Listen in as I pick Victoria Arsenault’s, PharmD, brain about two totally unrelated topics: vancomycin and oral diabetic agents.
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What is Vancomycin?
- Glycopeptide antibiotic with great gram positive coverage
- Drug of choice for MRSA infections
- Indicated as a first line agent for empiric therapy in infectious work up
Side Effects of Vancomycin
Nephrotoxicity
Associated with trough levels >20 or doses > 4g/day, prolonged therapy, concomitant agents such as IV contrast, Piperacillin/Tazobactam (Zosyn), loop diuretics, and aminoglycosides.
Ototoxicity
Associated with high peaks, can be transient or permanent, concomitant aminoglycoside use. Very rare.
Vancomycin Induced Infusion Reaction
- Formerly called Red man syndrome
- Histamine related infusion reaction
- Erythema and itching usually trunk, neck, and chest
- Mitigated by increasing infusion time (500 mg/hr) and/or antihistamine administration
- NOT ANAPHYLAXIS
Upcoming Changes to Vancomycin Administration
Studies have shown that adjusting vancomycin dosing by using the area under the curve (or AUC) can best predict efficacy and safety for vancomycin. This basically assesses vancomycin exposure to the patient.
For AUC dosing we use two data points, peak and trough, to calculate more accurate pharmacokinetics. This method allows for troughs as low as 10 in severe infections!
The AUC method of dosing presents some work flow changes for both pharmacists and nurses. Nurses will need to be meticulous about collecting the peak and trough lab draws.
- Troughs will always be 30 minutes to an hour prior to a dose
- Peaks should be drawn an hour after an infusion dose is completed
THE BIG TAKEAWAY: AUC vancomycin dosing is a more accurate way to maximize the antibiotic’s efficacy while minimizing the risk of nephrotoxicity
Why do we often opt for insulin instead of oral diabetes meds in the hospital?
- It is much easier to control hyperglycemia with insulin vs PO DM medications, also allows fast titrations
- Being acutely ill can change glucose metabolism, making PO meds less predictable
- Also easier for patients who may not be eating as some medications can cause hypoglycemia
When could you advocate for your patient to resume home oral diabetic agents?
- If they have not received IV contrast in the last 48 hours
- If their blood glucose levels are well controlled
- If they are not NPO, although this may not be a factor depending on the medication (see table below)
Oral Diabetic Agents
| Biguanides: Metformin | MOA: insulin sensitizer, inhibits gluconeogenesis, increases endogenous insulin post prandial Pros: Cheap, no hypoglycemia risk, weight neutral, strong A1C reduction: 1-2% Cons: Diarrhea/GI upset (taking with food can decreased GI upset), pill burden |
| SGLT2 Inhibitors: Empagliflozin (Jardiance), Dapagliflozin (Farxiga), Canagliflozin (Invokana), Ertugliflozin (Steglatro) | MOA: blocks reabsorption of glucose makes you pee out your sugar Pros: no hypoglycemia risk, weight loss, CV/CHF/CKD benefit, decreases BP, moderate A1C reduction: 0.5-1% Cons: UTI risk (females>males), increased UO, dehydration, hypotension, DKA |
| DPP-4 Inhibitors: Sitagliptin (Januvia), Linagliptin (Tradjenta), Saxagliptin (Onglyza), Alogliptin (Nesina) | MOA: incretin mimetic (increases insulin production) Pros: no hypoglycemia risk, weight neutral, well-tolerated, QD dosing, moderate A1C reduction (0.5 – 1%) Cons: Abdominal discomfort |
| GLP-1 agonists: Trulicity, Rybelsus | MOA: slows gastric motility, increases endogenous insulin production Pros: Weight loss, no hypoglycemia risk, strong A1C reduction: 1-2% Cons: Injections (except Rybelsus), needs refrigeration, not studied extensively in HD patients, nausea, GI upset, diarrhea, constipation |
| Sulfonylureas: Glipizide (Glucotrol), Glyburide (Diabeta), Glimepiride (Amaryl) | MOA: insulin secretagogue Benefits: Cheap, strong A1C reduction (1-2%) Cons: Hypoglycemia – do not take if not eating, weight gain |
| Meglitinides: Nateglinide (Starlix), Repaglinide (Prandin) | MOA: Stimulates insulin secretion Pro: Strong A1C reduction (1-2%) Cons: Hypoglycemia – do not take if not eating |