Drug Monograph for Serious Infections

Drug Monograph

FOR SERIOUS INFECTIONS ONLY

Drug Monograph: Vancomycin

Drug Name -- Vancocin (brand), Vancomycin HCL -- oral (generic)

This is a time-dependent bactericidal antibiotic, which inhibits cell wall synthesis (Levinson, 2009).

Glycopeptides

VA Class - AM900

CAS Number 1404-93-9

Therapeutic Category -- a tricyclic glycopeptide antibiotic

Pharmacology

Vancomycin is not too well-absorbed from the GI tract after oral administration (Levinson 2009). When given parenterally, it penetrates the bile, pleural, pericardial, synovial and ascitic fluids. It is excreted unchanged by glomerular filtration (Levison).

When taken orally, Vancomycin is not absorbed in the intestines so that it can stop the growth of a severe intestinal condition known as Clostridium difficile-associated diarrhea (Medicine Net, 2012). When vancomycin is given by mouth, it is not absorbed by the body but remains in the intestines. This is to allow it to stop the growth of the Clostridium difficile bacteria. Vancomycin is intended as treatment only for bacterial infections of the intestines. It is not effective for other bacterial infections or infections caused by viruses. Its overuse can decrease its effectiveness (Medicine Net).

Indications

Vancomycin is intended for the treatment of serious or severe bacterial infections caused by susceptible strains of methicillin-resistant staphylococci (PDR, 2012, Drug.com, 2012). It is indicated for use by patients who are allergic to penicillin and cannot or fail to respond to other drugs. It is for infections caused by Vancomycin-susceptible organisms resistant to other anti-microbials. It is indicated as initial therapy when methicillin-resistant staphylococci infection is suspected. It is also effective in the treatment of staphylococcal endocarditis. It has been successfully used in combination with either rifampin or an aminoglycoside or both for early-onset prosthetic valve endocarditis, caused by S. epidermidis or diphtheroid. Its parenteral form may be administered orally in treating antibiotic-associated pseudomembranous colitis caused by C. difficile and for staphylococcal enterocolitis (PDR, Drug.com).

Vancomycin is the drug of choice against serious infection and endocarditis caused by Methicillin-resistant S. aureaus, Methicillin-resistant coagulase-negative Staphylococci, Streptococcus pneumoniae, B-Hemolytic streptococci, Corynebacterium group JK, Viridans streptococci and enterococci (Levinson, 2009). It has been used as an alternative drug for pneumococcal meningitis caused by strains with reduced penicillin sensitivity. But its erratic penetration into the CSF and reported clinical failures make it not advisable for use alone to treat pneumococcal meningitis.

Dosages

For Adults

The usual is 500 mg by IV every 6 hours or 1 g by IV every 12 hours (PDR, 2012). It should be administered no more than at 10 mg per minute or at least 60 minutes, whichever is longer. For those with renal impairment, the initial dose is not less than 15 mg per kg. The daily dosage is about 15 times the GFR in ML per minute. For elderly patients, the dose should be reduced. The initial dose for anephric patients is 15 mg/kg then 1.9 mg/kg/24 hours. The dose for those with marked renal impairment is 250-1,000 mg once every several days and for those with anuria, 1,000 mg every 7-10 days. For PO administration, divided doses of 500-2,000 mg/day should be given for 7-10 days or a maximum dose of 2,000 mg/day. The doses may be diluted in 1 oz of water or administered through an NG tube (PDR).

Vancomycin is taken orally usually 4 times a day for 7-10 days according to the doctor's instructions (Medicine Net, 2012). He determines the dosage according to the medical condition and the patient's response to treatment. Cholestyramine and colestipol can lessen the effects of Vancomycin when they are taken at the same time. If they have to be taken, they should be given at least 3-4 hours from Vancomycin. Vancomycin works best when kept at a constant level at the intestines. Medication should be continued until the prescribed amount is completed even if symptoms have disappeared. Re-infection can occur if the medication is stopped before completion. If the condition persists after 7 days or gets worse, the doctor should be informed (Medicine Net).

For Pediatric Patients

The usual does for all pediatric patients is 10 mg/kg by IV every six hours (PDR, 2012). The initial for newborns is 15 mg/kg, followed by 10 mg/kg every 12 hours for the first week of life. This is continued every 8 hours until their first month of age. Vancomycin should be given for at least 60 minutes. The initial dosage for pediatrics with renal impairment is not less than 15 mg/kg per day or 15 times the GFR in mL/min. Premature infants should have longer dosing intervals. PO administration should be 40 mg/kg/day in 3-4 divided doses for 7-10 days. The maximum is 2,000 mg/day, which may be diluted in 1 oz of water or administered through an NG tube (PDR).

Contraindications

Vancomycin is contraindicated to patients with hypersensitivity to vancomycin (Drug.com, 2012). Commercially prepared frozen Vancomycyn Hydrochloride injections in 5% dextrose may also be contraindicated to those with known allergic reaction to corn or corn products (Drug.com).

Drug-Drug Interactions

The patient should inform the doctor or pharmacist of all prescription and non-prescription or herbal products currently used (Medicine Net, 2012; Levinson, 2012). Aminoglycosides, amphotericin B, other antibiotics, and live bacterial vaccines are special mentions. If treatment requires anesthesia, the doctor or dentist should be told if the patient has been using Vancomycin. Although most antibiotics do not significantly affect hormonal birth control medications, they may decrease the effectiveness of these hormone medications and cause pregnancy (Medicine Net).

Current or sequential systemic or topical use of neurotoxic or nephrotoxic drugs should be carefully monitored (PDR, 2012). Periodic leukocyte count monitoring with drugs, which may cause neutropenia, should be performed. Serial monitoring of renal function and particular care after dosing should also be done to minimize the risk of nephrotoxicity with concomitant aminoglycoside (PDR).

Other Precautions and Potential Adverse Effects

A patient's medical history should be revealed before Vancomycin is administed

(Medicine Net, 2012). Elderly patients should be able to eliminate the drug from their bodies when needed. Otherwise, it should be administered to them with caution for possible sensitivity to its effects. It should be used on pregnant women only when clearly needed. Risks and benefits should be discussed with the doctor. Vancomycin does not pass on to breast milk and is thus not harmful to nursing infants. But the doctor must still be consulted on its effect on breastfeeding (Medicine Net).