Sunday, July 26, 2009

Vancomycin

Pronunciation: (van-koe-MY-sin)

Class: Anti-infective agent

Trade Names:

Lyphocin
- Powder for injection, lyophilized 500 mg
- Powder for injection, lyophilized 1 g
- Powder for injection, lyophilized 5 g
- Powder for injection, lyophilized 10 g

Trade Names:

Vancocin
- Pulvules 125 mg
- Pulvules 250 mg
- Powder for injection 500 mg
- Powder for injection 10 g

Trade Names:

Vancoled
- Powder for injection 500 mg
- Powder for injection 1 g
- Powder for injection 5 g

Trade Names:

Vancomycin Hydrochloride
- Powder for oral solution 1 g

Pharmacology

Inhibits bacterial cell wall synthesis and alters cell-membrane permeability and RNA synthesis.

Pharmacokinetics

Absorption

Poorly absorbed (orally). C max is 63 mcg/mL. T max is 1 h.

Distribution

55% protein bound. Vd is 0.3 to 0.43 L/kg. Distributes to pleural, pericardial, ascitic, and synovial fluids; in urine; in peritoneal dialysis fluid; and atrial appendage tissue.

Metabolism

No apparent metabolism of the drug.

Elimination

Mean t ½ is 4 to 6 h. 75% is excreted in urine by glomerular filtration (in the first 24 h). Mean plasma Cl is 0.058 L/kg/h. Renal Cl is 0.048 L/kg/h.

Special Populations

Renal Function Impairment

Renal function impairment slows excretion of vancomycin in anephric patients, t ½ is 7.5 days.

Elderly

Total systemic and renal Cl may be reduced.

Indications and Usage

Parenteral

Treatment of serious or severe infections due to susceptible bacteria not treatable with other antimicrobials (eg, staphylococcus).

Oral

Treatment of pseudomembranous colitis caused by Clostridium difficile ; treatment of staphylococcal enterocolitis.

Unlabeled Uses

IV prophylaxis against bacterial endocarditis in penicillin-allergic patients.

Contraindications

Standard considerations.

Dosage and Administration

Adults

PO 500 mg to 2 g/day in 3 or 4 divided doses for 7 to 10 days.

Children

PO 40 mg/kg/day (up to 2 g/day) in 3 or 4 divided doses for 7 to 10 days.

Newborns

PO 10 mg/kg/day in divided doses.

Adults

IV 500 mg by IV infusion every 6 h or 1 g every 12 h.

Children

IV 10 mg/kg/dose every 6 h.

Infants & Newborns

IV 15 mg/kg initially, followed by 10 mg/kg every 12 h for newborns in first week of life, and every 8 h for ages up to 1 mo.

General Advice

* Prepare oral solution by adding 115 mL of water to 10 g vial or 20 mL of water to 1 g vial. Further dilute prepared oral solution dose with 30 mL of water or flavoring syrups may be used with oral solution.
* May give oral solution via nasogastric tube as indicated or ordered.
* Reconstitute parenteral form with sterile water for injection.
* Further dilute parenteral medication with compatible solution (eg, dextrose injection 5%, sodium chloride 0.9%, lactated Ringer's).
* Parenteral form may be administered by oral route.
* Reconstituted oral solution may be stored in refrigerator for 2 wk after bottle is opened.
* Dilute to minimum dilution of 2.5 mL and infuse parenteral solution over at least 60 min. Intermittent infusion preferred.
* Pretreat with antihistamine if patient has previously experienced Red Man Syndrome.
* Dosage or dosage interval may be changed based upon vancomycin serum levels.
* Reconstituted powder for injection is stable at room temperature for 2 wk.
* Dilute solutions (sodium chloride or D5W) are stable at room temperature for 24 h.

Drug Interactions



Aminoglycosides increased risk of nephrotoxicity and ototoxicity when vancomycin given with aminoglycosides
Amphotericin possible increased risk of nephrotoxicity when vancomycin given with amphotericin Close monitoring required with concomitant administration of nephrotoxic drugs or cytotoxics
Anaesthetics, General hypersensitivity-like reactions can occur when intravenous vancomycin given with general anaesthetics See also Surgery and Long-term Medication, section 15.1
Capreomycin increased risk of nephrotoxicity and ototoxicity when vancomycin given with capreomycin
Ciclosporin increased risk of nephrotoxicity when vancomycin given with ciclosporin
Cisplatin increased risk of nephrotoxicity and possibly of ototoxicity when vancomycin given with cisplatin
Colestyramine effects of oral vancomycin antagonised by colestyramine Other drugs should be taken at least 1 hour before or 4-6 hours after colestyramine to reduce possible interference with absorption
Colistin increased risk of nephrotoxicity and ototoxicity when vancomycin given with colistin
Diuretics, Loop increased risk of otoxicity when vancomycin given with loop diuretics
Polymyxins increased risk of nephrotoxicity when vancomycin given with polymyxins
Suxamethonium vancomycin enhances effects of suxamethonium
Tacrolimus possible increased risk of nephrotoxicity when vancomycin given with tacrolimus Interactions do not generally apply to tacrolimus used topically; risk of facial flushing and skin irritation with alcohol consumption (see section 13.5.3) does not apply to tacrolimus taken systemically
Vancomycin belongs to Antibacterials and will have the following interactions:

Oestrogens antibacterials that do not induce liver enzymes possibly reduce contraceptive effect of oestrogens (risk probably small, see section 7.3.1) Interactions of combined oral contraceptives may also apply to combined contraceptive patches; in case of hormone replacement therapy low dose unlikely to induce interactions


Adverse Reactions

Cardiovascular

Hypotension.

Dermatologic

Rash; urticaria; pruritus; inflammation at site of injection.

EENT

Hearing loss.

GI

Nausea.

Genitourinary

Increased serum creatinine and BUN; renal failure.

Hematologic

Neutropenia; eosinophilia.

Respiratory

Wheezing; dyspnea.

Miscellaneous

Anaphylaxis; drug fever; chills; Red Man Syndrome (hypotension with or without rash over face, neck, upper chest, and extremities).

Precautions

Pregnancy

Category C .

Lactation

Excreted in breast milk.

Children

Confirming serum levels may be appropriate in newborns. Use of vancomycin with anesthetics may cause erythema and flushing.

Special Risk Patients

Use with caution in patients with preexisting hearing loss, patients receiving ototoxic or nephrotoxic drugs, patients receiving drugs that cause neutropenia; patients with renal function impairment; elderly; newborns.

Hypotension

Too rapid IV infusion or bolus administration may be associated with exaggerated hypotension, including shock and cardiac arrest, with or without maculopapular rash over face, neck, upper chest, and extremities (Red Man or Redneck syndrome). Reaction has been rarely associated with slow infusion or oral or intraperitoneal administration.

Reversible neutropenia

May occur after total dose of 25 g.

Tissue irritation, thrombophlebitis

Give by secure IV route. May minimize thrombophlebitis by giving slowly as dilute infusion.

Overdosage

Symptoms

Increase serum creatinine, increase BUN, hearing loss, ringing in ears, vertigo.

Patient Information

* Explain that IV medication is given at regular intervals to maintain blood levels.
* Tell patient to report hearing loss, ringing in ears, or vertigo to health care provider.
* Explain signs of superinfection (eg, vaginitis).
* Identify symptoms of potential adverse reactions.
* Tell patient to maintain adequate fluid intake.

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Pharm D from B.Z.U Multan,Pakistan

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