Vancomycin dosing and monitoring in hemodialysis

Let's start with a patient case.  A patient on hemodialysis (M/W/F) is admitted to the hospital with cellulitis who also meets sepsis criteria.  He has a history of an MRSA infection during a previous admission so you want to initiate vancomycin at this time.  The patient is 76 kg and still makes some urine.  What dosing strategy should you choose and when/should vancomycin concentrations be monitored?

Drug interaction between warfarin and acetaminophen?

The management of anticoagulant therapy is an important component of the treatment of various disease states. Maintaining the narrow therapeutic range required for the safe and effective use of warfarin is essential to avoid suboptimal dosing and adverse events. Numerous drug interactions with warfarin are present due to alterations in absorption, distribution, and metabolism.  The severity of interactions with warfarin varies greatly and dictates very different recommendations for management and monitoring. In the most insignificant interactions, no change in dosage or monitoring is necessary, whereas some interactions require a significant empiric reduction in warfarin dosage and close monitoring of INR.

Prevention of postherpetic neuralgia

An elderly patient is admitted to the internal medicine service with a diagnosis of herpes zoster infection in the typical dermatomal distribution.  The patient’s rash is currently not very painful (2/10) but she is concerned about long-lasting pain as her friend had pain from zoster that lasted for months.  What can we use to prevent the development of postherpetic neuralgia?

Postherpetic neuralgia is a common complication of herpes zoster infection and can be challenging to treat.  Drugs approved by the FDA to treat postherpetic neuralgia include pregabalin (Lyrica), gabapentin (Neurontin), and capsaicin patch (high-concentration patch - Qutenza).  Other medications that have been shown in randomized controlled trials to also reduce pain from postherpetic neuralgia include topical lidocaine, tricyclic antidepressants (eg. nortriptyline), opioids, and tramadol¹. 

No medication has been approved for the prevention of postherpetic neuralgia but here is the data on several agents that have been studied:

Is levalbuterol (Xopenex) more effective than albuterol?

The choice between levalbuterol and albuterol continues to be an area of contention for outpatients, in the emergency department, and those admitted into the hospital. Here is a brief explanation of the difference between the two products.

Niacin for dyslipidemia

Niacin is one of our options for managing cholesterol in patients with dyslipidemia.  The benefits of high doses of niacin are well established in reducing triglycerides by 20-50%, reducing LDL by 10-25%, and increasing HDL by 10-30%.  What is not well established, however, are the clinically beneficial endpoints of niacin. 

Use of dexamethasone for vasogenic edema

Vasogenic edema is a result of a disruption of the blood brain barrier that is frequently related to tumors.  The edema can lead to increased intracranial pressure in addition to tissue shifts and brain displacement.  Injury can occur not only from this mechanical shift but also from decreased perfusion that is associated with elevated intracranial pressure.

Dexamethasone is a potent, long-acting glucocorticoid which has no inherent mineralocorticoid activity.  Glucocorticoids have a number of mechanisms for how they reduce inflammation in the body including reduction in lymphocytes, monocytes, basophils, and eosinophils (neutrophils decrease at the site of inflammation but increase in the blood); suppression of the arachadonic acid cascade by inhibiting phospholipase A2 which reduces prostaglandins and leukotrienes; inhibition of other antigen presenting cells; vasoconstriction and decreased capillary permeability; and at large doses, reduced production of antibodies.