Phosphate Dosing - Units and Terminology Confusion

A previous discussion was about selecting a phosphate repletion product.  Selecting a drug product can be confusing because of the similar names of the various formulations - which are not interchangeable.  Harm can come if one is unaware of the other electrolytes (sodium and potassium) that are necessarily included in the phosphate salt drug.  This discussion aims to clarify further confusion that is possible with regards to terminology and also units (and yes, we'll include just a bit of math).  We will also give a clear example where a published trial could lead someone to a wrong conclusion if they do not mind their units.

Phosphorus Repletion: Products and their Electrolytes

Monitoring and balancing electrolytes seems to be an inevitable daily function of physicians and other healthcare professionals in the internal medicine and intensive care settings.  Sodium, potassium, magnesium, calcium, and phosphorus seem to constantly need attention when a patient is ill in the hospital (and also because you're checking them every day, sometimes with and sometimes without good reason).  

Beers Criteria Update 2023 - Seven Changes

The American Geriatrics Society (AGS) 2023 updated AGS Beers Criteria® for potentially inappropriate medication (PIM) use in older adults was released during the AGS annual meeting in May 2023.  This is the sixth update to the criteria which are currently designed to identify potentially inappropriate medications (PIMs) that are best avoided in older adults in general or in specific circumstances.  The criteria were first intended to be applied to the nursing home population but were expanded to apply to all adults 65 years old and older (except for end-of-life settings). 

Inhaled isopropyl alcohol for nausea

An elderly male presents to the emergency department with complaints of nausea, vomiting, and diarrhea starting a day and a half ago.  The diarrhea started abruptly, has occurred almost 10 times, and is non-bloody.  His abdomen is soft but has mild diffuse tenderness.  Vital signs and basic laboratory results are normal except for a potassium of 2.9 mEq/L and an EKG with a QTc interval of 490 msec. 

Pneumococcal vaccine: Which, when, and why?

The pneumococcal vaccine was developed to reduce the disease burden of streptococcus pneumoniae, a gram-postive bacteria that has more than 90 serotypes that can cause diseases in humans.  Some of these infections include pneumonia, meningitis, bacteremia, otitis media, and sinusitis.  There are currently two vaccines on the market to raise immunity against pneumococcal infections - PCV13 (Prevnar 13 - which covers 13 serotypes) and PPSV23 (Pneumovax 23 - which covers 23 serotypes).  The 23-valent vaccine covers all of the serotypes in the

Diabetes discharge checklist

A 55 year old business executive is being discharged from the hospital after a brief admission for cellulitis.  His only PMH is HTN and obesity.  During his stay, his casual serum glucoses were found to be in the high 200s mg/dL and a hemoglobin A1C resulted at 11.6%.  What should be done at the inpatient to outpatient transition to address his diabetes?

Intrapleural tPA and dornase alfa for pleural infection

A 48 year old male is admitted to the hospital after experiencing a fever and malaise for several days.  He states that he has some shortness of breath and chest pain when he coughs.  Imaging of the chest reveals a large loculated effusion and empyema in the right lower lung.  The decision is made to place a chest tube (thoracostomy) and drain the fluid.  The pleural fluid returns with a pH of 7.18, a glucose of 55 mg/dL, and a lactate of 1,150 units/L.  Initial drainage was 200 mL in the first 24 hours, contained pus, and had a putrid odor.  Cultures are pending.  In addition to drainage and appropriate antibiotic therapy, what else can be done to manage this patient?

Metformin in kidney dysfunction - restriction revised

Metformin is the preferred initial pharmacologic therapy in every patient with type 2 diabetes mellitus who does not have a contraindication or intolerance.  It is recommended as monotherapy after diagnosis, continued when adding other medications (including insulin regimens), and should even be considered to prevent diabetes in certain patients (see who at the bottom).  

Old labeling

From approval, the restriction on metformin related to kidney function was as follows

Warfarin dosing nomogram for initiating therapy

A 60 year old female patient presents to the emergency department with complaints of swelling and pain in her right leg.  She recently had her knee replaced and has healed well since the procedure.  She has a PMH of HTN and CKD (Stage IV).  She has no other complaints at this time.  She is diagnosed with a proximal DVT on lower extremity ultrasound and the decision is made to anticoagulate her with warfarin plus a parenteral anticoagulant.  Her baseline INR is 1.28.  What strategy can we use to initiate her on warfarin to reach a therapeutic INR in a reasonable amount of time without overanticoagulating her?

10 things you should know about target-specific oral anticoagulants

Here are some stand-out facts and tips about the target-specific oral anticoagulants.  These agents are becoming increasingly popular in the last few years and there are some nuances among them that you’ll find here. 

To review, target-specific oral anticoagulants (TSOACs) includes dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa).  They’re given orally with either once or twice daily dosing and you don’t need to (and in fact, can’t) monitor any coagulation labs in the typical clinical setting. 

Changes to FDA Pregnancy and Lactation Labeling

On December 3, 2014, the FDA issued a new rule revising the current regulations pertaining to the pregnancy, labor and delivery, and nursing mother sections of the prescribing information for prescription drugs and biologic products. Initiation of this amendment was prompted by the FDA’s goal to provide women and their healthcare providers with sufficient information when deciding which medications to prescribe in pregnant and breastfeeding patients.

^{Why the change?}

Recent data indicate that about 90% of pregnant women take at least one medication and 70% take one or more prescription drugs, potentially putting the fetus at high risk for drug-induced developmental abnormalities. Many pregnant women may also be on medications to control chronic disease states such as hypertension or to manage acute conditions developed during pregnancy such as gestational diabetes.  It is also necessary to consider that about half of all pregnancies are unexpected, leading to unintended drug exposure.

Bridging anticoagulation when treating venous thromboemboli

Given the rising number of options for treating venous thromboemboli (VTE), questions occasionally arise on what is the standard for initiating and continuing anticoagulation.  Questions such as, "How long do we need to overlap parenteral anticoagulation for?" and "Can we begin monotherapy with a new oral anticoagulant?" will be discussed below.

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.

Piperacillin-tazobactam (Zosyn) extended-infusion dosing

Let's start with a patient case.  A 70 year old male patient is admitted to the hospital for a diabetic foot infection.  He has a past medical history of HTN, hyperlipidemia, CKD, gout, and obesity.  He weighs 100 kg and has a Scr of 2.8 mg/dL.  You recall that piperacillin-tazobactam is indicated for diabetic foot infections and are deciding what dosing regimen should be started.  Upon consulting Lexicomp or Micromedex, you will find that piperacillin-tazobactam has a wide dosing range depending on the type of infection being treated in addition to the extent of renal impairment.  Recommended doses range from 2.25 g to 4.5 g intravenously every 6 to 12 hours depending on these factors, leaving much room for uncertainty in many cases.

The following will briefly discuss piperacillin-tazobactam, its pharmacokinetics and pharmacodynamics, and how computer modeling has generated new dosing strategies.  If you just want a simplified way of dosing this medication, feel free to skip down to the 'Take home pearls' at the bottom of the article.

4 Tips for new medical residents

Since July is here and the academic calendar is starting over, it is time for new medical residents to be arriving to the hospital floors.  With this in mind, here are a few tips to help in the transition from student to physician.

Tips for prescribing insulin therapy and diabetes supplies

There are many different insulin preparations and supplies available in order to create individualized regimens for patients.  Here are some tips and a checklist to help avoid getting future calls from pharmacies.