What are some clues to help distinguish viral from drug-induced exanthems?

It is often difficult to distinguish but here are some clues ...
  • viral exanthems often have associated fever, malaise, sore throat and conjunctivitis; although drug reactions may have these features also
  • viral exanthems happen more frequently in children; although adults can get them too 
  • a rash that develops within 3 days of a drug being initiated for an infection is more likely secondary to the infection because of the time required for hypersensitivity to develop in a patient not previously sensitized to a particular drug

Selected infections and Other Conditions that Often Include an Exanthem and Characteristics that Help Differentiate Them from an Exanthematous Drug Eruption.  (click image to enlarge)


 Stern, R.  "Exanthematous Drug Eruptions"  NEJM.  28 June 2012.

If SUX sucks, and ROC rocks, then Sugammadex _________.

If anyone remembers studying for their SAT’s back in the day, complete this sequence:

If SUX sucks, and ROC rocks, then Sugammedex _________.

In a word, “unavailable.” 

Sugammadex is a selective muscle relaxant-binding agent. As a result of its chemical structure, modified cyclodextrin compound with a hydrophilic outer surface and a lipophilic central cavity, sugammadex encapsulates both rocuronium and vecuronium.  This encapsulation creates a concentration gradient by which rocuronium or vecuronium leaves the neuromuscular junction for the plasma and then subsequently bound by sugammadex (think DigiFab).  The result is a dramatically shortened duration of effect of rocuronium or vecuronium.  At a typical surgical reversal dose of 4 mg/kg the median time to reach train of four ratio of 0.9 is 2.4 minutes after rocuronium or 3.4 minutes for vecuronium compared to 49 minutes using neostigmine.  Although it is less clear how fast the reversal will be in the setting of RSI in the ED, using a sugammadex dose of 16 mg/kg, the duration of roc or vec is likely around 5 minutes.

Moreover, the drug is safe. Minimal (if any) of the typical new drug curses. There is no evidence of QT prolongation, hepatotoxicity, renal toxicity, bleeding, etc.  Concerns surrounding impaired fracture healing and bone deposition seem to have been cleared up. No evidence of drug interactions, though it may reduce flucloxacillin (not available in the US) and the effectiveness of oral contraceptives. Hypersensitivity reactions have been reported in clinical trials (actually 1 healthy volunteer). 

Sugammadex is relatively expensive, especially for use in the ED, probably running about $1000 per dose.  This brings the argument, should sugammadex be used after every administration of roc? Or reserved for can’t intubate, can’t ventilate situations?  The bigger argument, especially for those of us in the US; where is this drug? In 2008, the new drug approval rejected by the FDA but approved by EMA? (It was rejected for concerns of the hypersensitivity reaction).

Really FDA? This is a game-changing drug. While there are important debates to be had surrounding the drug, they seem to pale in comparison to current problems with already (recently) approved drugs: dabigatran, rivaroxaban, ticagrelor, IV acetaminophen…

I can only hope that in the near future we’ll all be talking about this drug within the context of who, how and when to use it, and give the FDA a pat on their back for actually taking their time with an drug to make sure it’s safe and effective.