Vancomycin | A Brief Overview
Vancomycin, a glycopeptide antibiotic, has been a cornerstone in treating infections caused by a spectrum of bacteria, including notorious methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile. Its mechanism of action involves disrupting bacterial cell wall synthesis, rendering it particularly effective against Gram-positive bacteria. However, achieving therapeutic levels in the bloodstream while minimizing potential side effects requires a delicate balancing act.¹
Challenges in Vancomycin Dosing
Traditionally, vancomycin dosing was guided by monitoring trough levels, the lowest concentration of the drug in the patient's bloodstream between doses. However, this approach left room for uncertainty, potentially leading to suboptimal dosing and, consequently, treatment failure or antibiotic resistance. Moreover, varying patient factors such as age, weight, kidney function, and underlying diseases can complicate dosing calculations.
Vancomycin AUC Dosing Using Bayesian Model-Informed Precision Dosing (MIPD)
What's Included In the Cheat Sheet
About the Drug
Vancomycin is an antibiotic commonly used to treat:
- Infective endocarditis
- Bone infections
- Skin and skin structure infections
Against Staphylococcus & Clostridium difficile Infections:
- Including methicillin-resistant Staphylococcus aureus (MRSA) infections.
- Symptoms of these infections include watery or bloody diarrhea and inflammation of the colon and small intestines.
- The oral formulation of vancomycin is NOT absorbed into the bloodstream, it acts primarily within the intestines.
Adverse Effect of Vancomycin
Vancomycin often can cause unwanted adverse effects depending on the patient, ranging from common effects to more severe effects:
- Stomach pain
- Frequent urination
- Red man’s syndrome
Rare Side Effects of Vancomycin (Oral Route)²
- Hives, skin rash
- redness or other discoloration of the skin
- scaling or welting of the skin
Drug-Drug Interactions (DDA) Of Vancomycin
Depending on the drug interaction, vancomycin excretion levels can increase or decrease, leading to lower or higher vancomycin serum levels.
- Aminoglycosides: The use of vancomycin with aminoglycosides can increase the risk of kidney damage.
- Loop Diuretics: Combined use of vancomycin and loop diuretics can lead to an increased risk of kidney damage due to the potential for dehydration and electrolyte imbalances.
- Nephrotoxic Drugs: Drugs that have the potential to harm the kidneys, like nonsteroidal anti-inflammatory drugs (NSAIDs), can increase the risk of kidney damage when used with vancomycin.
- Anesthetic Agents: Certain anesthetic agents, particularly those used in surgery, can interact with vancomycin and lead to cardiovascular and respiratory side effects.
- Medications that Affect Hearing: Vancomycin, especially when used with other ototoxic drugs, can increase the risk of hearing impairment.
- Anticoagulants (Blood Thinners): There's a theoretical possibility of increased bleeding risk when vancomycin is used concurrently with anticoagulant medications.
- Other Nephrotoxic and Ototoxic Drugs: Drugs known to cause kidney or hearing problems should be used cautiously or avoided when using vancomycin.
List of drugs that can have drug-drug interactions with vancomycin (A-Z)³:
Vancomycin is a branched tricyclic glycosylated nonribosomal peptide often reserved as the "drug of last resort", used only after treatment with other antibiotics has failed to prevent antibiotic resistance. Vancomycin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections:
- Listeria monocytogenes
- Streptococcus pyogenes
- Streptococcus pneumoniae (including penicillin-resistant strains)
- Streptococcus agalactiae
- Actinomyces species
- Lactobacillus species
The combination of vancomycin and an aminoglycoside acts synergistically in vitro against many strains of Staphylococcus aureus, Streptococcus bovis, Enterococci, and the Viridans group streptococci
Vancomycin Renal Toxicity
Vancomycin has been shown to have nephrotoxicity, which can lead to acute kidney injury (AKI). Patients are at a higher risk for developing AKI if they have underlying renal function impairment, use other nephrotoxic medications, are elderly, or are dehydrated. An AKI can be determined by⁴:
- An increase in serum creatinine of >0.5 mg/dL
- A 50% increase from baseline in two consecutive daily readings
- A decrease in calculated CrCl of 50% from baseline on 2 consecutive days in the absence of an alternative explanation.⁵
- Newer studies suggest that a more sensitive threshold of an increase in serum creatinine >0.3 mg/dL under a 48-hour period may be an indicator of AKI.
To lower the occurrence of AKI in patients, using software like PrecisePK can be used to monitor patient serum levels and predict toxicities before they occur. Using a Bayesian AUC calculator can continuously track doses and leverage patient serum levels to ensure the most optimum treatment.
Relevant Reading: Acute Kidney Injury 101 | PrecisePK’s Real-Time Monitoring & Data Driven Analytics for AKI Management