Cross-Reactivity Between Sulfonamides and Loop or Thiazide Diuretics: Is it a Theoretical or Actual Risk?

Hydrochlorothiazide-Induced Exfoliative Rash and Sepsis

Hydrochlorothiazide is a diuretic agent commonly used to treat hypertension, chronic edema from congestive heart failure or cirrhosis, and nephrogenic diabetes insipidus. Diuretics work by increasing urine output and are classified based on the specific renal segments they act on. As with all medications, they are not without their side effects. The most significant and serious include hypovolemia and electrolyte disturbances. Other more rare adverse effects include dermatitis and hypersensitivity reactions. We discuss an 86-year-old male who presented to the emergency room with complaints of lightheadedness and progressive exfoliating rash that began shortly after starting hydrochlorothiazide in an outpatient setting.

Acute urinary obstruction during 99mTc-ethylenedicysteine diuretic renal scintigraphy acquisition: Is furosemide the culprit?

^99mTc-ethylenedicysteine (^99mTc-EC) diuretic renal scintigraphy is an established, safe, and noninvasive study to evaluate relative renal function and drainage. We present a known case of bilateral renal stone disease who presented with acute urinary obstruction detected intraprocedurally on ^99mTc-EC diuretic renography. He was managed subsequently with emergency double J stenting. The development of acute obstruction intraprocedurally in this patient may be resultant of forced diuresis caused by furosemide, dislodging the renal stones in the distal ureters. In the setting of renal calculi, cautious use of furosemide with watchful monitoring may be needed to see for the development of obstruction and manage accordingly.

Sulfonamide Drug Allergy

PURPOSE OF REVIEW

We sought to review past and current literature on sulfonamide drug allergy and distill it in a practical manner to assist the clinician, specifically focusing on cross-reactivity and desensitization.

RECENT FINDINGS

There do not appear to be consistent genetic markers to reliably predict features of or the presence hypersensitivity reactions. Recent evidence continues to alleviate early concerns cross-reactivity between sulfonamide antibiotics and non-antibiotics. Sulfonamide drug allergy is frequently encountered by the practicing clinician. For sulfonamide antibiotics, delayed rash is the most common clinical manifestation. There is no current evidence to support avoidance of all non-antibiotic sulfonamides in those with a reported allergy to sulfonamide antibiotics, although certain scenarios require caution. Available evidence supports the cautious reintroduction of sulfonamide antibiotics via desensitization, which is usually well tolerated and should be considered in those with strong indications for trimethoprim-sulfamethoxazole and a reported sulfonamide allergy.

Cross-reactivity with drugs at the T cell level

PURPOSE OF REVIEW

Cross-reactivity with drugs is an important clinical problem in drug hypersensitivity. Once a patient is labeled 'drug-allergic' all drugs of the same class are withheld and future therapeutic interventions are limited. Here we review cross-reactivity with drugs at the T cell level.

RECENT FINDINGS

Analysis of T cell recognition of various classes of drugs (beta-lactam antibiotics, sulfonamides, local anesthetics) using T cell clones suggests that at the T cell level the whole structure, in particular the core and to a lesser degree side chains, are recognized.

SUMMARY

It is necessary to differentiate cross-reactivity mediated by T cells and antibodies as only the latter seem to recognize side chains exclusively.