Tyzavan

Vancomycin is a potent glycopeptide antibacterial used to treat serious Gram-positive infections, including MRSA and C. difficile-associated diarrhea. It is available in intravenous and oral formulations for systemic and localized gastrointestinal therapy.

Dosage for Vancomycin is highly individualized and often requires 'therapeutic drug monitoring' (TDM), where blood levels are checked to ensure the dose is safe and effective.

• Systemic Infections (IV): The standard adult dose is typically 15 to 20 mg/kg of body weight administered every 8 to 12 hours. For a patient with normal renal function, this often equates to 2 grams to 3 grams per day in divided doses. In critically ill patients, a 'loading dose' of 25 to 30 mg/kg may be administered to reach therapeutic levels quickly.
• C. difficile-associated diarrhea (Oral): The standard dose is 125 mg taken four times daily for 10 days. For severe or complicated cases, the dose may be increased to 500 mg four times daily.
• Staphylococcal Enterocolitis (Oral): Total daily dosage is 500 mg to 2 grams, administered in 3 or 4 divided doses for 7 to 10 days.

Vancomycin is approved for use in pediatric populations, including neonates, but dosing is strictly weight-based and depends on the age and renal function of the child.

• Neonates (0-28 days): Dosing is complex and based on gestational age and birth weight. It often starts at 10-15 mg/kg every 8 to 24 hours.
• Infants and Children (1 month to 12 years): The usual IV dose is 10 to 15 mg/kg every 6 hours or 20 mg/kg every 8 hours.
• Pediatric Oral Dosing: For C. diff, the typical dose is 40 mg/kg/day in 3 or 4 divided doses, not to exceed the adult dose of 500 mg per day.

Renal Impairment

Because Vancomycin is primarily excreted by the kidneys, dosage adjustments are mandatory for patients with kidney disease. Healthcare providers will calculate the Creatinine Clearance (CrCl) and adjust the frequency of doses. In patients with significant impairment, doses may be given every 48 to 96 hours, or based on blood level 'troughs.'

Hepatic Impairment

Since the liver does not metabolize Vancomycin, standard dose adjustments for liver disease are generally not required. However, if liver disease is accompanied by 'hepatorenal syndrome' (kidney failure caused by liver failure), renal adjustments apply.

Elderly Patients

Older adults often have a natural decline in kidney function. Therefore, lower starting doses and frequent monitoring of renal function and Vancomycin blood levels are recommended for patients over 65.

• Intravenous Administration: Vancomycin must NEVER be given as a rapid 'bolus' or 'push.' It must be diluted (typically to 5 mg/mL) and infused over at least 60 minutes (or 10 mg/minute for doses over 1 gram). Rapid infusion can lead to 'Red Man Syndrome,' a severe flushing reaction.
• Oral Administration: Capsules should be swallowed whole with a full glass of water. They can be taken with or without food. If using the oral solution, use a calibrated measuring device rather than a household spoon.
• Storage: Store capsules and unmixed powder at room temperature (20°C to 25°C). Reconstituted IV solutions are typically stable for 24 hours at room temperature or 14 days when refrigerated, though you should follow the specific manufacturer's instructions.

In a hospital setting, your nurse will manage your schedule. If you are taking oral Vancomycin at home and miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your regular schedule. Do not double the dose to catch up. Consistency is vital to prevent the bacteria from becoming resistant.

Signs of overdose include acute kidney injury (decreased urine output, swelling), hearing loss, or severe skin reactions. In the event of a suspected overdose, emergency medical attention is required. Management is primarily supportive, focusing on maintaining kidney filtration. While hemodialysis does not efficiently remove Vancomycin, high-flux dialysis or hemoperfusion may be used in extreme cases.

> Important: Follow your healthcare provider's dosing instructions exactly. Do not stop the medication early, even if you feel better, as this can lead to a relapse of the infection and antibiotic resistance.

• Infusion-Related Flushing (Red Man Syndrome): This is the most common reaction associated with the IV form. It is characterized by an itchy, red rash affecting the face, neck, and upper torso. It is caused by the rapid release of histamine from mast cells. While it feels like an allergy, it is usually related to the speed of infusion. Slowing the infusion rate typically resolves the issue.
• Nausea and Abdominal Pain: Particularly common with oral Vancomycin as the drug acts directly on the intestinal lining.
• Phlebitis: Inflammation of the vein at the site of injection, which may feel like pain, redness, or a hard cord-like sensation along the vein.

