Microbiology

The bactericidal action of vancomycin results primarily from inhibition of cell-wall biosynthesis. In addition, vancomycin alters bacterial-cell-membrane permeability and RNA synthesis. There is no cross-resistance between vancomycin and other antibiotics.

NOTE: VANCOCIN HCl Capsules are effective only for the infections noted in the INDICATIONS AND USAGE section. The oral form is not effective for any other type of infection.

Vancomycin has been shown to be active against most strains of the following microorganisms in clinical infections as described in the INDICATIONS AND USAGE section.

Aerobic gram-positive microorganisms

 

Staphylococcus aureus (including methicillin-resistant strains) associated with enterocolitis

Anaerobic gram-positive microorganisms

 

Clostridium difficile antibiotic-associated pseudomembranous colitis.

General

Prescribing VANCOCIN HCl Capsules in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug resistant bacteria.

Clinically significant serum concentrations have been reported in some patients who have taken multiple oral doses of vancomycin for active C. difficile-induced pseudomembranous colitis; therefore, monitoring of serum concentrations may be appropriate in some instances, e.g., in patients with renal insufficiency and/or colitis.

Some patients with inflammatory disorders of the intestinal mucosa may have significant systemic absorption of vancomycin and, therefore, may be at risk for the development of adverse reactions associated with the parenteral administration of vancomycin (see package insert accompanying the intravenous preparation). The risk is greater if renal impairment is present. It should be noted that the total systemic and renal clearances of vancomycin are reduced in the elderly.

Ototoxicity has occurred in patients receiving vancomycin. It may be transient or permanent. It has been reported mostly in patients who have been given excessive intravenous doses, who have an underlying hearing loss, or who are receiving concomitant therapy with another ototoxic agent, such as an aminoglycoside. Serial tests of auditory function may be helpful in order to minimize the risk of ototoxicity.

When patients with underlying renal dysfunction or those receiving concomitant therapy with an aminoglycoside are being treated, serial monitoring of renal function should be performed.

Use of vancomycin may result in the overgrowth of nonsusceptible organisms. If superinfection occurs during therapy, appropriate measures should be taken.

Information for Patients

Patients should be counseled that antibacterial drugs including VANCOCIN HCl Capsules should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When VANCOCIN HCl Capsules are prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by VANCOCIN HCl Capsules or other antibacterial drugs in the future.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No long-term carcinogenesis studies in animals have been conducted.

At concentrations up to 1000 μg/mL, vancomycin had no mutagenic effect in vitro in the mouse lymphoma forward mutation assay or the primary rat hepatocyte unscheduled DNA synthesis assay. The concentrations tested in vitro were above the peak plasma vancomycin concentrations of 20 to 40 μg/mL usually achieved in humans after slow infusion of the maximum recommended dose of 1 g. Vancomycin had no mutagenic effect in vivo in the Chinese hamster sister chromatid exchange assay (400 mg/kg IP) or the mouse micronucleus assay (800 mg/kg IP).

No definitive fertility studies have been conducted.

Pregnancy

Nursing Mothers

Vancomycin is excreted in human milk based on information obtained with the intravenous administration of vancomycin HCl. However, systemic absorption of vancomycin is very low following oral administration of VANCOCIN HCl Capsules (see CLINICAL PHARMACOLOGY). It is not known whether oral vancomycin is excreted in human milk, as no studies of vancomycin concentration in human milk after oral administration have been done. Caution should be exercised when VANCOCIN HCl Capsules are administered to a nursing woman. Because of the potential for adverse events, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Clinical studies of vancomycin HCl for oral use did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Clinically significant serum concentrations have been reported in some patients who have taken multiple oral doses of vancomycin HCl for active C. difficle-induced pseudomembranous colitis; therefore, monitoring of serum concentrations may be appropriate in some instances, e.g., in patients with renal insufficiency and/or colitis. Some patients with inflammatory disorders of the intestinal mucosa may have significant systemic absorption of vancomycin and, therefore, may be at risk for the development of adverse reactions associated with the parenteral administration of vancomycin. The risk is greater if renal impairment is present. It should be noted that the total systemic and renal clearances of vancomycin are reduced in the elderly (see PRECAUTIONS, General).

Nephrotoxicity — Rarely, renal failure, principally manifested by increased serum creatinine or BUN concentrations, especially in patients given large doses of intravenously administered vancomycin HCl has been reported. Rare cases of interstitial nephritis have been reported. Most of these have occurred in patients who were given aminoglycosides concomitantly or who had preexisting kidney dysfunction. When vancomycin HCl was discontinued, azotemia resolved in most patients.

Ototoxicity — A few dozen cases of hearing loss associated with intravenously administered vancomycin HCl have been reported. Most of these patients had kidney dysfunction or a preexisting hearing loss or were receiving concomitant treatment with an ototoxic drug. Vertigo, dizziness, and tinnitus have been reported rarely.

Hematopoietic — Reversible neutropenia, usually starting 1 week or more after onset of intravenous therapy with vancomycin HCl or after a total dose of more than 25 g, has been reported for several dozen patients. Neutropenia appears to be promptly reversible when vancomycin HCl is discontinued. Thrombocytopenia has rarely been reported.

Miscellaneous — Infrequently, patients have been reported to have had anaphylaxis, drug fever, chills, nausea, eosinophilia, rashes (including exfoliative dermatitis), Stevens-Johnson syndrome, toxic epidermal necrolysis, and rare cases of vasculitis in association with the administration of vancomycin HCl.

A condition has been reported that is similar to the IV–induced syndrome with symptoms consistent with anaphylactoid reactions, including hypotension, wheezing, dyspnea, urticaria, pruritus, flushing of the upper body (“Red Man Syndrome”), pain and muscle spasm of the chest and back. These reactions usually resolve within 20 minutes but may persist for several hours.

Treatment — To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison Control Center. Telephone numbers of certified poison control centers are listed in the Physicians' Desk Reference (PDR). In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in your patient.

Adults — VANCOCIN HCl Capsules are used in treating antibiotic-associated pseudomembranous colitis caused by C. difficile and staphylococcal enterocolitis. VANCOCIN HCl Capsules are not effective for other types of infections. The usual adult total daily dosage is 500 mg to 2 g administered orally in 3 or 4 divided doses for 7 to 10 days.

Pediatric Patients — The usual daily dosage is 40 mg/kg in 3 or 4 divided doses for 7 to 10 days. The total daily dosage should not exceed 2 g.