4 T's - Determining the probability of HIT

An earlier post discussed how to bridge argatroban to warfarin in patients with HIT but didn't cover how to determine the likelihood of HIT when it is suspected.  This post will cover the 4 T's that are used to quantify this probability and guide clinical decision-making.

Risk of serotonin toxicity with procarbazine

A question recently came up regarding the risk of serotonin toxicity from a drug interaction between procarbazine and a number of different serotonergic agents.  When checking for an interaction between procarbazine and medications like sertraline, duloxetine, nortriptyline, and tramadol on resources such as Lexicomp and Micromedex, the interactions are listed inconsistently, from no interaction to contraindicated, with varying degrees of evidence, from theoretical to established.

Doxycycline food and OTC interactions

Since it's the time of year again when Lyme disease is a concern for patients in many parts of the United States, I thought it would be good to discuss one issue concerning doxycycline.  Doxycycline is a preferred oral agent for Lyme disease and many of its complications.  It is recommended for a variety of situations when Lyme disease is suspected or confirmed such as1:

• Single dose prophylaxis after tick bite
• Erythema migrans
• Cranial nerve palsy
• Carditis
• Lyme arthritis
• Acrodermatitis chronica atrophicans
• Co-infection with human granulocytic anaplasmosis

When ordering or verifying the typical adult dose of 100 mg orally twice daily, an alert may pop up for an interaction with several drugs including iron, calcium, magnesium, aluminum, or bismuth subsalicylate.  The proposed mechanism for this interaction is chelation in the gastrointestinal tract, compounded by the enterohepatic circulation of doxycycline.  Let's look at some of the data regarding these interactions.

Update on niacin - Results from the HPS2-THRIVE study

In a previous blog post, niacin for dyslipidemia, we discussed the concerns regarding niacin's lack of improvement of clinically meaningful endpoints in addition to some of its adverse effects and how to deal with them.  Recently, final results of the HPS2-THRIVE study have been published.  Here are a few highlights of the results of this study.

More cardiovascular safety data for azithromycin

There has been concern in recent years regarding cardiovascular risk in patients using azithromycin which I discussed in an earlier post found here.

A recent study in JAMA further examined cardiovascular risk and mortality in a retrospective review of more than 60,000 patients in the VA Health System.  This study specifically identified patients with a diagnosis of pneumonia who were treated with antibiotics including azithromycin compared to other guideline-concordant antibiotics.  Their outcomes of measure were 30-day mortality, 90-day mortality, any cardiovascular event, myocardial infarction, heart failure, or cardiac arrhythmias.  The mean patient age was 78 years old and comorbid conditions were fairly common (35% with diabetes, 52% with COPD, 26% with heart failure).

Converting systemic corticosteroids

Let’s start with a patient case.  A patient is being treated with methylprednisolone 20 mg IV q6 hours for some inflammatory process and is clinically improving.  She can now tolerate oral medication and we would like to simplify her dosing regimen to transition to outpatient care. How can we manage her methylprednisolone dosing?

One issue that comes up frequently on the internal medicine service is the potency of different corticosteroids relative to each other and the correct way to convert the doses. Below is the chart that shows the equivalent dose of the various agents we commonly use.