• Chills and Drug Fever

Vancomycin is a 'narrow therapeutic index' drug, meaning the difference between a dose that heals and a dose that harms is very small. Consequently, safety depends heavily on precise dosing and regular clinical monitoring. It should only be used to treat infections that are proven or strongly suspected to be caused by susceptible bacteria to prevent the development of drug-resistant bacteria.

There are currently no FDA black box warnings for Vancomycin. However, its potential for serious toxicity requires it to be used with the same level of caution as drugs that do carry such warnings.

• Infusion Reactions (Red Man Syndrome): Rapid administration can cause a histamine-mediated reaction. This is not a true allergy but can be severe, causing hypotension (low blood pressure) and even cardiac arrest in rare cases. Infusions must be slow.

There are few absolute contraindications for drug combinations with Vancomycin, but certain combinations are avoided unless absolutely necessary due to extreme toxicity risks:

• Live Bacterial Vaccines (e.g., BCG, Typhoid Vaccine): Vancomycin will kill the live bacteria in the vaccine, rendering it ineffective. Vaccination should be delayed until 48 hours after the last dose of Vancomycin.

• Aminoglycosides (e.g., Gentamicin, Amikacin, Tobramycin): These antibiotics are also nephrotoxic and ototoxic. Using them with Vancomycin significantly increases the risk of permanent kidney failure and deafness. If used together, blood levels of both drugs must be monitored daily.
• Loop Diuretics (e.g., Furosemide/Lasix, Ethacrynic Acid): These can increase the risk of ototoxicity (hearing loss) when used concurrently with Vancomycin.

• Hypersensitivity to Vancomycin: The only absolute contraindication is a known, documented severe allergy (anaphylaxis) to Vancomycin or any of its excipients. Because of its unique structure, there is no cross-reactivity with penicillins, making it a safe alternative for penicillin-allergic patients. However, if a patient has had a life-threatening reaction to Vancomycin itself, it must never be used again.
• Intramuscular Administration: Vancomycin is highly acidic and causes tissue necrosis. It must NEVER be given via intramuscular (IM) injection, as it will cause severe pain and death of the muscle tissue at the injection site.

These are conditions where the drug should be used only if the benefit outweighs the risk, under close supervision:

• Pre-existing Renal Impairment: Patients with existing kidney disease are at much higher risk for acute kidney injury. While not an absolute contraindication, it requires significant dose reduction and daily monitoring.

Vancomycin is categorized differently depending on the route of administration.

• Oral Vancomycin: Generally considered safe as it is not absorbed into the bloodstream and cannot reach the fetus.
• Intravenous Vancomycin: Classified as FDA Pregnancy Category C (older system). Animal studies are insufficient, but human data from decades of use suggest that it does not significantly increase the risk of major birth defects. However, because it can cross the placenta and is known to be ototoxic and nephrotoxic, it should be used in pregnant women only when clearly needed. There is a theoretical risk of fetal kidney or hearing damage, though clinical cases are rare. Monitoring of maternal serum levels is essential to protect both the mother and the fetus.

Vancomycin is excreted in human breast milk following IV administration. However, because Vancomycin has extremely poor oral bioavailability, the nursing infant is unlikely to absorb significant amounts of the drug from the milk into their bloodstream. The primary risk to the infant is a potential disruption of their normal gut flora, which could lead to diarrhea or thrush. The American Academy of Pediatrics considers Vancomycin to be usually compatible with breastfeeding, but infants should be monitored for gastrointestinal side effects.

Vancomycin is a glycopeptide bactericidal antibiotic. Its primary molecular target is the D-alanyl-D-alanine portion of the cell wall precursor. By binding to this specific dipeptide, Vancomycin prevents the enzyme transglycosylase from linking the sugar-peptide units into a functional peptidoglycan polymer. It also inhibits transpeptidation (cross-linking). This dual inhibition of the cell wall's structural integrity leads to bacterial cell death. Additionally, Vancomycin may alter bacterial cell membrane permeability and inhibit RNA synthesis, which contributes to its effectiveness against non-dividing bacteria in certain conditions.

The efficacy of Vancomycin is 'time-dependent' and 'concentration-dependent' to varying degrees, but the best predictor of clinical success is the ratio of the Area Under the Curve (AUC) to the Minimum Inhibitory Concentration (MIC). The target ratio is typically AUC/MIC ≥ 400. Unlike some antibiotics that have a 'post-antibiotic effect' (PAE), Vancomycin's PAE is relatively short (about 1-2 hours) for most staphylococci.

| Parameter | Value |