENDATION

• Store at temperature not exceeding 30°C.

PHARMACEUTICAL INFORMATION

DRUG SUBSTANCE

Proper Name : Oxacillin Sodium

Chemical Name : C19H18N3NaO5S · H2O

Structural Formula :

Molecular Formula : 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, 3.3-dimethyl-6-[[(5-methyl-3-phenyl-4-isoxazolyl) carbonyl] amino]-7-oxo-,monosodium salt, monohydrate, [2S (2a, 5a, 6b)]-.

Molecular Weight : 441.3

Description : Fine, white, crystalline powder, odorless or having a slight odor. Freely soluble in water, in methanol, and in dimethyl sulfoxide; slightly soluble in absolute alcohol, in chloroform, in pyridine, and in methyl acetate; insoluble in ethyl acetate, in ether, in benzene, and in ethylene chloride.

DRUG PRODUCT

Oxacillin (as Sodium) 250 mg Powder for Injection I.M. / I.V. (Wydox)

BFAD Registration No.: DRP-480

Oxacillin (as Sodium) 500 mg Powder for Injection I.M. / I.V. (Wydox)

BFAD Registration No.: DRP-404

• Oxacillin Sodium (Wydox®) 250 mg and 500 mg Powder for Injection

Description:

1. Dry Product

a.1. Color : White crystalline powder

a.2. Odor : Odorless to practically so

1. Reconstituted Product

➟ Clear, colorless solution

AVAILABILITY

• WYDOX® is supplied in sterilized rubber-stoppered vials containing 250 mg and 500 mg. Box of 10 vials.

REFERENCES

• Reynolds, James EF, Martindale 31st edition, (London, 1996).
• The United States Pharmacopeia 27th ed. and The National Formulary 22nd ed. (Asian edition, 2004).
• www.DrugDigest.org.

FORMULATION:

ACTIVE INGREDIENTS

• Oxacillin sodium

INACTIVE INGREDIENT/ EXCIPIENTS

• No added excipients